Elegant Code » NHibernate http://elegantcode.com Tue, 15 May 2012 10:00:00 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 FubuMVC From Scratch – Part 4 Persistence http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments Wed, 25 Mar 2009 21:22:00 +0000 Ryan Kelley http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/ Previous posts in series:

Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project

We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.

Class and Interfaces we have to implement:

  • ISessionSourceConfiguration
  • SQLServerSessionSourceConfiguration
  • IUnitOfWork
  • INHibernateUnitOfWork
  • NHibernateUnitOfWork
  • IRepository
  • NHibernateRepository
  • DomainEntity
  • IDomainQuery
  • FubuSamplePersistenceModel

Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence

Before we start you probably want to go ahead and add the following references to your core project and Web project

FubuMVC-Persist-Ref

Let’s just work our way down the list and get these files implemented.

ISessionSourceConfiguration

public interface ISessionSourceConfiguration
{
    bool IsNewDatabase { get; }
    ISessionSource CreateSessionSource(PersistenceModel model);
}

SQLServerSessionSourceConfiguration

public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration
{
    #region Implementation of ISessionSourceConfiguration
 
    public bool IsNewDatabase
    {
        get { return false; }
    }
 
    public ISessionSource CreateSessionSource(PersistenceModel model)
    {
        var properties = GetProperties();
        var source = new SessionSource(properties, model);
 
        create_schema_if_it_does_not_already_exist(source);
 
        return source;
    }
 
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)
    {
        if (IsNewDatabase) source.BuildSchema();
    }
 
    protected IDictionary<string, string> GetProperties()
    {
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);
        config.ShowSql();
        config.UseOuterJoin();
 
        return config.ToProperties();
    }
    #endregion
}

A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.

IUnitOfWork

public interface IUnitOfWork : IDisposable
{
    void Initialize();
    void Commit();
    void Rollback();
}

INHibernateUnitOfWork

public interface INHibernateUnitOfWork : IUnitOfWork
{
    ISession CurrentSession { get; }
}

NHibernateUnitOfWork

public class NHibernateUnitOfWork : INHibernateUnitOfWork
{
    private ITransaction _transaction;
    private bool _isDisposed;
    private readonly ISessionSource _source;
    private bool _isInitialized;
 
    public NHibernateUnitOfWork(ISessionSource source)
    {
        _source = source;
    }
 
    public void Initialize()
    {
        should_not_currently_be_disposed();
 
        CurrentSession = _source.CreateSession();
        begin_new_transaction();
 
        _isInitialized = true;
    }
 
    public ISession CurrentSession { get; private set; }
 
    public void Commit()
    {
        should_not_currently_be_disposed();
        should_be_initialized_first();
 
        _transaction.Commit();
 
        begin_new_transaction();
    }
 
    private void begin_new_transaction()
    {
        if (_transaction != null)
        {
            _transaction.Dispose();
        }
 
        _transaction = CurrentSession.BeginTransaction();
    }
 
    public void Rollback()
    {
        should_not_currently_be_disposed();
        should_be_initialized_first();
 
        _transaction.Rollback();
 
        begin_new_transaction();
    }
 
    private void should_not_currently_be_disposed()
    {
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);
    }
 
    private void should_be_initialized_first()
    {
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");
    }
 
    public void Dispose()
    {
        if (_isDisposed || !_isInitialized) return;
 
        _transaction.Dispose();
        CurrentSession.Dispose();
 
        _isDisposed = true;
    }
}

IRepository

public interface IRepository
{
    void Save<ENTITY>(ENTITY entity)
        where ENTITY : DomainEntity;
 
    ENTITY Load<ENTITY>(Guid id)
        where ENTITY : DomainEntity;
 
    IQueryable<ENTITY> Query<ENTITY>()
        where ENTITY : DomainEntity;
 
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)
        where ENTITY : DomainEntity;
 
    void Delete<ENTITY>(ENTITY entity);
 
    void DeleteAll<ENTITY>();
}

NHibernateRepository

public class NHibernateRepository : IRepository
{
    private readonly INHibernateUnitOfWork _unitOfWork;
 
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)
    {
        _unitOfWork = unitOfWork;
    }
 
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity
    {
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);
    }
 
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity
    {
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);
    }
 
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity
    {
        return _unitOfWork.CurrentSession.Linq<ENTITY>();
    }
 
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity
    {
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);
    }
 
    public void Delete<ENTITY>(ENTITY entity)
    {
        _unitOfWork.CurrentSession.Delete(entity);   
    }
 
    public void DeleteAll<ENTITY>()
    {
        var query = String.Format("from {0}", typeof(ENTITY).Name);
        _unitOfWork.CurrentSession.Delete(query);   
    }
}

DomainEntity

Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository

public class DomainEntity : IEquatable<DomainEntity>
{
    public virtual Guid ID { get; set; }
 
    public virtual bool Equals(DomainEntity other)
    {
        if (ReferenceEquals(null, other)) return false;
        if (ReferenceEquals(this, other)) return true;
        return other.ID.Equals(ID);
    }
 
    public override bool Equals(object obj)
    {
        if (ReferenceEquals(null, obj)) return false;
        if (ReferenceEquals(this, obj)) return true;
        if (obj.GetType() != GetType()) return false;
        return Equals((DomainEntity)obj);
    }
 
    public override int GetHashCode()
    {
        return ID.GetHashCode();
    }
 
    public static bool operator ==(DomainEntity left, DomainEntity right)
    {
        return Equals(left, right);
    }
 
    public static bool operator !=(DomainEntity left, DomainEntity right)
    {
        return !Equals(left, right);
    }
}

IDomainQuery

public interface IDomainQuery<ENTITY>
    where ENTITY : DomainEntity
{
    Expression<Func<ENTITY, bool>> Expression { get; }
}

FubuSamplePersistenceModel

namespace FubuSample.Core.Domain.Persistence
{
    public class FubuSamplePersistenceModel : PersistenceModel
    {
        public FubuSamplePersistenceModel()
        {
            addMappingsFromThisAssembly();
        }
    }
}

Now that we have all the puzzle pieces in place we need to hook them up and make them do some work. Open up FubuSampleWebRegistry

And add the following code:

protected override void configure()
{
    ForRequestedType<ISessionSourceConfiguration>().AsSingletons()
        .TheDefault.Is.OfConcreteType<SQLServerSessionSourceConfiguration>();
 
 
    ForRequestedType<ISessionSource>().AsSingletons()
        .TheDefault.Is.ConstructedBy(ctx =>
                                     ctx.GetInstance<ISessionSourceConfiguration>()
                                         .CreateSessionSource(new FubuSamplePersistenceModel()));
 
    ForRequestedType<IUnitOfWork>().TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<INHibernateUnitOfWork>());
 
    ForRequestedType<INHibernateUnitOfWork>().CacheBy(InstanceScope.Hybrid)
        .TheDefault.Is.OfConcreteType<NHibernateUnitOfWork>();
 
    ForRequestedType<IRepository>().TheDefault.Is.OfConcreteType<NHibernateRepository>();
}

With a little luck and all of our mad skills, we should be able to talk to the database now. So we need to plumb our simple product object up to talk to NHibernate. We will do this with a mapping file, and since we are using FluentNHibernate we can do this strongly typed.

Make the following modifications to Product: Extend DomainEntity and get rid of Id Property, it is inherited

public class Product : DomainEntity
{
    public virtual string Name { get; set; }
    public virtual string Description { get; set; }
}

Add mapping file for Product:

namespace FubuSample.Core.Domain.Mapping
{
    public class ProductMap : ClassMap<Product>
    {
        public ProductMap()
        {
            Id(e => e.ID).GeneratedBy.GuidComb();
 
            Map(p => p.Name);
            Map(p => p.Description);
            
        }
    }
}

You may also want to setup your connection string at this point in the Web.Config file, mine looks like this:

<add name="MYDBKEY" connectionString="Data Source=LOCALHOST;initial catalog=FubuSample;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />

I also created an empty database in my local SQL Server instance called “FubuSample” And then I went back to SQLServerSessionSourceConfiguration and changed the value of IsNewDatabase to return true. This will create the schema for the database when the application first runs. There is a multitude of different ways that we can handle this, but this was easy for the tutorial purposes.

Next we will add a behavior to our core project and tell FubuMVC to apply that behavior to all or our ControllerActions.

Create a class named “access_the_database_through_a_unit_of_work” in your Core.Web.Behaviors namespace. The contents will look like this:

public class access_the_database_through_a_unit_of_work : IControllerActionBehavior
{
    private readonly IUnitOfWork _unitOfWork;
 
    public access_the_database_through_a_unit_of_work(IUnitOfWork unitOfWork)
    {
        _unitOfWork = unitOfWork;
    }
 
    public IControllerActionBehavior InsideBehavior { get; set; }
    public IInvocationResult Result { get; set; }
 
    public OUTPUT Invoke<INPUT, OUTPUT>(INPUT input, Func<INPUT, OUTPUT> func)
        where INPUT : class
        where OUTPUT : class
    {
        _unitOfWork.Initialize();
 
        try
        {
            var output = InsideBehavior.Invoke(input, func);
            Result = InsideBehavior.Result;
 
            _unitOfWork.Commit();
 
            return output;
        }
        catch
        {
            _unitOfWork.Rollback();
            throw;
        }
        finally
        {
            _unitOfWork.Dispose();
        }
    }
}

Now to tell FubuMVC what to do, open up Global.asax.cs or your Bootstrapper, wherever you are doing the configuration of FubuMVC. In this project we are doing it in Global.asax.cs Add a new behavior to the section that starts with “x.ByDefault.EveryControllerAction” so it looks like this:

x.ByDefault.EveryControllerAction(d =>
   {
       d.Will<execute_the_result>();
       d.Will<access_the_database_through_a_unit_of_work>();
   });

The last thing we will do is open up HomeController and add this code above the Index action:

private IRepository _repository;
 
public HomeController(IRepository repository)
{
    _repository = repository;
}

I also modified the Index action to go ahead and create some database values before we query for them just so we can test this thing. (I only did this for the tutorial, I swear) So modify the Index action to look like this:

public IndexViewModel Index(IndexSetupViewModel inModel)
{
    var prod1 = new Product {Name = "TestProduct1", Description = "This is a test product"};
 
    _repository.Save(prod1);
 
    var prod2 = new Product {Name = "TestProduct2", Description = "This is a test product"};
 
    _repository.Save(prod2);
 
    var outModel = new IndexViewModel();
 
    var productList = _repository.Query<Product>();
 
    outModel.Products = productList.ToList().Select(x => new ProductDisplay(x));
 
    return outModel;
}

Now with you should be able to run your web app and browse to /home and all this will be executed and you will be on your way to creating a whole bunch of persist able objects for use with your FubuMVC app.

As always, feedback is welcome.

]]> http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/feed/ 9 Book review: NHibernate in Action http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/?utm_source=rss&utm_medium=rss&utm_campaign=book-review-nhibernate-in-action http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/#comments Sat, 14 Jun 2008 20:42:15 +0000 Jan Van Ryswyck http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/ kuate_cover150 Writing this book review feels kind of weird  because it hasn't actually hit the shelves yet. It is accessible however through the Manning Early Access Program. This book provides a clear insight of using NHibernate as the data access layer of your applications and beyond.

The excessive amount of NHibernate features  isn't the only thing that is written down. There is also a good coverage of OO principles and Domain-Driven Design, although it isn't the primary objective of the book of course. This is especially true for the first and the last three chapters. If you've already read the nominal books DDD and you are familiar with Persistence Ignorance, then you can safely skim through these chapters unless you want to see the interpretation of the authors when it comes to these principles. If you are new to these concepts, then these chapters are of great value to wet your appetite.

Although this book covers a lot of ground, I would certainly recommend it when you're rather new to NHibernate and ORM's in general. I guess this still includes me, although I've been using NHibernate for quite some time now. If you already have some experience with NHibernate, then this book probably doesn't teach you that much. Still, it can quickly get you up to speed when you want to use a particular feature that you haven't used before.

The only minor thing about this book is that I'm afraid that it will soon be out-of-date. The book only covers NHibernate 1.2.x and no features from the upcoming 2.0 release, which adds a lot of new and interesting features. It would be nice if the book already covered some of these features as most of them are ported from Hibernate itself, which is the original Java version.

On the other hand, this book provides an in-depth view of the basic features of NHibernate, which aren't necessarily going to change that much over time anyway.

Let me round off this post by saying that I'm really impressed by the list of books that Manning is going to release the next couple of months. These are the ones that I'm particularly interested in:

I already bought LINQ in Action and also read a lot of good things about C# in Depth, which I'm going to pick up soon.

Take care.

]]> http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/feed/ 7 Integrating Castle Windsor and NHibernate with WCF http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/?utm_source=rss&utm_medium=rss&utm_campaign=integrating-castle-windsor-and-nhibernate-with-wcf http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/#comments Sun, 18 May 2008 14:08:20 +0000 Jan Van Ryswyck http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/ Up until now, we were using the NHibernate facility of Castle Windsor for managing our NHibernate sessions in WCF. But, we want to have a session-per-request approach as one would use when integrating NHibernate with a regular web application.

Yesterday I did a small spike to figure out how this should work. It turned out to be pretty easy. I used this excellent blog post written by Oran Dennison as my guide.

First I created a class that implemented the IServiceBehavior interface.

public class DIServiceBehavior : IServiceBehavior
{
    private readonly ISessionFactory _sessionFactory;

    public DIServiceBehavior()
    {
        _sessionFactory = new Configuration()
            .Configure()
            .BuildSessionFactory();

        XmlConfigurator.Configure();    // Log4Net
    }

    public void ApplyDispatchBehavior(
             ServiceDescription serviceDescription, 
             ServiceHostBase serviceHostBase)
    {
        foreach(ChannelDispatcherBase cdb in 
                serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if(cd != null)
            {
                foreach(EndpointDispatcher ed in cd.Endpoints)
                {
                    ed.DispatchRuntime.InstanceProvider =
                        new DIInstanceProvider
                            (serviceDescription.ServiceType,
                              _sessionFactory);
                }
            }
        }
    }

    public void AddBindingParameters(
                ServiceDescription serviceDescription, 
                ServiceHostBase serviceHostBase,
                Collection<ServiceEndpoint> endpoints, 
                BindingParameterCollection bindingParameters) 
    { }
    
    public void Validate(ServiceDescription serviceDescription, 
                         ServiceHostBase serviceHostBase) 
    { }
}

The SessionFactory is created in the constructor because the ApplyDispatchBehaviour method can be called multiple times (for each endpoint).

The next step is to create an instance provider by creating a class that implements the IInstanceProvider:

public class DIInstanceProvider : IInstanceProvider
{
    private const String NHibernateSessionKey = 
        "NHibernate.Session";

    private readonly Type _serviceType;
    private IDependencyContainer _dependencyContainer;
    private readonly ISessionFactory _sessionFactory;
    private ISession _session;

    public DIInstanceProvider(Type serviceType,
                               ISessionFactory sessionFactory)
    {
        Debug.Assert(null != serviceType, 
                     "null != serviceType");
        _serviceType = serviceType;

        Debug.Assert(null != sessionFactory, 
                     "null = sessionFactory");
        _sessionFactory = sessionFactory;
    }

    public Object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public Object GetInstance(InstanceContext instanceContext, 
                                Message message)
    {
        _dependencyContainer = new DependencyContainer();

        _session = _sessionFactory.OpenSession();
        _dependencyContainer
          .AddComponentInstance(NHibernateSessionKey, _session);

        return _dependencyContainer.Resolve(_serviceType);
    }

    public void ReleaseInstance(InstanceContext instanceContext, 
                                 Object instance)
    {
        if(null != _session)
        {
            _session.Close();
            _session = null;
        }

        if(null != _dependencyContainer)
        {
            _dependencyContainer.Dispose();
            _dependencyContainer = null;
        }
    }
}

I created a wrapper class around for Castle Windsor named DependencyContainer.  The GetInstance method opens a new session using the SessionFactory object we instantiated in the service behavior class. The session object is then registered with Castle Windsor. We can now implement our repositories like this:

public class SomeAggregateRepository
{
    private ISession _session;

    public SomeAggregateRepository(ISession session)
    {
        _session = session;
    }
    
    public SomeAggregate Get(Int64 id) 
    {
        return _session.Get<SomeAggregate>(id);
    }
}

When our service operation has been executed, the NHibernate is released by the ReleaseInstance method. Finishing our example, we need to implement a custom ServiceHost and a ServiceHostFactory:

public class DIServiceHost : ServiceHost
{
    public DependencyInjectionServiceHost() 
        : base() 
    { }
    
    public DIServiceHost(Type serviceType, 
                         params Uri[] baseAddresses) 
        : base(serviceType, baseAddresses) 
    { }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new DIServiceBehavior());
        base.OnOpening();
    }
}

public class DIServiceHostFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(
            Type serviceType, Uri[] baseAddresses)
    {
        return new DIServiceHost(serviceType, baseAddresses);
    }
}

The custom ServiceHostFactory class can now be used in the ServiceHost file required when doing IIS hosting:

<%@ ServiceHost Language="C#" 
                Debug="true" 
                Service="WindsorService.MyWindsorService" 
                Factory="WindsorService.DIServiceHostFactory"
                CodeBehind="MyWindsorService.svc.cs" %>

There is also another way for achieving this that I will be investigating the next week or so using the WCF Integration Facility for Castle Windsor. For some reason it is not available in the current release of the Castle stack so I have to grab it from the trunk.

If you have any thoughts, improvements or suggestions I'm glad to hear them from you, my dear reader. It's the only way I'll ever learn :-).

Till next time.

]]> http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/feed/ 9 Implementing NHibernate Interceptors http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/?utm_source=rss&utm_medium=rss&utm_campaign=implementing-nhibernate-interceptors http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/#comments Thu, 15 May 2008 18:29:26 +0000 Jan Van Ryswyck http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/ One of the areas where NHibernate really shines is it's high extensibility features. The NHibernate API provides a massive amount of interfaces that can be implemented for your own custom extension pleasure.

For me this is a nice change as opposed to the many sealed API's put out by the Redmond collective (WCF being the exception, the Entity Framework confirming the rule).

Anyhow, with great power comes great responsibility. Today I encountered a rather difficult problem with NHibernate that could have been easily prevented by reading the documentation (note to self: use the CTRL-Q shortcut of Resharper more often).

We have implemented an interceptor for automatically configuring audit information as described by this great post from Ray Houston. 

public class AuditInformationInterceptor 
    : EmptyInterceptor
{
    Boolean OnSave(Object entity, Object id, Object[] state, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }

    Boolean OnFlushDirty(Object entity, Object id, 
        Object[] currentState, Object[] previousState, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }                  
}

The mistake we made is that we manipulated the audit information of the entity directly in the OnSave and OnFlushDirty methods. This only became apparent when saving an aggregate root with his child entities. Everything worked fine until we wanted to persist one of the child entities that should have been a piece of cake but turned out to be the messenger of trouble. NHibernate refused to perform an INSERT statement, but instead threw an UPDATE statement at us.

After some debugging we found out that the audit information should have been manipulated through the state and currentState arguments of the OnSave and OnFlushDirty methods respectively.

The documentation of the OnSave method clearly states:

The interceptor may modify the state, which will be used for the SQL INSERT
and propagated to the persistent object

Lesson relearned.

I'm off, reading some docs. Until next time.

]]> http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/feed/ 3 On Persistence http://elegantcode.com/2008/05/01/on-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=on-persistence http://elegantcode.com/2008/05/01/on-persistence/#comments Thu, 01 May 2008 19:18:43 +0000 Jan Van Ryswyck http://elegantcode.com/2008/05/01/on-persistence/ Earlier this week, I managed to convince our very wise decision makers to start using NHibernate for our persistence layer. My team mate on the project describes how it went. While I was reading Jeremy's train of thoughts, the following four lines made me realize we did the right thing:

Why are teams still writing persistence code by hand?  There's a bazillion persistence tools out there that all save development costs in some way over writing data access code by hand.  With very few exceptions, I'd say that at this point that if you're writing ADO.Net code or SQL by hand, you're stealing money from your employer. 

As another co-worker and NHibernate fan thoughtfully mentioned while congratulating us:

A small step for man, but a giant leap for mankind.

Few. What a week this turns out to be.

]]> http://elegantcode.com/2008/05/01/on-persistence/feed/ 2 NHibernate 2.0 and Cascading Deletes http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-20-and-cascading-deletes-2 http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/#comments Sat, 12 Apr 2008 18:58:12 +0000 Jan Van Ryswyck http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/ The first alpha version of NHibernate 2.0 has been released some time ago. Oren has put a nice overview of the new features and the bugs that are solved for this first drop. In spite the fact that they put the word 'alpha' in the version name, it is actually RTM quality!

One of the great new additions is the on-delete attribute of the key element for mapping collections:

<set name="Permissions" inverse="true" cascade="save-update">
  <key name="Authorization" on-delete="cascade"/>
  <one-to-many class="Permission"/>
</set>

This particular feature solves the issue I've had with one-shot deletes on inverse collections (which I described here). Configuring it this way ensures that NHibernate relies on database-level ON CASCADE DELETE foreign key constraints. This implies that when an object with a collection of child objects is deleted, a single DELETE  statement is used to remove all children at once instead of individual DELETE statements for each child object (which are called orphans at this point).

There are some things that you have to take into account here. First, this option bypasses NHibernate's optimistic locking strategy for versioned data. Second, make sure that you configure cascade="save-update" instead of cascade="all" to prevent NHibernate from performing delete cascade checks. This is important when lazy loading is enabled for the collection because it prevents that NHibernate loads one-to-many associations into memory.

I'm really excited about this new release. Kudos to the men and women who have put so much effort in building such a wonderful ORM solution!

Till next time

]]> http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/feed/ 0 A New NHibernate Blog http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/?utm_source=rss&utm_medium=rss&utm_campaign=a-new-nhibernate-blog http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/#comments Tue, 01 Apr 2008 15:26:32 +0000 Alex Mueller http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/ Craig Neuwirt recently started a blog focused on NHibernate, as mentioned by Ayende. NHibernate is an ORM tool I have used on current and past projects and it is something I feel I would like I want to study further. So far, Craig is walking us through NHibernate from the ground-up, with the latest and greatest. I anticipate this being an informative blog to follow. The NHibernate FAQ Craig Neuwirt Hibernating Rhinos]]> http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/feed/ 2 NHibernate IQuery to ISQLQuery Black Magic http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-iquery-to-isqlquery-black-magic http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/#comments Fri, 16 Nov 2007 06:12:55 +0000 Jason Grundy http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/ posted on the forums and learned that: I'd run into a known bug / limitation. Therefore I resorted to using ISQLQuery (yuk). I fixed several repository methods and then I ran into a very complicated IQuery. It was very painful to write the first time. In fact it was this experience that had caused me to change to using ICriteria as my default query method with specifications. I had a full suite of unit tests to protect me so I was confident that I could make the changes without breaking anything but I didn't want to do the conversion manually. Surely there was a trick? It turns out that there is - NHibernate.Hql.Classic.QueryTranslator. The property that I needed is protected but thanks to a quick search of the forums I didn't even need to write my own reflection based method of calling it because someone had done it for me (thanks Nels). So what I did was take the HQL and convert it to SQL. I then did some string replacement to morph the SQL into what I needed. I am not proud of this but it was fast and it goes to show for flexible NHibernate is if you want to do some certifiable things.]]> http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/feed/ 0 DTOs / Presentation Model and ICriteria http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/?utm_source=rss&utm_medium=rss&utm_campaign=dtos-presentation-model-and-icriteria http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/#comments Tue, 06 Nov 2007 06:11:41 +0000 Jason Grundy http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/ NHibernate Projections I used HQL (IQuery) in the repository to define the query. There are a some things that I don't like about HQL. For example the query is defined as a string. Strings are problematic because errors can't be detected at compile time. ICriteria queries go some way to alleviating this although they are certainly not perfect in this regard. You are writing tests against your repositories though aren't you? But the reliance on strings is not the only problem with HQL. Today I needed to create a search screen. I wanted to use a variation of the technique that Ayende demonstrates here. With HQL the repository methods become ugly very quickly (and I mean wake up sweating at 2 am ugly). There is a mass of conditional string concatenation. And for each parameter I need to change 2 pieces of code (the code that builds the HQL and the code that binds the parameters). So I decided to figure out how to use ICriteria to return a DTO. It transpires that the following code produces the same result as the HQL that I used before:

 

public List<InspectorDropDownDTO> GetAll()
{
 ICriteria q = session.CreateCriteria(typeof(Inspector), "i");
 q.CreateAlias("Person", "p");
 q.SetProjection(Projections.ProjectionList()
 .Add(Projections.Property("i.ID"), "InspectorID")
 .Add(Projections.Property("p.FirstName"), "FirstName")
 .Add(Projections.Property("p.LastName"), "LastName"));
 q.SetResultTransformer(Transformers.AliasToBean(typeof(InspectorDropDownDTO)));
 return q.List<InspectorDropDownDTO>();
}
It should be noted that the DTO itself is different with this method. A default constructor is now all that's needed because the AliasToBean transformer seems to work properly with ICriteria.

 

public class InspectorDropDownDTO
{
 private long _inspectorID;
 private string _firstName;
 private string _lastName;


 public long InspectorID { get { return _inspectorID; } set { _inspectorID = value; } }


 public string FirstName { get { return _firstName; } set { _firstName = value; } }


 public string LastName { get { return _lastName; } set { _lastName = value; } }


 public string FullName { get { return FirstName + " " + LastName; } }


}

Also note that you no longer need to import the DTO in an hbm.xml file.]]>
			http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/feed/
		2
		
		
		DTOs Simplify Complex Screens
	
	http://elegantcode.com
	
	Tue, 15 May 2012 10:00:00 +0000
	en
	hourly
	1
	http://wordpress.org/?v=3.3.1
		
		Elegant Code » NHibernate
	
	http://elegantcode.com
	
	Tue, 15 May 2012 10:00:00 +0000
	en
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		FubuMVC From Scratch – Part 4 Persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments
		Wed, 25 Mar 2009 21:22:00 +0000
		Ryan Kelley
				
		
		
		
		
		
		

		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/
		
			Previous posts in series:    
Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project
  
We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.
  
Class and Interfaces we have to implement: 
  
       
  • ISessionSourceConfiguration 
    •     
  • SQLServerSessionSourceConfiguration 
    •     
  • IUnitOfWork 
    •     
  • INHibernateUnitOfWork 
    •     
  • NHibernateUnitOfWork 
    •     
  • IRepository 
    •     
  • NHibernateRepository 
    •     
  • DomainEntity 
    •     
  • IDomainQuery 
    •     
  • FubuSamplePersistenceModel 
    •  
  
Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence
  
Before we start you probably want to go ahead and add the following references to your core project and Web project
  
FubuMVC-Persist-Ref 
  
Let’s just work our way down the list and get these files implemented. 
  
ISessionSourceConfiguration
  
   
     
public interface ISessionSourceConfiguration


    
{


    
    bool IsNewDatabase { get; }


    
    ISessionSource CreateSessionSource(PersistenceModel model);


    
}

  





SQLServerSessionSourceConfiguration




  

    
public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration


    
{


    
    #region Implementation of ISessionSourceConfiguration


    
 


    
    public bool IsNewDatabase


    
    {


    
        get { return false; }


    
    }


    
 


    
    public ISessionSource CreateSessionSource(PersistenceModel model)


    
    {


    
        var properties = GetProperties();


    
        var source = new SessionSource(properties, model);


    
 


    
        create_schema_if_it_does_not_already_exist(source);


    
 


    
        return source;


    
    }


    
 


    
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)


    
    {


    
        if (IsNewDatabase) source.BuildSchema();


    
    }


    
 


    
    protected IDictionary<string, string> GetProperties()


    
    {


    
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;


    
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);


    
        config.ShowSql();


    
        config.UseOuterJoin();


    
 


    
        return config.ToProperties();


    
    }


    
    #endregion


    
}

  





A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.



IUnitOfWork




  

    
public interface IUnitOfWork : IDisposable


    
{


    
    void Initialize();


    
    void Commit();


    
    void Rollback();


    
}

  





INHibernateUnitOfWork




  

    
public interface INHibernateUnitOfWork : IUnitOfWork


    
{


    
    ISession CurrentSession { get; }


    
}

  





NHibernateUnitOfWork




  

    
public class NHibernateUnitOfWork : INHibernateUnitOfWork


    
{


    
    private ITransaction _transaction;


    
    private bool _isDisposed;


    
    private readonly ISessionSource _source;


    
    private bool _isInitialized;


    
 


    
    public NHibernateUnitOfWork(ISessionSource source)


    
    {


    
        _source = source;


    
    }


    
 


    
    public void Initialize()


    
    {


    
        should_not_currently_be_disposed();


    
 


    
        CurrentSession = _source.CreateSession();


    
        begin_new_transaction();


    
 


    
        _isInitialized = true;


    
    }


    
 


    
    public ISession CurrentSession { get; private set; }


    
 


    
    public void Commit()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Commit();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void begin_new_transaction()


    
    {


    
        if (_transaction != null)


    
        {


    
            _transaction.Dispose();


    
        }


    
 


    
        _transaction = CurrentSession.BeginTransaction();


    
    }


    
 


    
    public void Rollback()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Rollback();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void should_not_currently_be_disposed()


    
    {


    
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);


    
    }


    
 


    
    private void should_be_initialized_first()


    
    {


    
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");


    
    }


    
 


    
    public void Dispose()


    
    {


    
        if (_isDisposed || !_isInitialized) return;


    
 


    
        _transaction.Dispose();


    
        CurrentSession.Dispose();


    
 


    
        _isDisposed = true;


    
    }


    
}

  





IRepository




  

    
public interface IRepository


    
{


    
    void Save<ENTITY>(ENTITY entity)


    
        where ENTITY : DomainEntity;


    
 


    
    ENTITY Load<ENTITY>(Guid id)


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>()


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)


    
        where ENTITY : DomainEntity;


    
 


    
    void Delete<ENTITY>(ENTITY entity);


    
 


    
    void DeleteAll<ENTITY>();


    
}

  





NHibernateRepository




  

    
public class NHibernateRepository : IRepository


    
{


    
    private readonly INHibernateUnitOfWork _unitOfWork;


    
 


    
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity


    
    {


    
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);


    
    }


    
 


    
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>();


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);


    
    }


    
 


    
    public void Delete<ENTITY>(ENTITY entity)


    
    {


    
        _unitOfWork.CurrentSession.Delete(entity);   


    
    }


    
 


    
    public void DeleteAll<ENTITY>()


    
    {


    
        var query = String.Format("from {0}", typeof(ENTITY).Name);


    
        _unitOfWork.CurrentSession.Delete(query);   


    
    }


    
}

  





DomainEntity



Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository




  

    
public class DomainEntity : IEquatable<DomainEntity>


    
{


    
    public virtual Guid ID { get; set; }


    
 


    
    public virtual bool Equals(DomainEntity other)


    
    {


    
        if (ReferenceEquals(null, other)) return false;


    
        if (ReferenceEquals(this, other)) return true;


    
        return other.ID.Equals(ID);


    
    }


    
 


    
    public override bool Equals(object obj)


    
    {


    
        if (ReferenceEquals(null, obj)) return false;


    
        if (ReferenceEquals(this, obj)) return true;


    
        if (obj.GetType() != GetType()) return false;


    
        return Equals((DomainEntity)obj);


    
    }


    
 


    
    public override int GetHashCode()


    
    {


    
        return ID.GetHashCode();


    
    }


    
 


    
    public static bool operator ==(DomainEntity left, DomainEntity right)


    
    {


    
        return Equals(left, right);


    
    }


    
 


    
    public static bool operator !=(DomainEntity left, DomainEntity right)


    
    {


    
        return !Equals(left, right);


    
    }


    
}

  





IDomainQuery




  

    
public interface IDomainQuery<ENTITY>


    
    where ENTITY : DomainEntity


    
{


    
    Expression<Func<ENTITY, bool>> Expression { get; }


    
}

  





FubuSamplePersistenceModel




  

    
namespace FubuSample.Core.Domain.Persistence


    
{


    
    public class FubuSamplePersistenceModel : PersistenceModel


    
    {


    
        public FubuSamplePersistenceModel()


    
        {


    
            addMappingsFromThisAssembly();


    
        }


    
    }


    
}

  





Now that we have all the puzzle pieces in place we need to hook them up and make them do some work. Open up FubuSampleWebRegistry 



And add the following code:




  

    
protected override void configure()


    
{


    
    ForRequestedType<ISessionSourceConfiguration>().AsSingletons()


    
        .TheDefault.Is.OfConcreteType<SQLServerSessionSourceConfiguration>();


    
 


    
 


    
    ForRequestedType<ISessionSource>().AsSingletons()


    
        .TheDefault.Is.ConstructedBy(ctx =>


    
                                     ctx.GetInstance<ISessionSourceConfiguration>()


    
                                         .CreateSessionSource(new FubuSamplePersistenceModel()));


    
 


    
    ForRequestedType<IUnitOfWork>().TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<INHibernateUnitOfWork>());


    
 


    
    ForRequestedType<INHibernateUnitOfWork>().CacheBy(InstanceScope.Hybrid)


    
        .TheDefault.Is.OfConcreteType<NHibernateUnitOfWork>();


    
 


    
    ForRequestedType<IRepository>().TheDefault.Is.OfConcreteType<NHibernateRepository>();


    
}

  





With a little luck and all of our mad skills, we should be able to talk to the database now. So we need to plumb our simple product object up to talk to NHibernate. We will do this with a mapping file, and since we are using FluentNHibernate we can do this strongly typed.



Make the following modifications to Product: Extend DomainEntity and get rid of Id Property, it is inherited




  

    
public class Product : DomainEntity


    
{


    
    public virtual string Name { get; set; }


    
    public virtual string Description { get; set; }


    
}

  





Add mapping file for Product:




  

    
namespace FubuSample.Core.Domain.Mapping


    
{


    
    public class ProductMap : ClassMap<Product>


    
    {


    
        public ProductMap()


    
        {


    
            Id(e => e.ID).GeneratedBy.GuidComb();


    
 


    
            Map(p => p.Name);


    
            Map(p => p.Description);


    
            


    
        }


    
    }


    
}

  





You may also want to setup your connection string at this point in the Web.Config file, mine looks like this:




  

    
<add name="MYDBKEY" connectionString="Data Source=LOCALHOST;initial catalog=FubuSample;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />

  





I also created an empty database in my local SQL Server instance called “FubuSample” And then I went back to SQLServerSessionSourceConfiguration and changed the value of IsNewDatabase to return true. This will create the schema for the database when the application first runs. There is a multitude of different ways that we can handle this, but this was easy for the tutorial purposes.



Next we will add a behavior to our core project and tell FubuMVC to apply that behavior to all or our ControllerActions.



Create a class named “access_the_database_through_a_unit_of_work” in your Core.Web.Behaviors namespace. The contents will look like this:




  

    
public class access_the_database_through_a_unit_of_work : IControllerActionBehavior


    
{


    
    private readonly IUnitOfWork _unitOfWork;


    
 


    
    public access_the_database_through_a_unit_of_work(IUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public IControllerActionBehavior InsideBehavior { get; set; }


    
    public IInvocationResult Result { get; set; }


    
 


    
    public OUTPUT Invoke<INPUT, OUTPUT>(INPUT input, Func<INPUT, OUTPUT> func)


    
        where INPUT : class


    
        where OUTPUT : class


    
    {


    
        _unitOfWork.Initialize();


    
 


    
        try


    
        {


    
            var output = InsideBehavior.Invoke(input, func);


    
            Result = InsideBehavior.Result;


    
 


    
            _unitOfWork.Commit();


    
 


    
            return output;


    
        }


    
        catch


    
        {


    
            _unitOfWork.Rollback();


    
            throw;


    
        }


    
        finally


    
        {


    
            _unitOfWork.Dispose();


    
        }


    
    }


    
}

  





Now to tell FubuMVC what to do, open up Global.asax.cs or your Bootstrapper, wherever you are doing the configuration of FubuMVC. In this project we are doing it in Global.asax.cs Add a new behavior to the section that starts with “x.ByDefault.EveryControllerAction” so it looks like this:




  

    
x.ByDefault.EveryControllerAction(d =>


    
   {


    
       d.Will<execute_the_result>();


    
       d.Will<access_the_database_through_a_unit_of_work>();


    
   });

  





The last thing we will do is open up HomeController and add this code above the Index action:




  

    
private IRepository _repository;


    
 


    
public HomeController(IRepository repository)


    
{


    
    _repository = repository;


    
}

  





I also modified the Index action to go ahead and create some database values before we query for them just so we can test this thing. (I only did this for the tutorial, I swear) So modify the Index action to look like this:




  

    
public IndexViewModel Index(IndexSetupViewModel inModel)


    
{


    
    var prod1 = new Product {Name = "TestProduct1", Description = "This is a test product"};


    
 


    
    _repository.Save(prod1);


    
 


    
    var prod2 = new Product {Name = "TestProduct2", Description = "This is a test product"};


    
 


    
    _repository.Save(prod2);


    
 


    
    var outModel = new IndexViewModel();


    
 


    
    var productList = _repository.Query<Product>();


    
 


    
    outModel.Products = productList.ToList().Select(x => new ProductDisplay(x));


    
 


    
    return outModel;


    
}

  





Now with you should be able to run your web app and browse to /home and all this will be executed and you will be on your way to creating a whole bunch of persist able objects for use with your FubuMVC app.



As always, feedback is welcome.
]]>
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		9
		
		
		Book review: NHibernate in Action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/?utm_source=rss&utm_medium=rss&utm_campaign=book-review-nhibernate-in-action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/#comments
		Sat, 14 Jun 2008 20:42:15 +0000
		Jan Van Ryswyck
				
		
		

		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/
		
			kuate_cover150 Writing this book review feels kind of weird  because it hasn't actually hit the shelves yet. It is accessible however through the Manning Early Access Program. This book provides a clear insight of using NHibernate as the data access layer of your applications and beyond. 
 
The excessive amount of NHibernate features  isn't the only thing that is written down. There is also a good coverage of OO principles and Domain-Driven Design, although it isn't the primary objective of the book of course. This is especially true for the first and the last three chapters. If you've already read the nominal books DDD and you are familiar with Persistence Ignorance, then you can safely skim through these chapters unless you want to see the interpretation of the authors when it comes to these principles. If you are new to these concepts, then these chapters are of great value to wet your appetite.
 
Although this book covers a lot of ground, I would certainly recommend it when you're rather new to NHibernate and ORM's in general. I guess this still includes me, although I've been using NHibernate for quite some time now. If you already have some experience with NHibernate, then this book probably doesn't teach you that much. Still, it can quickly get you up to speed when you want to use a particular feature that you haven't used before. 
 
The only minor thing about this book is that I'm afraid that it will soon be out-of-date. The book only covers NHibernate 1.2.x and no features from the upcoming 2.0 release, which adds a lot of new and interesting features. It would be nice if the book already covered some of these features as most of them are ported from Hibernate itself, which is the original Java version.
 
On the other hand, this book provides an in-depth view of the basic features of NHibernate, which aren't necessarily going to change that much over time anyway.
 
Let me round off this post by saying that I'm really impressed by the list of books that Manning is going to release the next couple of months. These are the ones that I'm particularly interested in:
  
I already bought LINQ in Action and also read a lot of good things about C# in Depth, which I'm going to pick up soon.
 
Take care.
]]>
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		7
		
		
		Integrating Castle Windsor and NHibernate with WCF
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/?utm_source=rss&utm_medium=rss&utm_campaign=integrating-castle-windsor-and-nhibernate-with-wcf
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/#comments
		Sun, 18 May 2008 14:08:20 +0000
		Jan Van Ryswyck
				
		

		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/
		
			Up until now, we were using the NHibernate facility of Castle Windsor for managing our NHibernate sessions in WCF. But, we want to have a session-per-request approach as one would use when integrating NHibernate with a regular web application. 
  
Yesterday I did a small spike to figure out how this should work. It turned out to be pretty easy. I used this excellent blog post written by Oran Dennison as my guide. 
  
First I created a class that implemented the IServiceBehavior interface.
  
   
public class DIServiceBehavior : IServiceBehavior
{
    private readonly ISessionFactory _sessionFactory;

    public DIServiceBehavior()
    {
        _sessionFactory = new Configuration()
            .Configure()
            .BuildSessionFactory();

        XmlConfigurator.Configure();    // Log4Net
    }

    public void ApplyDispatchBehavior(
             ServiceDescription serviceDescription, 
             ServiceHostBase serviceHostBase)
    {
        foreach(ChannelDispatcherBase cdb in 
                serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if(cd != null)
            {
                foreach(EndpointDispatcher ed in cd.Endpoints)
                {
                    ed.DispatchRuntime.InstanceProvider =
                        new DIInstanceProvider
                            (serviceDescription.ServiceType,
                              _sessionFactory);
                }
            }
        }
    }

    public void AddBindingParameters(
                ServiceDescription serviceDescription, 
                ServiceHostBase serviceHostBase,
                Collection<ServiceEndpoint> endpoints, 
                BindingParameterCollection bindingParameters) 
    { }
    
    public void Validate(ServiceDescription serviceDescription, 
                         ServiceHostBase serviceHostBase) 
    { }
}





The SessionFactory is created in the constructor because the ApplyDispatchBehaviour method can be called multiple times (for each endpoint). 



The next step is to create an instance provider by creating a class that implements the IInstanceProvider:




  
public class DIInstanceProvider : IInstanceProvider
{
    private const String NHibernateSessionKey = 
        "NHibernate.Session";

    private readonly Type _serviceType;
    private IDependencyContainer _dependencyContainer;
    private readonly ISessionFactory _sessionFactory;
    private ISession _session;

    public DIInstanceProvider(Type serviceType,
                               ISessionFactory sessionFactory)
    {
        Debug.Assert(null != serviceType, 
                     "null != serviceType");
        _serviceType = serviceType;

        Debug.Assert(null != sessionFactory, 
                     "null = sessionFactory");
        _sessionFactory = sessionFactory;
    }

    public Object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public Object GetInstance(InstanceContext instanceContext, 
                                Message message)
    {
        _dependencyContainer = new DependencyContainer();

        _session = _sessionFactory.OpenSession();
        _dependencyContainer
          .AddComponentInstance(NHibernateSessionKey, _session);

        return _dependencyContainer.Resolve(_serviceType);
    }

    public void ReleaseInstance(InstanceContext instanceContext, 
                                 Object instance)
    {
        if(null != _session)
        {
            _session.Close();
            _session = null;
        }

        if(null != _dependencyContainer)
        {
            _dependencyContainer.Dispose();
            _dependencyContainer = null;
        }
    }
}





I created a wrapper class around for Castle Windsor named DependencyContainer.  The GetInstance method opens a new session using the SessionFactory object we instantiated in the service behavior class. The session object is then registered with Castle Windsor. We can now implement our repositories like this:




  
public class SomeAggregateRepository
{
    private ISession _session;

    public SomeAggregateRepository(ISession session)
    {
        _session = session;
    }
    
    public SomeAggregate Get(Int64 id) 
    {
        return _session.Get<SomeAggregate>(id);
    }
}





When our service operation has been executed, the NHibernate is released by the ReleaseInstance method. Finishing our example, we need to implement a custom ServiceHost and a ServiceHostFactory:




  
public class DIServiceHost : ServiceHost
{
    public DependencyInjectionServiceHost() 
        : base() 
    { }
    
    public DIServiceHost(Type serviceType, 
                         params Uri[] baseAddresses) 
        : base(serviceType, baseAddresses) 
    { }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new DIServiceBehavior());
        base.OnOpening();
    }
}

public class DIServiceHostFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(
            Type serviceType, Uri[] baseAddresses)
    {
        return new DIServiceHost(serviceType, baseAddresses);
    }
}





The custom ServiceHostFactory class can now be used in the ServiceHost file required when doing IIS hosting:




  
<%@ ServiceHost Language="C#" 
                Debug="true" 
                Service="WindsorService.MyWindsorService" 
                Factory="WindsorService.DIServiceHostFactory"
                CodeBehind="MyWindsorService.svc.cs" %>





There is also another way for achieving this that I will be investigating the next week or so using the WCF Integration Facility for Castle Windsor. For some reason it is not available in the current release of the Castle stack so I have to grab it from the trunk. 



If you have any thoughts, improvements or suggestions I'm glad to hear them from you, my dear reader. It's the only way I'll ever learn :-). 



Till next time.
]]>
			http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/feed/
		9
		
		
		Implementing NHibernate Interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/?utm_source=rss&utm_medium=rss&utm_campaign=implementing-nhibernate-interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/#comments
		Thu, 15 May 2008 18:29:26 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/
		
			One of the areas where NHibernate really shines is it's high extensibility features. The NHibernate API provides a massive amount of interfaces that can be implemented for your own custom extension pleasure. 
  
For me this is a nice change as opposed to the many sealed API's put out by the Redmond collective (WCF being the exception, the Entity Framework confirming the rule).
  
Anyhow, with great power comes great responsibility. Today I encountered a rather difficult problem with NHibernate that could have been easily prevented by reading the documentation (note to self: use the CTRL-Q shortcut of Resharper more often).
  
We have implemented an interceptor for automatically configuring audit information as described by this great post from Ray Houston. 
  
   
public class AuditInformationInterceptor 
    : EmptyInterceptor
{
    Boolean OnSave(Object entity, Object id, Object[] state, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }

    Boolean OnFlushDirty(Object entity, Object id, 
        Object[] currentState, Object[] previousState, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }                  
}





The mistake we made is that we manipulated the audit information of the entity directly in the OnSave and OnFlushDirty methods. This only became apparent when saving an aggregate root with his child entities. Everything worked fine until we wanted to persist one of the child entities that should have been a piece of cake but turned out to be the messenger of trouble. NHibernate refused to perform an INSERT statement, but instead threw an UPDATE statement at us. 



After some debugging we found out that the audit information should have been manipulated through the state and currentState arguments of the OnSave and OnFlushDirty methods respectively.



The documentation of the OnSave method clearly states:



The interceptor may modify the state, which will be used for the SQL INSERT

    
and propagated to the persistent object



Lesson relearned. 



I'm off, reading some docs. Until next time.
]]>
			http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/feed/
		3
		
		
		On Persistence
		http://elegantcode.com/2008/05/01/on-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=on-persistence
		http://elegantcode.com/2008/05/01/on-persistence/#comments
		Thu, 01 May 2008 19:18:43 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/01/on-persistence/
		
			Earlier this week, I managed to convince our very wise decision makers to start using NHibernate for our persistence layer. My team mate on the project describes how it went. While I was reading Jeremy's train of thoughts, the following four lines made me realize we did the right thing:
  
Why are teams still writing persistence code by hand?  There's a bazillion persistence tools out there that all save development costs in some way over writing data access code by hand.  With very few exceptions, I'd say that at this point that if you're writing ADO.Net code or SQL by hand, you're stealing money from your employer.  
  
As another co-worker and NHibernate fan thoughtfully mentioned while congratulating us:
  
A small step for man, but a giant leap for mankind.
  
Few. What a week this turns out to be.
]]>
			http://elegantcode.com/2008/05/01/on-persistence/feed/
		2
		
		
		NHibernate 2.0 and Cascading Deletes
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-20-and-cascading-deletes-2
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/#comments
		Sat, 12 Apr 2008 18:58:12 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/
		
			The first alpha version of NHibernate 2.0 has been released some time ago. Oren has put a nice overview of the new features and the bugs that are solved for this first drop. In spite the fact that they put the word 'alpha' in the version name, it is actually RTM quality! 
  
One of the great new additions is the on-delete attribute of the key element for mapping collections:
  
<set name="Permissions" inverse="true" cascade="save-update">
  <key name="Authorization" on-delete="cascade"/>
  <one-to-many class="Permission"/>
</set>



This particular feature solves the issue I've had with one-shot deletes on inverse collections (which I described here). Configuring it this way ensures that NHibernate relies on database-level ON CASCADE DELETE foreign key constraints. This implies that when an object with a collection of child objects is deleted, a single DELETE  statement is used to remove all children at once instead of individual DELETE statements for each child object (which are called orphans at this point).



There are some things that you have to take into account here. First, this option bypasses NHibernate's optimistic locking strategy for versioned data. Second, make sure that you configure cascade="save-update" instead of cascade="all" to prevent NHibernate from performing delete cascade checks. This is important when lazy loading is enabled for the collection because it prevents that NHibernate loads one-to-many associations into memory. 



I'm really excited about this new release. Kudos to the men and women who have put so much effort in building such a wonderful ORM solution!



Till next time
]]>
			http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/feed/
		0
		
		
		A New NHibernate Blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/?utm_source=rss&utm_medium=rss&utm_campaign=a-new-nhibernate-blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/#comments
		Tue, 01 Apr 2008 15:26:32 +0000
		Alex Mueller
				
		
		
		

		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/
		
			Craig Neuwirt recently started a blog focused on NHibernate, as mentioned by Ayende. NHibernate is an ORM tool I have used on current and past projects and it is something I feel I would like I want to study further. So far, Craig is walking us through NHibernate from the ground-up, with the latest and greatest. I anticipate this being an informative blog to follow.

The NHibernate FAQ
Craig Neuwirt
Hibernating Rhinos]]>
			http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/feed/
		2
		
		
		NHibernate IQuery to ISQLQuery Black Magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-iquery-to-isqlquery-black-magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/#comments
		Fri, 16 Nov 2007 06:12:55 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/
		
			posted on the forums and learned that: I'd run into a known bug / limitation.

Therefore I resorted to using ISQLQuery (yuk). I fixed several repository methods and then I ran into a very complicated IQuery. It was very painful to write the first time. In fact it was this experience that had caused me to change to using ICriteria as my default query method with specifications. I had a full suite of unit tests to protect me so I was confident that I could make the changes without breaking anything but I didn't want to do the conversion manually. Surely there was a trick?

It turns out that there is - NHibernate.Hql.Classic.QueryTranslator. The property that I needed is protected but thanks to a quick search of the forums I didn't even need to write my own reflection based method of calling it because someone had done it for me (thanks Nels). So what I did was take the HQL and convert it to SQL. I then did some string replacement to morph the SQL into what I needed. I am not proud of this but it was fast and it goes to show for flexible NHibernate is if you want to do some certifiable things.]]>
			http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/feed/
		0
		
		
		DTOs / Presentation Model and ICriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/?utm_source=rss&utm_medium=rss&utm_campaign=dtos-presentation-model-and-icriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/#comments
		Tue, 06 Nov 2007 06:11:41 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/
		
			NHibernate Projections I used HQL (IQuery) in the repository to define the query.

There are a some things that I don't like about HQL. For example the query is defined as a string. Strings are problematic because errors can't be detected at compile time. ICriteria queries go some way to alleviating this although they are certainly not perfect in this regard. You are writing tests against your repositories though aren't you?

But the reliance on strings is not the only problem with HQL. Today I needed to create a search screen. I wanted to use a variation of the technique that Ayende demonstrates here. With HQL the repository methods become ugly very quickly (and I mean wake up sweating at 2 am ugly). There is a mass of conditional string concatenation. And for each parameter I need to change 2 pieces of code (the code that builds the HQL and the code that binds the parameters).

So I decided to figure out how to use ICriteria to return a DTO. It transpires that the following code produces the same result as the HQL that I used before:

 



public List<InspectorDropDownDTO> GetAll()


{


 ICriteria q = session.CreateCriteria(typeof(Inspector), "i");


 q.CreateAlias("Person", "p");


 q.SetProjection(Projections.ProjectionList()


 .Add(Projections.Property("i.ID"), "InspectorID")


 .Add(Projections.Property("p.FirstName"), "FirstName")


 .Add(Projections.Property("p.LastName"), "LastName"));


 q.SetResultTransformer(Transformers.AliasToBean(typeof(InspectorDropDownDTO)));


 return q.List<InspectorDropDownDTO>();


}

It should be noted that the DTO itself is different with this method. A default constructor is now all that's needed because the AliasToBean transformer seems to work properly with ICriteria.

 



public class InspectorDropDownDTO


{


 private long _inspectorID;


 private string _firstName;


 private string _lastName;




 public long InspectorID { get { return _inspectorID; } set { _inspectorID = value; } }


 public string FirstName { get { return _firstName; } set { _firstName = value; } }


 public string LastName { get { return _lastName; } set { _lastName = value; } }


 public string FullName { get { return FirstName + " " + LastName; } }


}

Also note that you no longer need to import the DTO in an hbm.xml file.]]>
			http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/feed/
		2
		
		
		DTOs Simplify Complex Screens
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments
		Wed, 25 Mar 2009 21:22:00 +0000
		Ryan Kelley
				
		
		
		
		
		
		

		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/
		
			Previous posts in series:    
Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project
  
We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.
  
Class and Interfaces we have to implement: 
  
       
  • ISessionSourceConfiguration 
    •     
  • SQLServerSessionSourceConfiguration 
    •     
  • IUnitOfWork 
    •     
  • INHibernateUnitOfWork 
    •     
  • NHibernateUnitOfWork 
    •     
  • IRepository 
    •     
  • NHibernateRepository 
    •     
  • DomainEntity 
    •     
  • IDomainQuery 
    •     
  • FubuSamplePersistenceModel 
    •  
  
Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence
  
Before we start you probably want to go ahead and add the following references to your core project and Web project
  
FubuMVC-Persist-Ref 
  
Let’s just work our way down the list and get these files implemented. 
  
ISessionSourceConfiguration
  
   
     
public interface ISessionSourceConfiguration


    
{


    
    bool IsNewDatabase { get; }


    
    ISessionSource CreateSessionSource(PersistenceModel model);


    
}

  





SQLServerSessionSourceConfiguration




  

    
public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration


    
{


    
    #region Implementation of ISessionSourceConfiguration


    
 


    
    public bool IsNewDatabase


    
    {


    
        get { return false; }


    
    }


    
 


    
    public ISessionSource CreateSessionSource(PersistenceModel model)


    
    {


    
        var properties = GetProperties();


    
        var source = new SessionSource(properties, model);


    
 


    
        create_schema_if_it_does_not_already_exist(source);


    
 


    
        return source;


    
    }


    
 


    
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)


    
    {


    
        if (IsNewDatabase) source.BuildSchema();


    
    }


    
 


    
    protected IDictionary<string, string> GetProperties()


    
    {


    
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;


    
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);


    
        config.ShowSql();


    
        config.UseOuterJoin();


    
 


    
        return config.ToProperties();


    
    }


    
    #endregion


    
}

  





A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.



IUnitOfWork




  

    
public interface IUnitOfWork : IDisposable


    
{


    
    void Initialize();


    
    void Commit();


    
    void Rollback();


    
}

  





INHibernateUnitOfWork




  

    
public interface INHibernateUnitOfWork : IUnitOfWork


    
{


    
    ISession CurrentSession { get; }


    
}

  





NHibernateUnitOfWork




  

    
public class NHibernateUnitOfWork : INHibernateUnitOfWork


    
{


    
    private ITransaction _transaction;


    
    private bool _isDisposed;


    
    private readonly ISessionSource _source;


    
    private bool _isInitialized;


    
 


    
    public NHibernateUnitOfWork(ISessionSource source)


    
    {


    
        _source = source;


    
    }


    
 


    
    public void Initialize()


    
    {


    
        should_not_currently_be_disposed();


    
 


    
        CurrentSession = _source.CreateSession();


    
        begin_new_transaction();


    
 


    
        _isInitialized = true;


    
    }


    
 


    
    public ISession CurrentSession { get; private set; }


    
 


    
    public void Commit()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Commit();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void begin_new_transaction()


    
    {


    
        if (_transaction != null)


    
        {


    
            _transaction.Dispose();


    
        }


    
 


    
        _transaction = CurrentSession.BeginTransaction();


    
    }


    
 


    
    public void Rollback()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Rollback();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void should_not_currently_be_disposed()


    
    {


    
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);


    
    }


    
 


    
    private void should_be_initialized_first()


    
    {


    
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");


    
    }


    
 


    
    public void Dispose()


    
    {


    
        if (_isDisposed || !_isInitialized) return;


    
 


    
        _transaction.Dispose();


    
        CurrentSession.Dispose();


    
 


    
        _isDisposed = true;


    
    }


    
}

  





IRepository




  

    
public interface IRepository


    
{


    
    void Save<ENTITY>(ENTITY entity)


    
        where ENTITY : DomainEntity;


    
 


    
    ENTITY Load<ENTITY>(Guid id)


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>()


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)


    
        where ENTITY : DomainEntity;


    
 


    
    void Delete<ENTITY>(ENTITY entity);


    
 


    
    void DeleteAll<ENTITY>();


    
}

  





NHibernateRepository




  

    
public class NHibernateRepository : IRepository


    
{


    
    private readonly INHibernateUnitOfWork _unitOfWork;


    
 


    
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity


    
    {


    
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);


    
    }


    
 


    
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>();


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);


    
    }


    
 


    
    public void Delete<ENTITY>(ENTITY entity)


    
    {


    
        _unitOfWork.CurrentSession.Delete(entity);   


    
    }


    
 


    
    public void DeleteAll<ENTITY>()


    
    {


    
        var query = String.Format("from {0}", typeof(ENTITY).Name);


    
        _unitOfWork.CurrentSession.Delete(query);   


    
    }


    
}

  





DomainEntity



Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository




  

    
public class DomainEntity : IEquatable<DomainEntity>


    
{


    
    public virtual Guid ID { get; set; }


    
 


    
    public virtual bool Equals(DomainEntity other)


    
    {


    
        if (ReferenceEquals(null, other)) return false;


    
        if (ReferenceEquals(this, other)) return true;


    
        return other.ID.Equals(ID);


    
    }


    
 


    
    public override bool Equals(object obj)


    
    {


    
        if (ReferenceEquals(null, obj)) return false;


    
        if (ReferenceEquals(this, obj)) return true;


    
        if (obj.GetType() != GetType()) return false;


    
        return Equals((DomainEntity)obj);


    
    }


    
 


    
    public override int GetHashCode()


    
    {


    
        return ID.GetHashCode();


    
    }


    
 


    
    public static bool operator ==(DomainEntity left, DomainEntity right)


    
    {


    
        return Equals(left, right);


    
    }


    
 


    
    public static bool operator !=(DomainEntity left, DomainEntity right)


    
    {


    
        return !Equals(left, right);


    
    }


    
}

  





IDomainQuery




  

    
public interface IDomainQuery<ENTITY>


    
    where ENTITY : DomainEntity


    
{


    
    Expression<Func<ENTITY, bool>> Expression { get; }


    
}

  





FubuSamplePersistenceModel




  

    
namespace FubuSample.Core.Domain.Persistence


    
{


    
    public class FubuSamplePersistenceModel : PersistenceModel


    
    {


    
        public FubuSamplePersistenceModel()


    
        {


    
            addMappingsFromThisAssembly();


    
        }


    
    }


    
}

  





Now that we have all the puzzle pieces in place we need to hook them up and make them do some work. Open up FubuSampleWebRegistry 



And add the following code:




  

    
protected override void configure()


    
{


    
    ForRequestedType<ISessionSourceConfiguration>().AsSingletons()


    
        .TheDefault.Is.OfConcreteType<SQLServerSessionSourceConfiguration>();


    
 


    
 


    
    ForRequestedType<ISessionSource>().AsSingletons()


    
        .TheDefault.Is.ConstructedBy(ctx =>


    
                                     ctx.GetInstance<ISessionSourceConfiguration>()


    
                                         .CreateSessionSource(new FubuSamplePersistenceModel()));


    
 


    
    ForRequestedType<IUnitOfWork>().TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<INHibernateUnitOfWork>());


    
 


    
    ForRequestedType<INHibernateUnitOfWork>().CacheBy(InstanceScope.Hybrid)


    
        .TheDefault.Is.OfConcreteType<NHibernateUnitOfWork>();


    
 


    
    ForRequestedType<IRepository>().TheDefault.Is.OfConcreteType<NHibernateRepository>();


    
}

  





With a little luck and all of our mad skills, we should be able to talk to the database now. So we need to plumb our simple product object up to talk to NHibernate. We will do this with a mapping file, and since we are using FluentNHibernate we can do this strongly typed.



Make the following modifications to Product: Extend DomainEntity and get rid of Id Property, it is inherited




  

    
public class Product : DomainEntity


    
{


    
    public virtual string Name { get; set; }


    
    public virtual string Description { get; set; }


    
}

  





Add mapping file for Product:




  

    
namespace FubuSample.Core.Domain.Mapping


    
{


    
    public class ProductMap : ClassMap<Product>


    
    {


    
        public ProductMap()


    
        {


    
            Id(e => e.ID).GeneratedBy.GuidComb();


    
 


    
            Map(p => p.Name);


    
            Map(p => p.Description);


    
            


    
        }


    
    }


    
}

  





You may also want to setup your connection string at this point in the Web.Config file, mine looks like this:




  

    
<add name="MYDBKEY" connectionString="Data Source=LOCALHOST;initial catalog=FubuSample;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />

  





I also created an empty database in my local SQL Server instance called “FubuSample” And then I went back to SQLServerSessionSourceConfiguration and changed the value of IsNewDatabase to return true. This will create the schema for the database when the application first runs. There is a multitude of different ways that we can handle this, but this was easy for the tutorial purposes.



Next we will add a behavior to our core project and tell FubuMVC to apply that behavior to all or our ControllerActions.



Create a class named “access_the_database_through_a_unit_of_work” in your Core.Web.Behaviors namespace. The contents will look like this:




  

    
public class access_the_database_through_a_unit_of_work : IControllerActionBehavior


    
{


    
    private readonly IUnitOfWork _unitOfWork;


    
 


    
    public access_the_database_through_a_unit_of_work(IUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public IControllerActionBehavior InsideBehavior { get; set; }


    
    public IInvocationResult Result { get; set; }


    
 


    
    public OUTPUT Invoke<INPUT, OUTPUT>(INPUT input, Func<INPUT, OUTPUT> func)


    
        where INPUT : class


    
        where OUTPUT : class


    
    {


    
        _unitOfWork.Initialize();


    
 


    
        try


    
        {


    
            var output = InsideBehavior.Invoke(input, func);


    
            Result = InsideBehavior.Result;


    
 


    
            _unitOfWork.Commit();


    
 


    
            return output;


    
        }


    
        catch


    
        {


    
            _unitOfWork.Rollback();


    
            throw;


    
        }


    
        finally


    
        {


    
            _unitOfWork.Dispose();


    
        }


    
    }


    
}

  





Now to tell FubuMVC what to do, open up Global.asax.cs or your Bootstrapper, wherever you are doing the configuration of FubuMVC. In this project we are doing it in Global.asax.cs Add a new behavior to the section that starts with “x.ByDefault.EveryControllerAction” so it looks like this:




  

    
x.ByDefault.EveryControllerAction(d =>


    
   {


    
       d.Will<execute_the_result>();


    
       d.Will<access_the_database_through_a_unit_of_work>();


    
   });

  





The last thing we will do is open up HomeController and add this code above the Index action:




  

    
private IRepository _repository;


    
 


    
public HomeController(IRepository repository)


    
{


    
    _repository = repository;


    
}

  





I also modified the Index action to go ahead and create some database values before we query for them just so we can test this thing. (I only did this for the tutorial, I swear) So modify the Index action to look like this:




  

    
public IndexViewModel Index(IndexSetupViewModel inModel)


    
{


    
    var prod1 = new Product {Name = "TestProduct1", Description = "This is a test product"};


    
 


    
    _repository.Save(prod1);


    
 


    
    var prod2 = new Product {Name = "TestProduct2", Description = "This is a test product"};


    
 


    
    _repository.Save(prod2);


    
 


    
    var outModel = new IndexViewModel();


    
 


    
    var productList = _repository.Query<Product>();


    
 


    
    outModel.Products = productList.ToList().Select(x => new ProductDisplay(x));


    
 


    
    return outModel;


    
}

  





Now with you should be able to run your web app and browse to /home and all this will be executed and you will be on your way to creating a whole bunch of persist able objects for use with your FubuMVC app.



As always, feedback is welcome.
]]>
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		9
		
		
		Elegant Code » NHibernate
	
	http://elegantcode.com
	
	Tue, 15 May 2012 10:00:00 +0000
	en
	hourly
	1
	http://wordpress.org/?v=3.3.1
		
		FubuMVC From Scratch – Part 4 Persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments
		Wed, 25 Mar 2009 21:22:00 +0000
		Ryan Kelley
				
		
		
		
		
		
		

		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/
		
			Previous posts in series:    
Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project
  
We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.
  
Class and Interfaces we have to implement: 
  
       
  • ISessionSourceConfiguration 
    •     
  • SQLServerSessionSourceConfiguration 
    •     
  • IUnitOfWork 
    •     
  • INHibernateUnitOfWork 
    •     
  • NHibernateUnitOfWork 
    •     
  • IRepository 
    •     
  • NHibernateRepository 
    •     
  • DomainEntity 
    •     
  • IDomainQuery 
    •     
  • FubuSamplePersistenceModel 
    •  
  
Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence
  
Before we start you probably want to go ahead and add the following references to your core project and Web project
  
FubuMVC-Persist-Ref 
  
Let’s just work our way down the list and get these files implemented. 
  
ISessionSourceConfiguration
  
   
     
public interface ISessionSourceConfiguration


    
{


    
    bool IsNewDatabase { get; }


    
    ISessionSource CreateSessionSource(PersistenceModel model);


    
}

  





SQLServerSessionSourceConfiguration




  

    
public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration


    
{


    
    #region Implementation of ISessionSourceConfiguration


    
 


    
    public bool IsNewDatabase


    
    {


    
        get { return false; }


    
    }


    
 


    
    public ISessionSource CreateSessionSource(PersistenceModel model)


    
    {


    
        var properties = GetProperties();


    
        var source = new SessionSource(properties, model);


    
 


    
        create_schema_if_it_does_not_already_exist(source);


    
 


    
        return source;


    
    }


    
 


    
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)


    
    {


    
        if (IsNewDatabase) source.BuildSchema();


    
    }


    
 


    
    protected IDictionary<string, string> GetProperties()


    
    {


    
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;


    
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);


    
        config.ShowSql();


    
        config.UseOuterJoin();


    
 


    
        return config.ToProperties();


    
    }


    
    #endregion


    
}

  





A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.



IUnitOfWork




  

    
public interface IUnitOfWork : IDisposable


    
{


    
    void Initialize();


    
    void Commit();


    
    void Rollback();


    
}

  





INHibernateUnitOfWork




  

    
public interface INHibernateUnitOfWork : IUnitOfWork


    
{


    
    ISession CurrentSession { get; }


    
}

  





NHibernateUnitOfWork




  

    
public class NHibernateUnitOfWork : INHibernateUnitOfWork


    
{


    
    private ITransaction _transaction;


    
    private bool _isDisposed;


    
    private readonly ISessionSource _source;


    
    private bool _isInitialized;


    
 


    
    public NHibernateUnitOfWork(ISessionSource source)


    
    {


    
        _source = source;


    
    }


    
 


    
    public void Initialize()


    
    {


    
        should_not_currently_be_disposed();


    
 


    
        CurrentSession = _source.CreateSession();


    
        begin_new_transaction();


    
 


    
        _isInitialized = true;


    
    }


    
 


    
    public ISession CurrentSession { get; private set; }


    
 


    
    public void Commit()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Commit();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void begin_new_transaction()


    
    {


    
        if (_transaction != null)


    
        {


    
            _transaction.Dispose();


    
        }


    
 


    
        _transaction = CurrentSession.BeginTransaction();


    
    }


    
 


    
    public void Rollback()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Rollback();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void should_not_currently_be_disposed()


    
    {


    
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);


    
    }


    
 


    
    private void should_be_initialized_first()


    
    {


    
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");


    
    }


    
 


    
    public void Dispose()


    
    {


    
        if (_isDisposed || !_isInitialized) return;


    
 


    
        _transaction.Dispose();


    
        CurrentSession.Dispose();


    
 


    
        _isDisposed = true;


    
    }


    
}

  





IRepository




  

    
public interface IRepository


    
{


    
    void Save<ENTITY>(ENTITY entity)


    
        where ENTITY : DomainEntity;


    
 


    
    ENTITY Load<ENTITY>(Guid id)


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>()


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)


    
        where ENTITY : DomainEntity;


    
 


    
    void Delete<ENTITY>(ENTITY entity);


    
 


    
    void DeleteAll<ENTITY>();


    
}

  





NHibernateRepository




  

    
public class NHibernateRepository : IRepository


    
{


    
    private readonly INHibernateUnitOfWork _unitOfWork;


    
 


    
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity


    
    {


    
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);


    
    }


    
 


    
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>();


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);


    
    }


    
 


    
    public void Delete<ENTITY>(ENTITY entity)


    
    {


    
        _unitOfWork.CurrentSession.Delete(entity);   


    
    }


    
 


    
    public void DeleteAll<ENTITY>()


    
    {


    
        var query = String.Format("from {0}", typeof(ENTITY).Name);


    
        _unitOfWork.CurrentSession.Delete(query);   


    
    }


    
}

  





DomainEntity



Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository




  

    
public class DomainEntity : IEquatable<DomainEntity>


    
{


    
    public virtual Guid ID { get; set; }


    
 


    
    public virtual bool Equals(DomainEntity other)


    
    {


    
        if (ReferenceEquals(null, other)) return false;


    
        if (ReferenceEquals(this, other)) return true;


    
        return other.ID.Equals(ID);


    
    }


    
 


    
    public override bool Equals(object obj)


    
    {


    
        if (ReferenceEquals(null, obj)) return false;


    
        if (ReferenceEquals(this, obj)) return true;


    
        if (obj.GetType() != GetType()) return false;


    
        return Equals((DomainEntity)obj);


    
    }


    
 


    
    public override int GetHashCode()


    
    {


    
        return ID.GetHashCode();


    
    }


    
 


    
    public static bool operator ==(DomainEntity left, DomainEntity right)


    
    {


    
        return Equals(left, right);


    
    }


    
 


    
    public static bool operator !=(DomainEntity left, DomainEntity right)


    
    {


    
        return !Equals(left, right);


    
    }


    
}

  





IDomainQuery




  

    
public interface IDomainQuery<ENTITY>


    
    where ENTITY : DomainEntity


    
{


    
    Expression<Func<ENTITY, bool>> Expression { get; }


    
}

  





FubuSamplePersistenceModel




  

    
namespace FubuSample.Core.Domain.Persistence


    
{


    
    public class FubuSamplePersistenceModel : PersistenceModel


    
    {


    
        public FubuSamplePersistenceModel()


    
        {


    
            addMappingsFromThisAssembly();


    
        }


    
    }


    
}

  





Now that we have all the puzzle pieces in place we need to hook them up and make them do some work. Open up FubuSampleWebRegistry 



And add the following code:




  

    
protected override void configure()


    
{


    
    ForRequestedType<ISessionSourceConfiguration>().AsSingletons()


    
        .TheDefault.Is.OfConcreteType<SQLServerSessionSourceConfiguration>();


    
 


    
 


    
    ForRequestedType<ISessionSource>().AsSingletons()


    
        .TheDefault.Is.ConstructedBy(ctx =>


    
                                     ctx.GetInstance<ISessionSourceConfiguration>()


    
                                         .CreateSessionSource(new FubuSamplePersistenceModel()));


    
 


    
    ForRequestedType<IUnitOfWork>().TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<INHibernateUnitOfWork>());


    
 


    
    ForRequestedType<INHibernateUnitOfWork>().CacheBy(InstanceScope.Hybrid)


    
        .TheDefault.Is.OfConcreteType<NHibernateUnitOfWork>();


    
 


    
    ForRequestedType<IRepository>().TheDefault.Is.OfConcreteType<NHibernateRepository>();


    
}

  





With a little luck and all of our mad skills, we should be able to talk to the database now. So we need to plumb our simple product object up to talk to NHibernate. We will do this with a mapping file, and since we are using FluentNHibernate we can do this strongly typed.



Make the following modifications to Product: Extend DomainEntity and get rid of Id Property, it is inherited




  

    
public class Product : DomainEntity


    
{


    
    public virtual string Name { get; set; }


    
    public virtual string Description { get; set; }


    
}

  





Add mapping file for Product:




  

    
namespace FubuSample.Core.Domain.Mapping


    
{


    
    public class ProductMap : ClassMap<Product>


    
    {


    
        public ProductMap()


    
        {


    
            Id(e => e.ID).GeneratedBy.GuidComb();


    
 


    
            Map(p => p.Name);


    
            Map(p => p.Description);


    
            


    
        }


    
    }


    
}

  





You may also want to setup your connection string at this point in the Web.Config file, mine looks like this:




  

    
<add name="MYDBKEY" connectionString="Data Source=LOCALHOST;initial catalog=FubuSample;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />

  





I also created an empty database in my local SQL Server instance called “FubuSample” And then I went back to SQLServerSessionSourceConfiguration and changed the value of IsNewDatabase to return true. This will create the schema for the database when the application first runs. There is a multitude of different ways that we can handle this, but this was easy for the tutorial purposes.



Next we will add a behavior to our core project and tell FubuMVC to apply that behavior to all or our ControllerActions.



Create a class named “access_the_database_through_a_unit_of_work” in your Core.Web.Behaviors namespace. The contents will look like this:




  

    
public class access_the_database_through_a_unit_of_work : IControllerActionBehavior


    
{


    
    private readonly IUnitOfWork _unitOfWork;


    
 


    
    public access_the_database_through_a_unit_of_work(IUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public IControllerActionBehavior InsideBehavior { get; set; }


    
    public IInvocationResult Result { get; set; }


    
 


    
    public OUTPUT Invoke<INPUT, OUTPUT>(INPUT input, Func<INPUT, OUTPUT> func)


    
        where INPUT : class


    
        where OUTPUT : class


    
    {


    
        _unitOfWork.Initialize();


    
 


    
        try


    
        {


    
            var output = InsideBehavior.Invoke(input, func);


    
            Result = InsideBehavior.Result;


    
 


    
            _unitOfWork.Commit();


    
 


    
            return output;


    
        }


    
        catch


    
        {


    
            _unitOfWork.Rollback();


    
            throw;


    
        }


    
        finally


    
        {


    
            _unitOfWork.Dispose();


    
        }


    
    }


    
}

  





Now to tell FubuMVC what to do, open up Global.asax.cs or your Bootstrapper, wherever you are doing the configuration of FubuMVC. In this project we are doing it in Global.asax.cs Add a new behavior to the section that starts with “x.ByDefault.EveryControllerAction” so it looks like this:




  

    
x.ByDefault.EveryControllerAction(d =>


    
   {


    
       d.Will<execute_the_result>();


    
       d.Will<access_the_database_through_a_unit_of_work>();


    
   });

  





The last thing we will do is open up HomeController and add this code above the Index action:




  

    
private IRepository _repository;


    
 


    
public HomeController(IRepository repository)


    
{


    
    _repository = repository;


    
}

  





I also modified the Index action to go ahead and create some database values before we query for them just so we can test this thing. (I only did this for the tutorial, I swear) So modify the Index action to look like this:




  

    
public IndexViewModel Index(IndexSetupViewModel inModel)


    
{


    
    var prod1 = new Product {Name = "TestProduct1", Description = "This is a test product"};


    
 


    
    _repository.Save(prod1);


    
 


    
    var prod2 = new Product {Name = "TestProduct2", Description = "This is a test product"};


    
 


    
    _repository.Save(prod2);


    
 


    
    var outModel = new IndexViewModel();


    
 


    
    var productList = _repository.Query<Product>();


    
 


    
    outModel.Products = productList.ToList().Select(x => new ProductDisplay(x));


    
 


    
    return outModel;


    
}

  





Now with you should be able to run your web app and browse to /home and all this will be executed and you will be on your way to creating a whole bunch of persist able objects for use with your FubuMVC app.



As always, feedback is welcome.
]]>
			http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/feed/
		9
		
		
		Book review: NHibernate in Action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/?utm_source=rss&utm_medium=rss&utm_campaign=book-review-nhibernate-in-action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/#comments
		Sat, 14 Jun 2008 20:42:15 +0000
		Jan Van Ryswyck
				
		
		

		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/
		
			kuate_cover150 Writing this book review feels kind of weird  because it hasn't actually hit the shelves yet. It is accessible however through the Manning Early Access Program. This book provides a clear insight of using NHibernate as the data access layer of your applications and beyond. 
 
The excessive amount of NHibernate features  isn't the only thing that is written down. There is also a good coverage of OO principles and Domain-Driven Design, although it isn't the primary objective of the book of course. This is especially true for the first and the last three chapters. If you've already read the nominal books DDD and you are familiar with Persistence Ignorance, then you can safely skim through these chapters unless you want to see the interpretation of the authors when it comes to these principles. If you are new to these concepts, then these chapters are of great value to wet your appetite.
 
Although this book covers a lot of ground, I would certainly recommend it when you're rather new to NHibernate and ORM's in general. I guess this still includes me, although I've been using NHibernate for quite some time now. If you already have some experience with NHibernate, then this book probably doesn't teach you that much. Still, it can quickly get you up to speed when you want to use a particular feature that you haven't used before. 
 
The only minor thing about this book is that I'm afraid that it will soon be out-of-date. The book only covers NHibernate 1.2.x and no features from the upcoming 2.0 release, which adds a lot of new and interesting features. It would be nice if the book already covered some of these features as most of them are ported from Hibernate itself, which is the original Java version.
 
On the other hand, this book provides an in-depth view of the basic features of NHibernate, which aren't necessarily going to change that much over time anyway.
 
Let me round off this post by saying that I'm really impressed by the list of books that Manning is going to release the next couple of months. These are the ones that I'm particularly interested in:
  
I already bought LINQ in Action and also read a lot of good things about C# in Depth, which I'm going to pick up soon.
 
Take care.
]]>
			http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/feed/
		7
		
		
		Integrating Castle Windsor and NHibernate with WCF
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/?utm_source=rss&utm_medium=rss&utm_campaign=integrating-castle-windsor-and-nhibernate-with-wcf
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/#comments
		Sun, 18 May 2008 14:08:20 +0000
		Jan Van Ryswyck
				
		

		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/
		
			Up until now, we were using the NHibernate facility of Castle Windsor for managing our NHibernate sessions in WCF. But, we want to have a session-per-request approach as one would use when integrating NHibernate with a regular web application. 
  
Yesterday I did a small spike to figure out how this should work. It turned out to be pretty easy. I used this excellent blog post written by Oran Dennison as my guide. 
  
First I created a class that implemented the IServiceBehavior interface.
  
   
public class DIServiceBehavior : IServiceBehavior
{
    private readonly ISessionFactory _sessionFactory;

    public DIServiceBehavior()
    {
        _sessionFactory = new Configuration()
            .Configure()
            .BuildSessionFactory();

        XmlConfigurator.Configure();    // Log4Net
    }

    public void ApplyDispatchBehavior(
             ServiceDescription serviceDescription, 
             ServiceHostBase serviceHostBase)
    {
        foreach(ChannelDispatcherBase cdb in 
                serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if(cd != null)
            {
                foreach(EndpointDispatcher ed in cd.Endpoints)
                {
                    ed.DispatchRuntime.InstanceProvider =
                        new DIInstanceProvider
                            (serviceDescription.ServiceType,
                              _sessionFactory);
                }
            }
        }
    }

    public void AddBindingParameters(
                ServiceDescription serviceDescription, 
                ServiceHostBase serviceHostBase,
                Collection<ServiceEndpoint> endpoints, 
                BindingParameterCollection bindingParameters) 
    { }
    
    public void Validate(ServiceDescription serviceDescription, 
                         ServiceHostBase serviceHostBase) 
    { }
}





The SessionFactory is created in the constructor because the ApplyDispatchBehaviour method can be called multiple times (for each endpoint). 



The next step is to create an instance provider by creating a class that implements the IInstanceProvider:




  
public class DIInstanceProvider : IInstanceProvider
{
    private const String NHibernateSessionKey = 
        "NHibernate.Session";

    private readonly Type _serviceType;
    private IDependencyContainer _dependencyContainer;
    private readonly ISessionFactory _sessionFactory;
    private ISession _session;

    public DIInstanceProvider(Type serviceType,
                               ISessionFactory sessionFactory)
    {
        Debug.Assert(null != serviceType, 
                     "null != serviceType");
        _serviceType = serviceType;

        Debug.Assert(null != sessionFactory, 
                     "null = sessionFactory");
        _sessionFactory = sessionFactory;
    }

    public Object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public Object GetInstance(InstanceContext instanceContext, 
                                Message message)
    {
        _dependencyContainer = new DependencyContainer();

        _session = _sessionFactory.OpenSession();
        _dependencyContainer
          .AddComponentInstance(NHibernateSessionKey, _session);

        return _dependencyContainer.Resolve(_serviceType);
    }

    public void ReleaseInstance(InstanceContext instanceContext, 
                                 Object instance)
    {
        if(null != _session)
        {
            _session.Close();
            _session = null;
        }

        if(null != _dependencyContainer)
        {
            _dependencyContainer.Dispose();
            _dependencyContainer = null;
        }
    }
}





I created a wrapper class around for Castle Windsor named DependencyContainer.  The GetInstance method opens a new session using the SessionFactory object we instantiated in the service behavior class. The session object is then registered with Castle Windsor. We can now implement our repositories like this:




  
public class SomeAggregateRepository
{
    private ISession _session;

    public SomeAggregateRepository(ISession session)
    {
        _session = session;
    }
    
    public SomeAggregate Get(Int64 id) 
    {
        return _session.Get<SomeAggregate>(id);
    }
}





When our service operation has been executed, the NHibernate is released by the ReleaseInstance method. Finishing our example, we need to implement a custom ServiceHost and a ServiceHostFactory:




  
public class DIServiceHost : ServiceHost
{
    public DependencyInjectionServiceHost() 
        : base() 
    { }
    
    public DIServiceHost(Type serviceType, 
                         params Uri[] baseAddresses) 
        : base(serviceType, baseAddresses) 
    { }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new DIServiceBehavior());
        base.OnOpening();
    }
}

public class DIServiceHostFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(
            Type serviceType, Uri[] baseAddresses)
    {
        return new DIServiceHost(serviceType, baseAddresses);
    }
}





The custom ServiceHostFactory class can now be used in the ServiceHost file required when doing IIS hosting:




  
<%@ ServiceHost Language="C#" 
                Debug="true" 
                Service="WindsorService.MyWindsorService" 
                Factory="WindsorService.DIServiceHostFactory"
                CodeBehind="MyWindsorService.svc.cs" %>





There is also another way for achieving this that I will be investigating the next week or so using the WCF Integration Facility for Castle Windsor. For some reason it is not available in the current release of the Castle stack so I have to grab it from the trunk. 



If you have any thoughts, improvements or suggestions I'm glad to hear them from you, my dear reader. It's the only way I'll ever learn :-). 



Till next time.
]]>
			http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/feed/
		9
		
		
		Implementing NHibernate Interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/?utm_source=rss&utm_medium=rss&utm_campaign=implementing-nhibernate-interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/#comments
		Thu, 15 May 2008 18:29:26 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/
		
			One of the areas where NHibernate really shines is it's high extensibility features. The NHibernate API provides a massive amount of interfaces that can be implemented for your own custom extension pleasure. 
  
For me this is a nice change as opposed to the many sealed API's put out by the Redmond collective (WCF being the exception, the Entity Framework confirming the rule).
  
Anyhow, with great power comes great responsibility. Today I encountered a rather difficult problem with NHibernate that could have been easily prevented by reading the documentation (note to self: use the CTRL-Q shortcut of Resharper more often).
  
We have implemented an interceptor for automatically configuring audit information as described by this great post from Ray Houston. 
  
   
public class AuditInformationInterceptor 
    : EmptyInterceptor
{
    Boolean OnSave(Object entity, Object id, Object[] state, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }

    Boolean OnFlushDirty(Object entity, Object id, 
        Object[] currentState, Object[] previousState, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }                  
}





The mistake we made is that we manipulated the audit information of the entity directly in the OnSave and OnFlushDirty methods. This only became apparent when saving an aggregate root with his child entities. Everything worked fine until we wanted to persist one of the child entities that should have been a piece of cake but turned out to be the messenger of trouble. NHibernate refused to perform an INSERT statement, but instead threw an UPDATE statement at us. 



After some debugging we found out that the audit information should have been manipulated through the state and currentState arguments of the OnSave and OnFlushDirty methods respectively.



The documentation of the OnSave method clearly states:



The interceptor may modify the state, which will be used for the SQL INSERT

    
and propagated to the persistent object



Lesson relearned. 



I'm off, reading some docs. Until next time.
]]>
			http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/feed/
		3
		
		
		On Persistence
		http://elegantcode.com/2008/05/01/on-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=on-persistence
		http://elegantcode.com/2008/05/01/on-persistence/#comments
		Thu, 01 May 2008 19:18:43 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/01/on-persistence/
		
			Earlier this week, I managed to convince our very wise decision makers to start using NHibernate for our persistence layer. My team mate on the project describes how it went. While I was reading Jeremy's train of thoughts, the following four lines made me realize we did the right thing:
  
Why are teams still writing persistence code by hand?  There's a bazillion persistence tools out there that all save development costs in some way over writing data access code by hand.  With very few exceptions, I'd say that at this point that if you're writing ADO.Net code or SQL by hand, you're stealing money from your employer.  
  
As another co-worker and NHibernate fan thoughtfully mentioned while congratulating us:
  
A small step for man, but a giant leap for mankind.
  
Few. What a week this turns out to be.
]]>
			http://elegantcode.com/2008/05/01/on-persistence/feed/
		2
		
		
		NHibernate 2.0 and Cascading Deletes
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-20-and-cascading-deletes-2
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/#comments
		Sat, 12 Apr 2008 18:58:12 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/
		
			The first alpha version of NHibernate 2.0 has been released some time ago. Oren has put a nice overview of the new features and the bugs that are solved for this first drop. In spite the fact that they put the word 'alpha' in the version name, it is actually RTM quality! 
  
One of the great new additions is the on-delete attribute of the key element for mapping collections:
  
<set name="Permissions" inverse="true" cascade="save-update">
  <key name="Authorization" on-delete="cascade"/>
  <one-to-many class="Permission"/>
</set>



This particular feature solves the issue I've had with one-shot deletes on inverse collections (which I described here). Configuring it this way ensures that NHibernate relies on database-level ON CASCADE DELETE foreign key constraints. This implies that when an object with a collection of child objects is deleted, a single DELETE  statement is used to remove all children at once instead of individual DELETE statements for each child object (which are called orphans at this point).



There are some things that you have to take into account here. First, this option bypasses NHibernate's optimistic locking strategy for versioned data. Second, make sure that you configure cascade="save-update" instead of cascade="all" to prevent NHibernate from performing delete cascade checks. This is important when lazy loading is enabled for the collection because it prevents that NHibernate loads one-to-many associations into memory. 



I'm really excited about this new release. Kudos to the men and women who have put so much effort in building such a wonderful ORM solution!



Till next time
]]>
			http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/feed/
		0
		
		
		A New NHibernate Blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/?utm_source=rss&utm_medium=rss&utm_campaign=a-new-nhibernate-blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/#comments
		Tue, 01 Apr 2008 15:26:32 +0000
		Alex Mueller
				
		
		
		

		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/
		
			Craig Neuwirt recently started a blog focused on NHibernate, as mentioned by Ayende. NHibernate is an ORM tool I have used on current and past projects and it is something I feel I would like I want to study further. So far, Craig is walking us through NHibernate from the ground-up, with the latest and greatest. I anticipate this being an informative blog to follow.

The NHibernate FAQ
Craig Neuwirt
Hibernating Rhinos]]>
			http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/feed/
		2
		
		
		NHibernate IQuery to ISQLQuery Black Magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-iquery-to-isqlquery-black-magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/#comments
		Fri, 16 Nov 2007 06:12:55 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/
		
			posted on the forums and learned that: I'd run into a known bug / limitation.

Therefore I resorted to using ISQLQuery (yuk). I fixed several repository methods and then I ran into a very complicated IQuery. It was very painful to write the first time. In fact it was this experience that had caused me to change to using ICriteria as my default query method with specifications. I had a full suite of unit tests to protect me so I was confident that I could make the changes without breaking anything but I didn't want to do the conversion manually. Surely there was a trick?

It turns out that there is - NHibernate.Hql.Classic.QueryTranslator. The property that I needed is protected but thanks to a quick search of the forums I didn't even need to write my own reflection based method of calling it because someone had done it for me (thanks Nels). So what I did was take the HQL and convert it to SQL. I then did some string replacement to morph the SQL into what I needed. I am not proud of this but it was fast and it goes to show for flexible NHibernate is if you want to do some certifiable things.]]>
			http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/feed/
		0
		
		
		DTOs / Presentation Model and ICriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/?utm_source=rss&utm_medium=rss&utm_campaign=dtos-presentation-model-and-icriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/#comments
		Tue, 06 Nov 2007 06:11:41 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/
		
			NHibernate Projections I used HQL (IQuery) in the repository to define the query.

There are a some things that I don't like about HQL. For example the query is defined as a string. Strings are problematic because errors can't be detected at compile time. ICriteria queries go some way to alleviating this although they are certainly not perfect in this regard. You are writing tests against your repositories though aren't you?

But the reliance on strings is not the only problem with HQL. Today I needed to create a search screen. I wanted to use a variation of the technique that Ayende demonstrates here. With HQL the repository methods become ugly very quickly (and I mean wake up sweating at 2 am ugly). There is a mass of conditional string concatenation. And for each parameter I need to change 2 pieces of code (the code that builds the HQL and the code that binds the parameters).

So I decided to figure out how to use ICriteria to return a DTO. It transpires that the following code produces the same result as the HQL that I used before:

 



public List<InspectorDropDownDTO> GetAll()


{


 ICriteria q = session.CreateCriteria(typeof(Inspector), "i");


 q.CreateAlias("Person", "p");


 q.SetProjection(Projections.ProjectionList()


 .Add(Projections.Property("i.ID"), "InspectorID")


 .Add(Projections.Property("p.FirstName"), "FirstName")


 .Add(Projections.Property("p.LastName"), "LastName"));


 q.SetResultTransformer(Transformers.AliasToBean(typeof(InspectorDropDownDTO)));


 return q.List<InspectorDropDownDTO>();


}

It should be noted that the DTO itself is different with this method. A default constructor is now all that's needed because the AliasToBean transformer seems to work properly with ICriteria.

 



public class InspectorDropDownDTO


{


 private long _inspectorID;


 private string _firstName;


 private string _lastName;




 public long InspectorID { get { return _inspectorID; } set { _inspectorID = value; } }


 public string FirstName { get { return _firstName; } set { _firstName = value; } }


 public string LastName { get { return _lastName; } set { _lastName = value; } }


 public string FullName { get { return FirstName + " " + LastName; } }


}

Also note that you no longer need to import the DTO in an hbm.xml file.]]>
			http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/feed/
		2
		
		
		DTOs Simplify Complex Screens
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/?utm_source=rss&utm_medium=rss&utm_campaign=book-review-nhibernate-in-action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/#comments
		Sat, 14 Jun 2008 20:42:15 +0000
		Jan Van Ryswyck
				
		
		

		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/
		
			kuate_cover150 Writing this book review feels kind of weird  because it hasn't actually hit the shelves yet. It is accessible however through the Manning Early Access Program. This book provides a clear insight of using NHibernate as the data access layer of your applications and beyond. 
 
The excessive amount of NHibernate features  isn't the only thing that is written down. There is also a good coverage of OO principles and Domain-Driven Design, although it isn't the primary objective of the book of course. This is especially true for the first and the last three chapters. If you've already read the nominal books DDD and you are familiar with Persistence Ignorance, then you can safely skim through these chapters unless you want to see the interpretation of the authors when it comes to these principles. If you are new to these concepts, then these chapters are of great value to wet your appetite.
 
Although this book covers a lot of ground, I would certainly recommend it when you're rather new to NHibernate and ORM's in general. I guess this still includes me, although I've been using NHibernate for quite some time now. If you already have some experience with NHibernate, then this book probably doesn't teach you that much. Still, it can quickly get you up to speed when you want to use a particular feature that you haven't used before. 
 
The only minor thing about this book is that I'm afraid that it will soon be out-of-date. The book only covers NHibernate 1.2.x and no features from the upcoming 2.0 release, which adds a lot of new and interesting features. It would be nice if the book already covered some of these features as most of them are ported from Hibernate itself, which is the original Java version.
 
On the other hand, this book provides an in-depth view of the basic features of NHibernate, which aren't necessarily going to change that much over time anyway.
 
Let me round off this post by saying that I'm really impressed by the list of books that Manning is going to release the next couple of months. These are the ones that I'm particularly interested in:
  
I already bought LINQ in Action and also read a lot of good things about C# in Depth, which I'm going to pick up soon.
 
Take care.
]]>
			http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/feed/
		7
		
		
		Elegant Code » NHibernate
	
	http://elegantcode.com
	
	Tue, 15 May 2012 10:00:00 +0000
	en
	hourly
	1
	http://wordpress.org/?v=3.3.1
		
		FubuMVC From Scratch – Part 4 Persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments
		Wed, 25 Mar 2009 21:22:00 +0000
		Ryan Kelley
				
		
		
		
		
		
		

		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/
		
			Previous posts in series:    
Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project
  
We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.
  
Class and Interfaces we have to implement: 
  
       
  • ISessionSourceConfiguration 
    •     
  • SQLServerSessionSourceConfiguration 
    •     
  • IUnitOfWork 
    •     
  • INHibernateUnitOfWork 
    •     
  • NHibernateUnitOfWork 
    •     
  • IRepository 
    •     
  • NHibernateRepository 
    •     
  • DomainEntity 
    •     
  • IDomainQuery 
    •     
  • FubuSamplePersistenceModel 
    •  
  
Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence
  
Before we start you probably want to go ahead and add the following references to your core project and Web project
  
FubuMVC-Persist-Ref 
  
Let’s just work our way down the list and get these files implemented. 
  
ISessionSourceConfiguration
  
   
     
public interface ISessionSourceConfiguration


    
{


    
    bool IsNewDatabase { get; }


    
    ISessionSource CreateSessionSource(PersistenceModel model);


    
}

  





SQLServerSessionSourceConfiguration




  

    
public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration


    
{


    
    #region Implementation of ISessionSourceConfiguration


    
 


    
    public bool IsNewDatabase


    
    {


    
        get { return false; }


    
    }


    
 


    
    public ISessionSource CreateSessionSource(PersistenceModel model)


    
    {


    
        var properties = GetProperties();


    
        var source = new SessionSource(properties, model);


    
 


    
        create_schema_if_it_does_not_already_exist(source);


    
 


    
        return source;


    
    }


    
 


    
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)


    
    {


    
        if (IsNewDatabase) source.BuildSchema();


    
    }


    
 


    
    protected IDictionary<string, string> GetProperties()


    
    {


    
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;


    
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);


    
        config.ShowSql();


    
        config.UseOuterJoin();


    
 


    
        return config.ToProperties();


    
    }


    
    #endregion


    
}

  





A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.



IUnitOfWork




  

    
public interface IUnitOfWork : IDisposable


    
{


    
    void Initialize();


    
    void Commit();


    
    void Rollback();


    
}

  





INHibernateUnitOfWork




  

    
public interface INHibernateUnitOfWork : IUnitOfWork


    
{


    
    ISession CurrentSession { get; }


    
}

  





NHibernateUnitOfWork




  

    
public class NHibernateUnitOfWork : INHibernateUnitOfWork


    
{


    
    private ITransaction _transaction;


    
    private bool _isDisposed;


    
    private readonly ISessionSource _source;


    
    private bool _isInitialized;


    
 


    
    public NHibernateUnitOfWork(ISessionSource source)


    
    {


    
        _source = source;


    
    }


    
 


    
    public void Initialize()


    
    {


    
        should_not_currently_be_disposed();


    
 


    
        CurrentSession = _source.CreateSession();


    
        begin_new_transaction();


    
 


    
        _isInitialized = true;


    
    }


    
 


    
    public ISession CurrentSession { get; private set; }


    
 


    
    public void Commit()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Commit();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void begin_new_transaction()


    
    {


    
        if (_transaction != null)


    
        {


    
            _transaction.Dispose();


    
        }


    
 


    
        _transaction = CurrentSession.BeginTransaction();


    
    }


    
 


    
    public void Rollback()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Rollback();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void should_not_currently_be_disposed()


    
    {


    
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);


    
    }


    
 


    
    private void should_be_initialized_first()


    
    {


    
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");


    
    }


    
 


    
    public void Dispose()


    
    {


    
        if (_isDisposed || !_isInitialized) return;


    
 


    
        _transaction.Dispose();


    
        CurrentSession.Dispose();


    
 


    
        _isDisposed = true;


    
    }


    
}

  





IRepository




  

    
public interface IRepository


    
{


    
    void Save<ENTITY>(ENTITY entity)


    
        where ENTITY : DomainEntity;


    
 


    
    ENTITY Load<ENTITY>(Guid id)


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>()


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)


    
        where ENTITY : DomainEntity;


    
 


    
    void Delete<ENTITY>(ENTITY entity);


    
 


    
    void DeleteAll<ENTITY>();


    
}

  





NHibernateRepository




  

    
public class NHibernateRepository : IRepository


    
{


    
    private readonly INHibernateUnitOfWork _unitOfWork;


    
 


    
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity


    
    {


    
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);


    
    }


    
 


    
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>();


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);


    
    }


    
 


    
    public void Delete<ENTITY>(ENTITY entity)


    
    {


    
        _unitOfWork.CurrentSession.Delete(entity);   


    
    }


    
 


    
    public void DeleteAll<ENTITY>()


    
    {


    
        var query = String.Format("from {0}", typeof(ENTITY).Name);


    
        _unitOfWork.CurrentSession.Delete(query);   


    
    }


    
}

  





DomainEntity



Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository




  

    
public class DomainEntity : IEquatable<DomainEntity>


    
{


    
    public virtual Guid ID { get; set; }


    
 


    
    public virtual bool Equals(DomainEntity other)


    
    {


    
        if (ReferenceEquals(null, other)) return false;


    
        if (ReferenceEquals(this, other)) return true;


    
        return other.ID.Equals(ID);


    
    }


    
 


    
    public override bool Equals(object obj)


    
    {


    
        if (ReferenceEquals(null, obj)) return false;


    
        if (ReferenceEquals(this, obj)) return true;


    
        if (obj.GetType() != GetType()) return false;


    
        return Equals((DomainEntity)obj);


    
    }


    
 


    
    public override int GetHashCode()


    
    {


    
        return ID.GetHashCode();


    
    }


    
 


    
    public static bool operator ==(DomainEntity left, DomainEntity right)


    
    {


    
        return Equals(left, right);


    
    }


    
 


    
    public static bool operator !=(DomainEntity left, DomainEntity right)


    
    {


    
        return !Equals(left, right);


    
    }


    
}

  





IDomainQuery




  

    
public interface IDomainQuery<ENTITY>


    
    where ENTITY : DomainEntity


    
{


    
    Expression<Func<ENTITY, bool>> Expression { get; }


    
}

  





FubuSamplePersistenceModel




  

    
namespace FubuSample.Core.Domain.Persistence


    
{


    
    public class FubuSamplePersistenceModel : PersistenceModel


    
    {


    
        public FubuSamplePersistenceModel()


    
        {


    
            addMappingsFromThisAssembly();


    
        }


    
    }


    
}

  





Now that we have all the puzzle pieces in place we need to hook them up and make them do some work. Open up FubuSampleWebRegistry 



And add the following code:




  

    
protected override void configure()


    
{


    
    ForRequestedType<ISessionSourceConfiguration>().AsSingletons()


    
        .TheDefault.Is.OfConcreteType<SQLServerSessionSourceConfiguration>();


    
 


    
 


    
    ForRequestedType<ISessionSource>().AsSingletons()


    
        .TheDefault.Is.ConstructedBy(ctx =>


    
                                     ctx.GetInstance<ISessionSourceConfiguration>()


    
                                         .CreateSessionSource(new FubuSamplePersistenceModel()));


    
 


    
    ForRequestedType<IUnitOfWork>().TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<INHibernateUnitOfWork>());


    
 


    
    ForRequestedType<INHibernateUnitOfWork>().CacheBy(InstanceScope.Hybrid)


    
        .TheDefault.Is.OfConcreteType<NHibernateUnitOfWork>();


    
 


    
    ForRequestedType<IRepository>().TheDefault.Is.OfConcreteType<NHibernateRepository>();


    
}

  





With a little luck and all of our mad skills, we should be able to talk to the database now. So we need to plumb our simple product object up to talk to NHibernate. We will do this with a mapping file, and since we are using FluentNHibernate we can do this strongly typed.



Make the following modifications to Product: Extend DomainEntity and get rid of Id Property, it is inherited




  

    
public class Product : DomainEntity


    
{


    
    public virtual string Name { get; set; }


    
    public virtual string Description { get; set; }


    
}

  





Add mapping file for Product:




  

    
namespace FubuSample.Core.Domain.Mapping


    
{


    
    public class ProductMap : ClassMap<Product>


    
    {


    
        public ProductMap()


    
        {


    
            Id(e => e.ID).GeneratedBy.GuidComb();


    
 


    
            Map(p => p.Name);


    
            Map(p => p.Description);


    
            


    
        }


    
    }


    
}

  





You may also want to setup your connection string at this point in the Web.Config file, mine looks like this:




  

    
<add name="MYDBKEY" connectionString="Data Source=LOCALHOST;initial catalog=FubuSample;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />

  





I also created an empty database in my local SQL Server instance called “FubuSample” And then I went back to SQLServerSessionSourceConfiguration and changed the value of IsNewDatabase to return true. This will create the schema for the database when the application first runs. There is a multitude of different ways that we can handle this, but this was easy for the tutorial purposes.



Next we will add a behavior to our core project and tell FubuMVC to apply that behavior to all or our ControllerActions.



Create a class named “access_the_database_through_a_unit_of_work” in your Core.Web.Behaviors namespace. The contents will look like this:




  

    
public class access_the_database_through_a_unit_of_work : IControllerActionBehavior


    
{


    
    private readonly IUnitOfWork _unitOfWork;


    
 


    
    public access_the_database_through_a_unit_of_work(IUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public IControllerActionBehavior InsideBehavior { get; set; }


    
    public IInvocationResult Result { get; set; }


    
 


    
    public OUTPUT Invoke<INPUT, OUTPUT>(INPUT input, Func<INPUT, OUTPUT> func)


    
        where INPUT : class


    
        where OUTPUT : class


    
    {


    
        _unitOfWork.Initialize();


    
 


    
        try


    
        {


    
            var output = InsideBehavior.Invoke(input, func);


    
            Result = InsideBehavior.Result;


    
 


    
            _unitOfWork.Commit();


    
 


    
            return output;


    
        }


    
        catch


    
        {


    
            _unitOfWork.Rollback();


    
            throw;


    
        }


    
        finally


    
        {


    
            _unitOfWork.Dispose();


    
        }


    
    }


    
}

  





Now to tell FubuMVC what to do, open up Global.asax.cs or your Bootstrapper, wherever you are doing the configuration of FubuMVC. In this project we are doing it in Global.asax.cs Add a new behavior to the section that starts with “x.ByDefault.EveryControllerAction” so it looks like this:




  

    
x.ByDefault.EveryControllerAction(d =>


    
   {


    
       d.Will<execute_the_result>();


    
       d.Will<access_the_database_through_a_unit_of_work>();


    
   });

  





The last thing we will do is open up HomeController and add this code above the Index action:




  

    
private IRepository _repository;


    
 


    
public HomeController(IRepository repository)


    
{


    
    _repository = repository;


    
}

  





I also modified the Index action to go ahead and create some database values before we query for them just so we can test this thing. (I only did this for the tutorial, I swear) So modify the Index action to look like this:




  

    
public IndexViewModel Index(IndexSetupViewModel inModel)


    
{


    
    var prod1 = new Product {Name = "TestProduct1", Description = "This is a test product"};


    
 


    
    _repository.Save(prod1);


    
 


    
    var prod2 = new Product {Name = "TestProduct2", Description = "This is a test product"};


    
 


    
    _repository.Save(prod2);


    
 


    
    var outModel = new IndexViewModel();


    
 


    
    var productList = _repository.Query<Product>();


    
 


    
    outModel.Products = productList.ToList().Select(x => new ProductDisplay(x));


    
 


    
    return outModel;


    
}

  





Now with you should be able to run your web app and browse to /home and all this will be executed and you will be on your way to creating a whole bunch of persist able objects for use with your FubuMVC app.



As always, feedback is welcome.
]]>
			http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/feed/
		9
		
		
		Book review: NHibernate in Action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/?utm_source=rss&utm_medium=rss&utm_campaign=book-review-nhibernate-in-action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/#comments
		Sat, 14 Jun 2008 20:42:15 +0000
		Jan Van Ryswyck
				
		
		

		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/
		
			kuate_cover150 Writing this book review feels kind of weird  because it hasn't actually hit the shelves yet. It is accessible however through the Manning Early Access Program. This book provides a clear insight of using NHibernate as the data access layer of your applications and beyond. 
 
The excessive amount of NHibernate features  isn't the only thing that is written down. There is also a good coverage of OO principles and Domain-Driven Design, although it isn't the primary objective of the book of course. This is especially true for the first and the last three chapters. If you've already read the nominal books DDD and you are familiar with Persistence Ignorance, then you can safely skim through these chapters unless you want to see the interpretation of the authors when it comes to these principles. If you are new to these concepts, then these chapters are of great value to wet your appetite.
 
Although this book covers a lot of ground, I would certainly recommend it when you're rather new to NHibernate and ORM's in general. I guess this still includes me, although I've been using NHibernate for quite some time now. If you already have some experience with NHibernate, then this book probably doesn't teach you that much. Still, it can quickly get you up to speed when you want to use a particular feature that you haven't used before. 
 
The only minor thing about this book is that I'm afraid that it will soon be out-of-date. The book only covers NHibernate 1.2.x and no features from the upcoming 2.0 release, which adds a lot of new and interesting features. It would be nice if the book already covered some of these features as most of them are ported from Hibernate itself, which is the original Java version.
 
On the other hand, this book provides an in-depth view of the basic features of NHibernate, which aren't necessarily going to change that much over time anyway.
 
Let me round off this post by saying that I'm really impressed by the list of books that Manning is going to release the next couple of months. These are the ones that I'm particularly interested in:
  
I already bought LINQ in Action and also read a lot of good things about C# in Depth, which I'm going to pick up soon.
 
Take care.
]]>
			http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/feed/
		7
		
		
		Integrating Castle Windsor and NHibernate with WCF
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/?utm_source=rss&utm_medium=rss&utm_campaign=integrating-castle-windsor-and-nhibernate-with-wcf
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/#comments
		Sun, 18 May 2008 14:08:20 +0000
		Jan Van Ryswyck
				
		

		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/
		
			Up until now, we were using the NHibernate facility of Castle Windsor for managing our NHibernate sessions in WCF. But, we want to have a session-per-request approach as one would use when integrating NHibernate with a regular web application. 
  
Yesterday I did a small spike to figure out how this should work. It turned out to be pretty easy. I used this excellent blog post written by Oran Dennison as my guide. 
  
First I created a class that implemented the IServiceBehavior interface.
  
   
public class DIServiceBehavior : IServiceBehavior
{
    private readonly ISessionFactory _sessionFactory;

    public DIServiceBehavior()
    {
        _sessionFactory = new Configuration()
            .Configure()
            .BuildSessionFactory();

        XmlConfigurator.Configure();    // Log4Net
    }

    public void ApplyDispatchBehavior(
             ServiceDescription serviceDescription, 
             ServiceHostBase serviceHostBase)
    {
        foreach(ChannelDispatcherBase cdb in 
                serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if(cd != null)
            {
                foreach(EndpointDispatcher ed in cd.Endpoints)
                {
                    ed.DispatchRuntime.InstanceProvider =
                        new DIInstanceProvider
                            (serviceDescription.ServiceType,
                              _sessionFactory);
                }
            }
        }
    }

    public void AddBindingParameters(
                ServiceDescription serviceDescription, 
                ServiceHostBase serviceHostBase,
                Collection<ServiceEndpoint> endpoints, 
                BindingParameterCollection bindingParameters) 
    { }
    
    public void Validate(ServiceDescription serviceDescription, 
                         ServiceHostBase serviceHostBase) 
    { }
}





The SessionFactory is created in the constructor because the ApplyDispatchBehaviour method can be called multiple times (for each endpoint). 



The next step is to create an instance provider by creating a class that implements the IInstanceProvider:




  
public class DIInstanceProvider : IInstanceProvider
{
    private const String NHibernateSessionKey = 
        "NHibernate.Session";

    private readonly Type _serviceType;
    private IDependencyContainer _dependencyContainer;
    private readonly ISessionFactory _sessionFactory;
    private ISession _session;

    public DIInstanceProvider(Type serviceType,
                               ISessionFactory sessionFactory)
    {
        Debug.Assert(null != serviceType, 
                     "null != serviceType");
        _serviceType = serviceType;

        Debug.Assert(null != sessionFactory, 
                     "null = sessionFactory");
        _sessionFactory = sessionFactory;
    }

    public Object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public Object GetInstance(InstanceContext instanceContext, 
                                Message message)
    {
        _dependencyContainer = new DependencyContainer();

        _session = _sessionFactory.OpenSession();
        _dependencyContainer
          .AddComponentInstance(NHibernateSessionKey, _session);

        return _dependencyContainer.Resolve(_serviceType);
    }

    public void ReleaseInstance(InstanceContext instanceContext, 
                                 Object instance)
    {
        if(null != _session)
        {
            _session.Close();
            _session = null;
        }

        if(null != _dependencyContainer)
        {
            _dependencyContainer.Dispose();
            _dependencyContainer = null;
        }
    }
}





I created a wrapper class around for Castle Windsor named DependencyContainer.  The GetInstance method opens a new session using the SessionFactory object we instantiated in the service behavior class. The session object is then registered with Castle Windsor. We can now implement our repositories like this:




  
public class SomeAggregateRepository
{
    private ISession _session;

    public SomeAggregateRepository(ISession session)
    {
        _session = session;
    }
    
    public SomeAggregate Get(Int64 id) 
    {
        return _session.Get<SomeAggregate>(id);
    }
}





When our service operation has been executed, the NHibernate is released by the ReleaseInstance method. Finishing our example, we need to implement a custom ServiceHost and a ServiceHostFactory:




  
public class DIServiceHost : ServiceHost
{
    public DependencyInjectionServiceHost() 
        : base() 
    { }
    
    public DIServiceHost(Type serviceType, 
                         params Uri[] baseAddresses) 
        : base(serviceType, baseAddresses) 
    { }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new DIServiceBehavior());
        base.OnOpening();
    }
}

public class DIServiceHostFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(
            Type serviceType, Uri[] baseAddresses)
    {
        return new DIServiceHost(serviceType, baseAddresses);
    }
}





The custom ServiceHostFactory class can now be used in the ServiceHost file required when doing IIS hosting:




  
<%@ ServiceHost Language="C#" 
                Debug="true" 
                Service="WindsorService.MyWindsorService" 
                Factory="WindsorService.DIServiceHostFactory"
                CodeBehind="MyWindsorService.svc.cs" %>





There is also another way for achieving this that I will be investigating the next week or so using the WCF Integration Facility for Castle Windsor. For some reason it is not available in the current release of the Castle stack so I have to grab it from the trunk. 



If you have any thoughts, improvements or suggestions I'm glad to hear them from you, my dear reader. It's the only way I'll ever learn :-). 



Till next time.
]]>
			http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/feed/
		9
		
		
		Implementing NHibernate Interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/?utm_source=rss&utm_medium=rss&utm_campaign=implementing-nhibernate-interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/#comments
		Thu, 15 May 2008 18:29:26 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/
		
			One of the areas where NHibernate really shines is it's high extensibility features. The NHibernate API provides a massive amount of interfaces that can be implemented for your own custom extension pleasure. 
  
For me this is a nice change as opposed to the many sealed API's put out by the Redmond collective (WCF being the exception, the Entity Framework confirming the rule).
  
Anyhow, with great power comes great responsibility. Today I encountered a rather difficult problem with NHibernate that could have been easily prevented by reading the documentation (note to self: use the CTRL-Q shortcut of Resharper more often).
  
We have implemented an interceptor for automatically configuring audit information as described by this great post from Ray Houston. 
  
   
public class AuditInformationInterceptor 
    : EmptyInterceptor
{
    Boolean OnSave(Object entity, Object id, Object[] state, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }

    Boolean OnFlushDirty(Object entity, Object id, 
        Object[] currentState, Object[] previousState, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }                  
}





The mistake we made is that we manipulated the audit information of the entity directly in the OnSave and OnFlushDirty methods. This only became apparent when saving an aggregate root with his child entities. Everything worked fine until we wanted to persist one of the child entities that should have been a piece of cake but turned out to be the messenger of trouble. NHibernate refused to perform an INSERT statement, but instead threw an UPDATE statement at us. 



After some debugging we found out that the audit information should have been manipulated through the state and currentState arguments of the OnSave and OnFlushDirty methods respectively.



The documentation of the OnSave method clearly states:



The interceptor may modify the state, which will be used for the SQL INSERT

    
and propagated to the persistent object



Lesson relearned. 



I'm off, reading some docs. Until next time.
]]>
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		3
		
		
		On Persistence
		http://elegantcode.com/2008/05/01/on-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=on-persistence
		http://elegantcode.com/2008/05/01/on-persistence/#comments
		Thu, 01 May 2008 19:18:43 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/01/on-persistence/
		
			Earlier this week, I managed to convince our very wise decision makers to start using NHibernate for our persistence layer. My team mate on the project describes how it went. While I was reading Jeremy's train of thoughts, the following four lines made me realize we did the right thing:
  
Why are teams still writing persistence code by hand?  There's a bazillion persistence tools out there that all save development costs in some way over writing data access code by hand.  With very few exceptions, I'd say that at this point that if you're writing ADO.Net code or SQL by hand, you're stealing money from your employer.  
  
As another co-worker and NHibernate fan thoughtfully mentioned while congratulating us:
  
A small step for man, but a giant leap for mankind.
  
Few. What a week this turns out to be.
]]>
			http://elegantcode.com/2008/05/01/on-persistence/feed/
		2
		
		
		NHibernate 2.0 and Cascading Deletes
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-20-and-cascading-deletes-2
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/#comments
		Sat, 12 Apr 2008 18:58:12 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/
		
			The first alpha version of NHibernate 2.0 has been released some time ago. Oren has put a nice overview of the new features and the bugs that are solved for this first drop. In spite the fact that they put the word 'alpha' in the version name, it is actually RTM quality! 
  
One of the great new additions is the on-delete attribute of the key element for mapping collections:
  
<set name="Permissions" inverse="true" cascade="save-update">
  <key name="Authorization" on-delete="cascade"/>
  <one-to-many class="Permission"/>
</set>



This particular feature solves the issue I've had with one-shot deletes on inverse collections (which I described here). Configuring it this way ensures that NHibernate relies on database-level ON CASCADE DELETE foreign key constraints. This implies that when an object with a collection of child objects is deleted, a single DELETE  statement is used to remove all children at once instead of individual DELETE statements for each child object (which are called orphans at this point).



There are some things that you have to take into account here. First, this option bypasses NHibernate's optimistic locking strategy for versioned data. Second, make sure that you configure cascade="save-update" instead of cascade="all" to prevent NHibernate from performing delete cascade checks. This is important when lazy loading is enabled for the collection because it prevents that NHibernate loads one-to-many associations into memory. 



I'm really excited about this new release. Kudos to the men and women who have put so much effort in building such a wonderful ORM solution!



Till next time
]]>
			http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/feed/
		0
		
		
		A New NHibernate Blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/?utm_source=rss&utm_medium=rss&utm_campaign=a-new-nhibernate-blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/#comments
		Tue, 01 Apr 2008 15:26:32 +0000
		Alex Mueller
				
		
		
		

		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/
		
			Craig Neuwirt recently started a blog focused on NHibernate, as mentioned by Ayende. NHibernate is an ORM tool I have used on current and past projects and it is something I feel I would like I want to study further. So far, Craig is walking us through NHibernate from the ground-up, with the latest and greatest. I anticipate this being an informative blog to follow.

The NHibernate FAQ
Craig Neuwirt
Hibernating Rhinos]]>
			http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/feed/
		2
		
		
		NHibernate IQuery to ISQLQuery Black Magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-iquery-to-isqlquery-black-magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/#comments
		Fri, 16 Nov 2007 06:12:55 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/
		
			posted on the forums and learned that: I'd run into a known bug / limitation.

Therefore I resorted to using ISQLQuery (yuk). I fixed several repository methods and then I ran into a very complicated IQuery. It was very painful to write the first time. In fact it was this experience that had caused me to change to using ICriteria as my default query method with specifications. I had a full suite of unit tests to protect me so I was confident that I could make the changes without breaking anything but I didn't want to do the conversion manually. Surely there was a trick?

It turns out that there is - NHibernate.Hql.Classic.QueryTranslator. The property that I needed is protected but thanks to a quick search of the forums I didn't even need to write my own reflection based method of calling it because someone had done it for me (thanks Nels). So what I did was take the HQL and convert it to SQL. I then did some string replacement to morph the SQL into what I needed. I am not proud of this but it was fast and it goes to show for flexible NHibernate is if you want to do some certifiable things.]]>
			http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/feed/
		0
		
		
		DTOs / Presentation Model and ICriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/?utm_source=rss&utm_medium=rss&utm_campaign=dtos-presentation-model-and-icriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/#comments
		Tue, 06 Nov 2007 06:11:41 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/
		
			NHibernate Projections I used HQL (IQuery) in the repository to define the query.

There are a some things that I don't like about HQL. For example the query is defined as a string. Strings are problematic because errors can't be detected at compile time. ICriteria queries go some way to alleviating this although they are certainly not perfect in this regard. You are writing tests against your repositories though aren't you?

But the reliance on strings is not the only problem with HQL. Today I needed to create a search screen. I wanted to use a variation of the technique that Ayende demonstrates here. With HQL the repository methods become ugly very quickly (and I mean wake up sweating at 2 am ugly). There is a mass of conditional string concatenation. And for each parameter I need to change 2 pieces of code (the code that builds the HQL and the code that binds the parameters).

So I decided to figure out how to use ICriteria to return a DTO. It transpires that the following code produces the same result as the HQL that I used before:

 



public List<InspectorDropDownDTO> GetAll()


{


 ICriteria q = session.CreateCriteria(typeof(Inspector), "i");


 q.CreateAlias("Person", "p");


 q.SetProjection(Projections.ProjectionList()


 .Add(Projections.Property("i.ID"), "InspectorID")


 .Add(Projections.Property("p.FirstName"), "FirstName")


 .Add(Projections.Property("p.LastName"), "LastName"));


 q.SetResultTransformer(Transformers.AliasToBean(typeof(InspectorDropDownDTO)));


 return q.List<InspectorDropDownDTO>();


}

It should be noted that the DTO itself is different with this method. A default constructor is now all that's needed because the AliasToBean transformer seems to work properly with ICriteria.

 



public class InspectorDropDownDTO


{


 private long _inspectorID;


 private string _firstName;


 private string _lastName;




 public long InspectorID { get { return _inspectorID; } set { _inspectorID = value; } }


 public string FirstName { get { return _firstName; } set { _firstName = value; } }


 public string LastName { get { return _lastName; } set { _lastName = value; } }


 public string FullName { get { return FirstName + " " + LastName; } }


}

Also note that you no longer need to import the DTO in an hbm.xml file.]]>
			http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/feed/
		2
		
		
		DTOs Simplify Complex Screens
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/?utm_source=rss&utm_medium=rss&utm_campaign=integrating-castle-windsor-and-nhibernate-with-wcf
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/#comments
		Sun, 18 May 2008 14:08:20 +0000
		Jan Van Ryswyck
				
		

		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/
		
			Up until now, we were using the NHibernate facility of Castle Windsor for managing our NHibernate sessions in WCF. But, we want to have a session-per-request approach as one would use when integrating NHibernate with a regular web application. 
  
Yesterday I did a small spike to figure out how this should work. It turned out to be pretty easy. I used this excellent blog post written by Oran Dennison as my guide. 
  
First I created a class that implemented the IServiceBehavior interface.
  
   
public class DIServiceBehavior : IServiceBehavior
{
    private readonly ISessionFactory _sessionFactory;

    public DIServiceBehavior()
    {
        _sessionFactory = new Configuration()
            .Configure()
            .BuildSessionFactory();

        XmlConfigurator.Configure();    // Log4Net
    }

    public void ApplyDispatchBehavior(
             ServiceDescription serviceDescription, 
             ServiceHostBase serviceHostBase)
    {
        foreach(ChannelDispatcherBase cdb in 
                serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if(cd != null)
            {
                foreach(EndpointDispatcher ed in cd.Endpoints)
                {
                    ed.DispatchRuntime.InstanceProvider =
                        new DIInstanceProvider
                            (serviceDescription.ServiceType,
                              _sessionFactory);
                }
            }
        }
    }

    public void AddBindingParameters(
                ServiceDescription serviceDescription, 
                ServiceHostBase serviceHostBase,
                Collection<ServiceEndpoint> endpoints, 
                BindingParameterCollection bindingParameters) 
    { }
    
    public void Validate(ServiceDescription serviceDescription, 
                         ServiceHostBase serviceHostBase) 
    { }
}





The SessionFactory is created in the constructor because the ApplyDispatchBehaviour method can be called multiple times (for each endpoint). 



The next step is to create an instance provider by creating a class that implements the IInstanceProvider:




  
public class DIInstanceProvider : IInstanceProvider
{
    private const String NHibernateSessionKey = 
        "NHibernate.Session";

    private readonly Type _serviceType;
    private IDependencyContainer _dependencyContainer;
    private readonly ISessionFactory _sessionFactory;
    private ISession _session;

    public DIInstanceProvider(Type serviceType,
                               ISessionFactory sessionFactory)
    {
        Debug.Assert(null != serviceType, 
                     "null != serviceType");
        _serviceType = serviceType;

        Debug.Assert(null != sessionFactory, 
                     "null = sessionFactory");
        _sessionFactory = sessionFactory;
    }

    public Object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public Object GetInstance(InstanceContext instanceContext, 
                                Message message)
    {
        _dependencyContainer = new DependencyContainer();

        _session = _sessionFactory.OpenSession();
        _dependencyContainer
          .AddComponentInstance(NHibernateSessionKey, _session);

        return _dependencyContainer.Resolve(_serviceType);
    }

    public void ReleaseInstance(InstanceContext instanceContext, 
                                 Object instance)
    {
        if(null != _session)
        {
            _session.Close();
            _session = null;
        }

        if(null != _dependencyContainer)
        {
            _dependencyContainer.Dispose();
            _dependencyContainer = null;
        }
    }
}





I created a wrapper class around for Castle Windsor named DependencyContainer.  The GetInstance method opens a new session using the SessionFactory object we instantiated in the service behavior class. The session object is then registered with Castle Windsor. We can now implement our repositories like this:




  
public class SomeAggregateRepository
{
    private ISession _session;

    public SomeAggregateRepository(ISession session)
    {
        _session = session;
    }
    
    public SomeAggregate Get(Int64 id) 
    {
        return _session.Get<SomeAggregate>(id);
    }
}





When our service operation has been executed, the NHibernate is released by the ReleaseInstance method. Finishing our example, we need to implement a custom ServiceHost and a ServiceHostFactory:




  
public class DIServiceHost : ServiceHost
{
    public DependencyInjectionServiceHost() 
        : base() 
    { }
    
    public DIServiceHost(Type serviceType, 
                         params Uri[] baseAddresses) 
        : base(serviceType, baseAddresses) 
    { }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new DIServiceBehavior());
        base.OnOpening();
    }
}

public class DIServiceHostFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(
            Type serviceType, Uri[] baseAddresses)
    {
        return new DIServiceHost(serviceType, baseAddresses);
    }
}





The custom ServiceHostFactory class can now be used in the ServiceHost file required when doing IIS hosting:




  
<%@ ServiceHost Language="C#" 
                Debug="true" 
                Service="WindsorService.MyWindsorService" 
                Factory="WindsorService.DIServiceHostFactory"
                CodeBehind="MyWindsorService.svc.cs" %>





There is also another way for achieving this that I will be investigating the next week or so using the WCF Integration Facility for Castle Windsor. For some reason it is not available in the current release of the Castle stack so I have to grab it from the trunk. 



If you have any thoughts, improvements or suggestions I'm glad to hear them from you, my dear reader. It's the only way I'll ever learn :-). 



Till next time.
]]>
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		9
		
		
		Elegant Code » NHibernate
	
	http://elegantcode.com
	
	Tue, 15 May 2012 10:00:00 +0000
	en
	hourly
	1
	http://wordpress.org/?v=3.3.1
		
		FubuMVC From Scratch – Part 4 Persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments
		Wed, 25 Mar 2009 21:22:00 +0000
		Ryan Kelley
				
		
		
		
		
		
		

		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/
		
			Previous posts in series:    
Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project
  
We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.
  
Class and Interfaces we have to implement: 
  
       
  • ISessionSourceConfiguration 
    •     
  • SQLServerSessionSourceConfiguration 
    •     
  • IUnitOfWork 
    •     
  • INHibernateUnitOfWork 
    •     
  • NHibernateUnitOfWork 
    •     
  • IRepository 
    •     
  • NHibernateRepository 
    •     
  • DomainEntity 
    •     
  • IDomainQuery 
    •     
  • FubuSamplePersistenceModel 
    •  
  
Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence
  
Before we start you probably want to go ahead and add the following references to your core project and Web project
  
FubuMVC-Persist-Ref 
  
Let’s just work our way down the list and get these files implemented. 
  
ISessionSourceConfiguration
  
   
     
public interface ISessionSourceConfiguration


    
{


    
    bool IsNewDatabase { get; }


    
    ISessionSource CreateSessionSource(PersistenceModel model);


    
}

  





SQLServerSessionSourceConfiguration




  

    
public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration


    
{


    
    #region Implementation of ISessionSourceConfiguration


    
 


    
    public bool IsNewDatabase


    
    {


    
        get { return false; }


    
    }


    
 


    
    public ISessionSource CreateSessionSource(PersistenceModel model)


    
    {


    
        var properties = GetProperties();


    
        var source = new SessionSource(properties, model);


    
 


    
        create_schema_if_it_does_not_already_exist(source);


    
 


    
        return source;


    
    }


    
 


    
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)


    
    {


    
        if (IsNewDatabase) source.BuildSchema();


    
    }


    
 


    
    protected IDictionary<string, string> GetProperties()


    
    {


    
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;


    
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);


    
        config.ShowSql();


    
        config.UseOuterJoin();


    
 


    
        return config.ToProperties();


    
    }


    
    #endregion


    
}

  





A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.



IUnitOfWork




  

    
public interface IUnitOfWork : IDisposable


    
{


    
    void Initialize();


    
    void Commit();


    
    void Rollback();


    
}

  





INHibernateUnitOfWork




  

    
public interface INHibernateUnitOfWork : IUnitOfWork


    
{


    
    ISession CurrentSession { get; }


    
}

  





NHibernateUnitOfWork




  

    
public class NHibernateUnitOfWork : INHibernateUnitOfWork


    
{


    
    private ITransaction _transaction;


    
    private bool _isDisposed;


    
    private readonly ISessionSource _source;


    
    private bool _isInitialized;


    
 


    
    public NHibernateUnitOfWork(ISessionSource source)


    
    {


    
        _source = source;


    
    }


    
 


    
    public void Initialize()


    
    {


    
        should_not_currently_be_disposed();


    
 


    
        CurrentSession = _source.CreateSession();


    
        begin_new_transaction();


    
 


    
        _isInitialized = true;


    
    }


    
 


    
    public ISession CurrentSession { get; private set; }


    
 


    
    public void Commit()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Commit();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void begin_new_transaction()


    
    {


    
        if (_transaction != null)


    
        {


    
            _transaction.Dispose();


    
        }


    
 


    
        _transaction = CurrentSession.BeginTransaction();


    
    }


    
 


    
    public void Rollback()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Rollback();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void should_not_currently_be_disposed()


    
    {


    
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);


    
    }


    
 


    
    private void should_be_initialized_first()


    
    {


    
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");


    
    }


    
 


    
    public void Dispose()


    
    {


    
        if (_isDisposed || !_isInitialized) return;


    
 


    
        _transaction.Dispose();


    
        CurrentSession.Dispose();


    
 


    
        _isDisposed = true;


    
    }


    
}

  





IRepository




  

    
public interface IRepository


    
{


    
    void Save<ENTITY>(ENTITY entity)


    
        where ENTITY : DomainEntity;


    
 


    
    ENTITY Load<ENTITY>(Guid id)


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>()


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)


    
        where ENTITY : DomainEntity;


    
 


    
    void Delete<ENTITY>(ENTITY entity);


    
 


    
    void DeleteAll<ENTITY>();


    
}

  





NHibernateRepository




  

    
public class NHibernateRepository : IRepository


    
{


    
    private readonly INHibernateUnitOfWork _unitOfWork;


    
 


    
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity


    
    {


    
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);


    
    }


    
 


    
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>();


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);


    
    }


    
 


    
    public void Delete<ENTITY>(ENTITY entity)


    
    {


    
        _unitOfWork.CurrentSession.Delete(entity);   


    
    }


    
 


    
    public void DeleteAll<ENTITY>()


    
    {


    
        var query = String.Format("from {0}", typeof(ENTITY).Name);


    
        _unitOfWork.CurrentSession.Delete(query);   


    
    }


    
}

  





DomainEntity



Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository




  

    
public class DomainEntity : IEquatable<DomainEntity>


    
{


    
    public virtual Guid ID { get; set; }


    
 


    
    public virtual bool Equals(DomainEntity other)


    
    {


    
        if (ReferenceEquals(null, other)) return false;


    
        if (ReferenceEquals(this, other)) return true;


    
        return other.ID.Equals(ID);


    
    }


    
 


    
    public override bool Equals(object obj)


    
    {


    
        if (ReferenceEquals(null, obj)) return false;


    
        if (ReferenceEquals(this, obj)) return true;


    
        if (obj.GetType() != GetType()) return false;


    
        return Equals((DomainEntity)obj);


    
    }


    
 


    
    public override int GetHashCode()


    
    {


    
        return ID.GetHashCode();


    
    }


    
 


    
    public static bool operator ==(DomainEntity left, DomainEntity right)


    
    {


    
        return Equals(left, right);


    
    }


    
 


    
    public static bool operator !=(DomainEntity left, DomainEntity right)


    
    {


    
        return !Equals(left, right);


    
    }


    
}

  





IDomainQuery




  

    
public interface IDomainQuery<ENTITY>


    
    where ENTITY : DomainEntity


    
{


    
    Expression<Func<ENTITY, bool>> Expression { get; }


    
}

  





FubuSamplePersistenceModel




  

    
namespace FubuSample.Core.Domain.Persistence


    
{


    
    public class FubuSamplePersistenceModel : PersistenceModel


    
    {


    
        public FubuSamplePersistenceModel()


    
        {


    
            addMappingsFromThisAssembly();


    
        }


    
    }


    
}

  





Now that we have all the puzzle pieces in place we need to hook them up and make them do some work. Open up FubuSampleWebRegistry 



And add the following code:




  

    
protected override void configure()


    
{


    
    ForRequestedType<ISessionSourceConfiguration>().AsSingletons()


    
        .TheDefault.Is.OfConcreteType<SQLServerSessionSourceConfiguration>();


    
 


    
 


    
    ForRequestedType<ISessionSource>().AsSingletons()


    
        .TheDefault.Is.ConstructedBy(ctx =>


    
                                     ctx.GetInstance<ISessionSourceConfiguration>()


    
                                         .CreateSessionSource(new FubuSamplePersistenceModel()));


    
 


    
    ForRequestedType<IUnitOfWork>().TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<INHibernateUnitOfWork>());


    
 


    
    ForRequestedType<INHibernateUnitOfWork>().CacheBy(InstanceScope.Hybrid)


    
        .TheDefault.Is.OfConcreteType<NHibernateUnitOfWork>();


    
 


    
    ForRequestedType<IRepository>().TheDefault.Is.OfConcreteType<NHibernateRepository>();


    
}

  





With a little luck and all of our mad skills, we should be able to talk to the database now. So we need to plumb our simple product object up to talk to NHibernate. We will do this with a mapping file, and since we are using FluentNHibernate we can do this strongly typed.



Make the following modifications to Product: Extend DomainEntity and get rid of Id Property, it is inherited




  

    
public class Product : DomainEntity


    
{


    
    public virtual string Name { get; set; }


    
    public virtual string Description { get; set; }


    
}

  





Add mapping file for Product:




  

    
namespace FubuSample.Core.Domain.Mapping


    
{


    
    public class ProductMap : ClassMap<Product>


    
    {


    
        public ProductMap()


    
        {


    
            Id(e => e.ID).GeneratedBy.GuidComb();


    
 


    
            Map(p => p.Name);


    
            Map(p => p.Description);


    
            


    
        }


    
    }


    
}

  





You may also want to setup your connection string at this point in the Web.Config file, mine looks like this:




  

    
<add name="MYDBKEY" connectionString="Data Source=LOCALHOST;initial catalog=FubuSample;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />

  





I also created an empty database in my local SQL Server instance called “FubuSample” And then I went back to SQLServerSessionSourceConfiguration and changed the value of IsNewDatabase to return true. This will create the schema for the database when the application first runs. There is a multitude of different ways that we can handle this, but this was easy for the tutorial purposes.



Next we will add a behavior to our core project and tell FubuMVC to apply that behavior to all or our ControllerActions.



Create a class named “access_the_database_through_a_unit_of_work” in your Core.Web.Behaviors namespace. The contents will look like this:




  

    
public class access_the_database_through_a_unit_of_work : IControllerActionBehavior


    
{


    
    private readonly IUnitOfWork _unitOfWork;


    
 


    
    public access_the_database_through_a_unit_of_work(IUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public IControllerActionBehavior InsideBehavior { get; set; }


    
    public IInvocationResult Result { get; set; }


    
 


    
    public OUTPUT Invoke<INPUT, OUTPUT>(INPUT input, Func<INPUT, OUTPUT> func)


    
        where INPUT : class


    
        where OUTPUT : class


    
    {


    
        _unitOfWork.Initialize();


    
 


    
        try


    
        {


    
            var output = InsideBehavior.Invoke(input, func);


    
            Result = InsideBehavior.Result;


    
 


    
            _unitOfWork.Commit();


    
 


    
            return output;


    
        }


    
        catch


    
        {


    
            _unitOfWork.Rollback();


    
            throw;


    
        }


    
        finally


    
        {


    
            _unitOfWork.Dispose();


    
        }


    
    }


    
}

  





Now to tell FubuMVC what to do, open up Global.asax.cs or your Bootstrapper, wherever you are doing the configuration of FubuMVC. In this project we are doing it in Global.asax.cs Add a new behavior to the section that starts with “x.ByDefault.EveryControllerAction” so it looks like this:




  

    
x.ByDefault.EveryControllerAction(d =>


    
   {


    
       d.Will<execute_the_result>();


    
       d.Will<access_the_database_through_a_unit_of_work>();


    
   });

  





The last thing we will do is open up HomeController and add this code above the Index action:




  

    
private IRepository _repository;


    
 


    
public HomeController(IRepository repository)


    
{


    
    _repository = repository;


    
}

  





I also modified the Index action to go ahead and create some database values before we query for them just so we can test this thing. (I only did this for the tutorial, I swear) So modify the Index action to look like this:




  

    
public IndexViewModel Index(IndexSetupViewModel inModel)


    
{


    
    var prod1 = new Product {Name = "TestProduct1", Description = "This is a test product"};


    
 


    
    _repository.Save(prod1);


    
 


    
    var prod2 = new Product {Name = "TestProduct2", Description = "This is a test product"};


    
 


    
    _repository.Save(prod2);


    
 


    
    var outModel = new IndexViewModel();


    
 


    
    var productList = _repository.Query<Product>();


    
 


    
    outModel.Products = productList.ToList().Select(x => new ProductDisplay(x));


    
 


    
    return outModel;


    
}

  





Now with you should be able to run your web app and browse to /home and all this will be executed and you will be on your way to creating a whole bunch of persist able objects for use with your FubuMVC app.



As always, feedback is welcome.
]]>
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		9
		
		
		Book review: NHibernate in Action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/?utm_source=rss&utm_medium=rss&utm_campaign=book-review-nhibernate-in-action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/#comments
		Sat, 14 Jun 2008 20:42:15 +0000
		Jan Van Ryswyck
				
		
		

		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/
		
			kuate_cover150 Writing this book review feels kind of weird  because it hasn't actually hit the shelves yet. It is accessible however through the Manning Early Access Program. This book provides a clear insight of using NHibernate as the data access layer of your applications and beyond. 
 
The excessive amount of NHibernate features  isn't the only thing that is written down. There is also a good coverage of OO principles and Domain-Driven Design, although it isn't the primary objective of the book of course. This is especially true for the first and the last three chapters. If you've already read the nominal books DDD and you are familiar with Persistence Ignorance, then you can safely skim through these chapters unless you want to see the interpretation of the authors when it comes to these principles. If you are new to these concepts, then these chapters are of great value to wet your appetite.
 
Although this book covers a lot of ground, I would certainly recommend it when you're rather new to NHibernate and ORM's in general. I guess this still includes me, although I've been using NHibernate for quite some time now. If you already have some experience with NHibernate, then this book probably doesn't teach you that much. Still, it can quickly get you up to speed when you want to use a particular feature that you haven't used before. 
 
The only minor thing about this book is that I'm afraid that it will soon be out-of-date. The book only covers NHibernate 1.2.x and no features from the upcoming 2.0 release, which adds a lot of new and interesting features. It would be nice if the book already covered some of these features as most of them are ported from Hibernate itself, which is the original Java version.
 
On the other hand, this book provides an in-depth view of the basic features of NHibernate, which aren't necessarily going to change that much over time anyway.
 
Let me round off this post by saying that I'm really impressed by the list of books that Manning is going to release the next couple of months. These are the ones that I'm particularly interested in:
  
I already bought LINQ in Action and also read a lot of good things about C# in Depth, which I'm going to pick up soon.
 
Take care.
]]>
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		7
		
		
		Integrating Castle Windsor and NHibernate with WCF
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/?utm_source=rss&utm_medium=rss&utm_campaign=integrating-castle-windsor-and-nhibernate-with-wcf
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/#comments
		Sun, 18 May 2008 14:08:20 +0000
		Jan Van Ryswyck
				
		

		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/
		
			Up until now, we were using the NHibernate facility of Castle Windsor for managing our NHibernate sessions in WCF. But, we want to have a session-per-request approach as one would use when integrating NHibernate with a regular web application. 
  
Yesterday I did a small spike to figure out how this should work. It turned out to be pretty easy. I used this excellent blog post written by Oran Dennison as my guide. 
  
First I created a class that implemented the IServiceBehavior interface.
  
   
public class DIServiceBehavior : IServiceBehavior
{
    private readonly ISessionFactory _sessionFactory;

    public DIServiceBehavior()
    {
        _sessionFactory = new Configuration()
            .Configure()
            .BuildSessionFactory();

        XmlConfigurator.Configure();    // Log4Net
    }

    public void ApplyDispatchBehavior(
             ServiceDescription serviceDescription, 
             ServiceHostBase serviceHostBase)
    {
        foreach(ChannelDispatcherBase cdb in 
                serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if(cd != null)
            {
                foreach(EndpointDispatcher ed in cd.Endpoints)
                {
                    ed.DispatchRuntime.InstanceProvider =
                        new DIInstanceProvider
                            (serviceDescription.ServiceType,
                              _sessionFactory);
                }
            }
        }
    }

    public void AddBindingParameters(
                ServiceDescription serviceDescription, 
                ServiceHostBase serviceHostBase,
                Collection<ServiceEndpoint> endpoints, 
                BindingParameterCollection bindingParameters) 
    { }
    
    public void Validate(ServiceDescription serviceDescription, 
                         ServiceHostBase serviceHostBase) 
    { }
}





The SessionFactory is created in the constructor because the ApplyDispatchBehaviour method can be called multiple times (for each endpoint). 



The next step is to create an instance provider by creating a class that implements the IInstanceProvider:




  
public class DIInstanceProvider : IInstanceProvider
{
    private const String NHibernateSessionKey = 
        "NHibernate.Session";

    private readonly Type _serviceType;
    private IDependencyContainer _dependencyContainer;
    private readonly ISessionFactory _sessionFactory;
    private ISession _session;

    public DIInstanceProvider(Type serviceType,
                               ISessionFactory sessionFactory)
    {
        Debug.Assert(null != serviceType, 
                     "null != serviceType");
        _serviceType = serviceType;

        Debug.Assert(null != sessionFactory, 
                     "null = sessionFactory");
        _sessionFactory = sessionFactory;
    }

    public Object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public Object GetInstance(InstanceContext instanceContext, 
                                Message message)
    {
        _dependencyContainer = new DependencyContainer();

        _session = _sessionFactory.OpenSession();
        _dependencyContainer
          .AddComponentInstance(NHibernateSessionKey, _session);

        return _dependencyContainer.Resolve(_serviceType);
    }

    public void ReleaseInstance(InstanceContext instanceContext, 
                                 Object instance)
    {
        if(null != _session)
        {
            _session.Close();
            _session = null;
        }

        if(null != _dependencyContainer)
        {
            _dependencyContainer.Dispose();
            _dependencyContainer = null;
        }
    }
}





I created a wrapper class around for Castle Windsor named DependencyContainer.  The GetInstance method opens a new session using the SessionFactory object we instantiated in the service behavior class. The session object is then registered with Castle Windsor. We can now implement our repositories like this:




  
public class SomeAggregateRepository
{
    private ISession _session;

    public SomeAggregateRepository(ISession session)
    {
        _session = session;
    }
    
    public SomeAggregate Get(Int64 id) 
    {
        return _session.Get<SomeAggregate>(id);
    }
}





When our service operation has been executed, the NHibernate is released by the ReleaseInstance method. Finishing our example, we need to implement a custom ServiceHost and a ServiceHostFactory:




  
public class DIServiceHost : ServiceHost
{
    public DependencyInjectionServiceHost() 
        : base() 
    { }
    
    public DIServiceHost(Type serviceType, 
                         params Uri[] baseAddresses) 
        : base(serviceType, baseAddresses) 
    { }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new DIServiceBehavior());
        base.OnOpening();
    }
}

public class DIServiceHostFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(
            Type serviceType, Uri[] baseAddresses)
    {
        return new DIServiceHost(serviceType, baseAddresses);
    }
}





The custom ServiceHostFactory class can now be used in the ServiceHost file required when doing IIS hosting:




  
<%@ ServiceHost Language="C#" 
                Debug="true" 
                Service="WindsorService.MyWindsorService" 
                Factory="WindsorService.DIServiceHostFactory"
                CodeBehind="MyWindsorService.svc.cs" %>





There is also another way for achieving this that I will be investigating the next week or so using the WCF Integration Facility for Castle Windsor. For some reason it is not available in the current release of the Castle stack so I have to grab it from the trunk. 



If you have any thoughts, improvements or suggestions I'm glad to hear them from you, my dear reader. It's the only way I'll ever learn :-). 



Till next time.
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		9
		
		
		Implementing NHibernate Interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/?utm_source=rss&utm_medium=rss&utm_campaign=implementing-nhibernate-interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/#comments
		Thu, 15 May 2008 18:29:26 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/
		
			One of the areas where NHibernate really shines is it's high extensibility features. The NHibernate API provides a massive amount of interfaces that can be implemented for your own custom extension pleasure. 
  
For me this is a nice change as opposed to the many sealed API's put out by the Redmond collective (WCF being the exception, the Entity Framework confirming the rule).
  
Anyhow, with great power comes great responsibility. Today I encountered a rather difficult problem with NHibernate that could have been easily prevented by reading the documentation (note to self: use the CTRL-Q shortcut of Resharper more often).
  
We have implemented an interceptor for automatically configuring audit information as described by this great post from Ray Houston. 
  
   
public class AuditInformationInterceptor 
    : EmptyInterceptor
{
    Boolean OnSave(Object entity, Object id, Object[] state, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }

    Boolean OnFlushDirty(Object entity, Object id, 
        Object[] currentState, Object[] previousState, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }                  
}





The mistake we made is that we manipulated the audit information of the entity directly in the OnSave and OnFlushDirty methods. This only became apparent when saving an aggregate root with his child entities. Everything worked fine until we wanted to persist one of the child entities that should have been a piece of cake but turned out to be the messenger of trouble. NHibernate refused to perform an INSERT statement, but instead threw an UPDATE statement at us. 



After some debugging we found out that the audit information should have been manipulated through the state and currentState arguments of the OnSave and OnFlushDirty methods respectively.



The documentation of the OnSave method clearly states:



The interceptor may modify the state, which will be used for the SQL INSERT

    
and propagated to the persistent object



Lesson relearned. 



I'm off, reading some docs. Until next time.
]]>
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		3
		
		
		On Persistence
		http://elegantcode.com/2008/05/01/on-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=on-persistence
		http://elegantcode.com/2008/05/01/on-persistence/#comments
		Thu, 01 May 2008 19:18:43 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/01/on-persistence/
		
			Earlier this week, I managed to convince our very wise decision makers to start using NHibernate for our persistence layer. My team mate on the project describes how it went. While I was reading Jeremy's train of thoughts, the following four lines made me realize we did the right thing:
  
Why are teams still writing persistence code by hand?  There's a bazillion persistence tools out there that all save development costs in some way over writing data access code by hand.  With very few exceptions, I'd say that at this point that if you're writing ADO.Net code or SQL by hand, you're stealing money from your employer.  
  
As another co-worker and NHibernate fan thoughtfully mentioned while congratulating us:
  
A small step for man, but a giant leap for mankind.
  
Few. What a week this turns out to be.
]]>
			http://elegantcode.com/2008/05/01/on-persistence/feed/
		2
		
		
		NHibernate 2.0 and Cascading Deletes
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-20-and-cascading-deletes-2
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/#comments
		Sat, 12 Apr 2008 18:58:12 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/
		
			The first alpha version of NHibernate 2.0 has been released some time ago. Oren has put a nice overview of the new features and the bugs that are solved for this first drop. In spite the fact that they put the word 'alpha' in the version name, it is actually RTM quality! 
  
One of the great new additions is the on-delete attribute of the key element for mapping collections:
  
<set name="Permissions" inverse="true" cascade="save-update">
  <key name="Authorization" on-delete="cascade"/>
  <one-to-many class="Permission"/>
</set>



This particular feature solves the issue I've had with one-shot deletes on inverse collections (which I described here). Configuring it this way ensures that NHibernate relies on database-level ON CASCADE DELETE foreign key constraints. This implies that when an object with a collection of child objects is deleted, a single DELETE  statement is used to remove all children at once instead of individual DELETE statements for each child object (which are called orphans at this point).



There are some things that you have to take into account here. First, this option bypasses NHibernate's optimistic locking strategy for versioned data. Second, make sure that you configure cascade="save-update" instead of cascade="all" to prevent NHibernate from performing delete cascade checks. This is important when lazy loading is enabled for the collection because it prevents that NHibernate loads one-to-many associations into memory. 



I'm really excited about this new release. Kudos to the men and women who have put so much effort in building such a wonderful ORM solution!



Till next time
]]>
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		0
		
		
		A New NHibernate Blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/?utm_source=rss&utm_medium=rss&utm_campaign=a-new-nhibernate-blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/#comments
		Tue, 01 Apr 2008 15:26:32 +0000
		Alex Mueller
				
		
		
		

		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/
		
			Craig Neuwirt recently started a blog focused on NHibernate, as mentioned by Ayende. NHibernate is an ORM tool I have used on current and past projects and it is something I feel I would like I want to study further. So far, Craig is walking us through NHibernate from the ground-up, with the latest and greatest. I anticipate this being an informative blog to follow.

The NHibernate FAQ
Craig Neuwirt
Hibernating Rhinos]]>
			http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/feed/
		2
		
		
		NHibernate IQuery to ISQLQuery Black Magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-iquery-to-isqlquery-black-magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/#comments
		Fri, 16 Nov 2007 06:12:55 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/
		
			posted on the forums and learned that: I'd run into a known bug / limitation.

Therefore I resorted to using ISQLQuery (yuk). I fixed several repository methods and then I ran into a very complicated IQuery. It was very painful to write the first time. In fact it was this experience that had caused me to change to using ICriteria as my default query method with specifications. I had a full suite of unit tests to protect me so I was confident that I could make the changes without breaking anything but I didn't want to do the conversion manually. Surely there was a trick?

It turns out that there is - NHibernate.Hql.Classic.QueryTranslator. The property that I needed is protected but thanks to a quick search of the forums I didn't even need to write my own reflection based method of calling it because someone had done it for me (thanks Nels). So what I did was take the HQL and convert it to SQL. I then did some string replacement to morph the SQL into what I needed. I am not proud of this but it was fast and it goes to show for flexible NHibernate is if you want to do some certifiable things.]]>
			http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/feed/
		0
		
		
		DTOs / Presentation Model and ICriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/?utm_source=rss&utm_medium=rss&utm_campaign=dtos-presentation-model-and-icriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/#comments
		Tue, 06 Nov 2007 06:11:41 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/
		
			NHibernate Projections I used HQL (IQuery) in the repository to define the query.

There are a some things that I don't like about HQL. For example the query is defined as a string. Strings are problematic because errors can't be detected at compile time. ICriteria queries go some way to alleviating this although they are certainly not perfect in this regard. You are writing tests against your repositories though aren't you?

But the reliance on strings is not the only problem with HQL. Today I needed to create a search screen. I wanted to use a variation of the technique that Ayende demonstrates here. With HQL the repository methods become ugly very quickly (and I mean wake up sweating at 2 am ugly). There is a mass of conditional string concatenation. And for each parameter I need to change 2 pieces of code (the code that builds the HQL and the code that binds the parameters).

So I decided to figure out how to use ICriteria to return a DTO. It transpires that the following code produces the same result as the HQL that I used before:

 



public List<InspectorDropDownDTO> GetAll()


{


 ICriteria q = session.CreateCriteria(typeof(Inspector), "i");


 q.CreateAlias("Person", "p");


 q.SetProjection(Projections.ProjectionList()


 .Add(Projections.Property("i.ID"), "InspectorID")


 .Add(Projections.Property("p.FirstName"), "FirstName")


 .Add(Projections.Property("p.LastName"), "LastName"));


 q.SetResultTransformer(Transformers.AliasToBean(typeof(InspectorDropDownDTO)));


 return q.List<InspectorDropDownDTO>();


}

It should be noted that the DTO itself is different with this method. A default constructor is now all that's needed because the AliasToBean transformer seems to work properly with ICriteria.

 



public class InspectorDropDownDTO


{


 private long _inspectorID;


 private string _firstName;


 private string _lastName;




 public long InspectorID { get { return _inspectorID; } set { _inspectorID = value; } }


 public string FirstName { get { return _firstName; } set { _firstName = value; } }


 public string LastName { get { return _lastName; } set { _lastName = value; } }


 public string FullName { get { return FirstName + " " + LastName; } }


}

Also note that you no longer need to import the DTO in an hbm.xml file.]]>
			http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/feed/
		2
		
		
		DTOs Simplify Complex Screens
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/?utm_source=rss&utm_medium=rss&utm_campaign=implementing-nhibernate-interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/#comments
		Thu, 15 May 2008 18:29:26 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/
		
			One of the areas where NHibernate really shines is it's high extensibility features. The NHibernate API provides a massive amount of interfaces that can be implemented for your own custom extension pleasure. 
  
For me this is a nice change as opposed to the many sealed API's put out by the Redmond collective (WCF being the exception, the Entity Framework confirming the rule).
  
Anyhow, with great power comes great responsibility. Today I encountered a rather difficult problem with NHibernate that could have been easily prevented by reading the documentation (note to self: use the CTRL-Q shortcut of Resharper more often).
  
We have implemented an interceptor for automatically configuring audit information as described by this great post from Ray Houston. 
  
   
public class AuditInformationInterceptor 
    : EmptyInterceptor
{
    Boolean OnSave(Object entity, Object id, Object[] state, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }

    Boolean OnFlushDirty(Object entity, Object id, 
        Object[] currentState, Object[] previousState, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }                  
}





The mistake we made is that we manipulated the audit information of the entity directly in the OnSave and OnFlushDirty methods. This only became apparent when saving an aggregate root with his child entities. Everything worked fine until we wanted to persist one of the child entities that should have been a piece of cake but turned out to be the messenger of trouble. NHibernate refused to perform an INSERT statement, but instead threw an UPDATE statement at us. 



After some debugging we found out that the audit information should have been manipulated through the state and currentState arguments of the OnSave and OnFlushDirty methods respectively.



The documentation of the OnSave method clearly states:



The interceptor may modify the state, which will be used for the SQL INSERT

    
and propagated to the persistent object



Lesson relearned. 



I'm off, reading some docs. Until next time.
]]>
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		3
		
		
		Elegant Code » NHibernate
	
	http://elegantcode.com
	
	Tue, 15 May 2012 10:00:00 +0000
	en
	hourly
	1
	http://wordpress.org/?v=3.3.1
		
		FubuMVC From Scratch – Part 4 Persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments
		Wed, 25 Mar 2009 21:22:00 +0000
		Ryan Kelley
				
		
		
		
		
		
		

		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/
		
			Previous posts in series:    
Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project
  
We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.
  
Class and Interfaces we have to implement: 
  
       
  • ISessionSourceConfiguration 
    •     
  • SQLServerSessionSourceConfiguration 
    •     
  • IUnitOfWork 
    •     
  • INHibernateUnitOfWork 
    •     
  • NHibernateUnitOfWork 
    •     
  • IRepository 
    •     
  • NHibernateRepository 
    •     
  • DomainEntity 
    •     
  • IDomainQuery 
    •     
  • FubuSamplePersistenceModel 
    •  
  
Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence
  
Before we start you probably want to go ahead and add the following references to your core project and Web project
  
FubuMVC-Persist-Ref 
  
Let’s just work our way down the list and get these files implemented. 
  
ISessionSourceConfiguration
  
   
     
public interface ISessionSourceConfiguration


    
{


    
    bool IsNewDatabase { get; }


    
    ISessionSource CreateSessionSource(PersistenceModel model);


    
}

  





SQLServerSessionSourceConfiguration




  

    
public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration


    
{


    
    #region Implementation of ISessionSourceConfiguration


    
 


    
    public bool IsNewDatabase


    
    {


    
        get { return false; }


    
    }


    
 


    
    public ISessionSource CreateSessionSource(PersistenceModel model)


    
    {


    
        var properties = GetProperties();


    
        var source = new SessionSource(properties, model);


    
 


    
        create_schema_if_it_does_not_already_exist(source);


    
 


    
        return source;


    
    }


    
 


    
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)


    
    {


    
        if (IsNewDatabase) source.BuildSchema();


    
    }


    
 


    
    protected IDictionary<string, string> GetProperties()


    
    {


    
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;


    
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);


    
        config.ShowSql();


    
        config.UseOuterJoin();


    
 


    
        return config.ToProperties();


    
    }


    
    #endregion


    
}

  





A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.



IUnitOfWork




  

    
public interface IUnitOfWork : IDisposable


    
{


    
    void Initialize();


    
    void Commit();


    
    void Rollback();


    
}

  





INHibernateUnitOfWork




  

    
public interface INHibernateUnitOfWork : IUnitOfWork


    
{


    
    ISession CurrentSession { get; }


    
}

  





NHibernateUnitOfWork




  

    
public class NHibernateUnitOfWork : INHibernateUnitOfWork


    
{


    
    private ITransaction _transaction;


    
    private bool _isDisposed;


    
    private readonly ISessionSource _source;


    
    private bool _isInitialized;


    
 


    
    public NHibernateUnitOfWork(ISessionSource source)


    
    {


    
        _source = source;


    
    }


    
 


    
    public void Initialize()


    
    {


    
        should_not_currently_be_disposed();


    
 


    
        CurrentSession = _source.CreateSession();


    
        begin_new_transaction();


    
 


    
        _isInitialized = true;


    
    }


    
 


    
    public ISession CurrentSession { get; private set; }


    
 


    
    public void Commit()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Commit();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void begin_new_transaction()


    
    {


    
        if (_transaction != null)


    
        {


    
            _transaction.Dispose();


    
        }


    
 


    
        _transaction = CurrentSession.BeginTransaction();


    
    }


    
 


    
    public void Rollback()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Rollback();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void should_not_currently_be_disposed()


    
    {


    
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);


    
    }


    
 


    
    private void should_be_initialized_first()


    
    {


    
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");


    
    }


    
 


    
    public void Dispose()


    
    {


    
        if (_isDisposed || !_isInitialized) return;


    
 


    
        _transaction.Dispose();


    
        CurrentSession.Dispose();


    
 


    
        _isDisposed = true;


    
    }


    
}

  





IRepository




  

    
public interface IRepository


    
{


    
    void Save<ENTITY>(ENTITY entity)


    
        where ENTITY : DomainEntity;


    
 


    
    ENTITY Load<ENTITY>(Guid id)


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>()


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)


    
        where ENTITY : DomainEntity;


    
 


    
    void Delete<ENTITY>(ENTITY entity);


    
 


    
    void DeleteAll<ENTITY>();


    
}

  





NHibernateRepository




  

    
public class NHibernateRepository : IRepository


    
{


    
    private readonly INHibernateUnitOfWork _unitOfWork;


    
 


    
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity


    
    {


    
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);


    
    }


    
 


    
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>();


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);


    
    }


    
 


    
    public void Delete<ENTITY>(ENTITY entity)


    
    {


    
        _unitOfWork.CurrentSession.Delete(entity);   


    
    }


    
 


    
    public void DeleteAll<ENTITY>()


    
    {


    
        var query = String.Format("from {0}", typeof(ENTITY).Name);


    
        _unitOfWork.CurrentSession.Delete(query);   


    
    }


    
}

  





DomainEntity



Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository




  

    
public class DomainEntity : IEquatable<DomainEntity>


    
{


    
    public virtual Guid ID { get; set; }


    
 


    
    public virtual bool Equals(DomainEntity other)


    
    {


    
        if (ReferenceEquals(null, other)) return false;


    
        if (ReferenceEquals(this, other)) return true;


    
        return other.ID.Equals(ID);


    
    }


    
 


    
    public override bool Equals(object obj)


    
    {


    
        if (ReferenceEquals(null, obj)) return false;


    
        if (ReferenceEquals(this, obj)) return true;


    
        if (obj.GetType() != GetType()) return false;


    
        return Equals((DomainEntity)obj);


    
    }


    
 


    
    public override int GetHashCode()


    
    {


    
        return ID.GetHashCode();


    
    }


    
 


    
    public static bool operator ==(DomainEntity left, DomainEntity right)


    
    {


    
        return Equals(left, right);


    
    }


    
 


    
    public static bool operator !=(DomainEntity left, DomainEntity right)


    
    {


    
        return !Equals(left, right);


    
    }


    
}

  





IDomainQuery




  

    
public interface IDomainQuery<ENTITY>


    
    where ENTITY : DomainEntity


    
{


    
    Expression<Func<ENTITY, bool>> Expression { get; }


    
}

  





FubuSamplePersistenceModel




  

    
namespace FubuSample.Core.Domain.Persistence


    
{


    
    public class FubuSamplePersistenceModel : PersistenceModel


    
    {


    
        public FubuSamplePersistenceModel()


    
        {


    
            addMappingsFromThisAssembly();


    
        }


    
    }


    
}

  





Now that we have all the puzzle pieces in place we need to hook them up and make them do some work. Open up FubuSampleWebRegistry 



And add the following code:




  

    
protected override void configure()


    
{


    
    ForRequestedType<ISessionSourceConfiguration>().AsSingletons()


    
        .TheDefault.Is.OfConcreteType<SQLServerSessionSourceConfiguration>();


    
 


    
 


    
    ForRequestedType<ISessionSource>().AsSingletons()


    
        .TheDefault.Is.ConstructedBy(ctx =>


    
                                     ctx.GetInstance<ISessionSourceConfiguration>()


    
                                         .CreateSessionSource(new FubuSamplePersistenceModel()));


    
 


    
    ForRequestedType<IUnitOfWork>().TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<INHibernateUnitOfWork>());


    
 


    
    ForRequestedType<INHibernateUnitOfWork>().CacheBy(InstanceScope.Hybrid)


    
        .TheDefault.Is.OfConcreteType<NHibernateUnitOfWork>();


    
 


    
    ForRequestedType<IRepository>().TheDefault.Is.OfConcreteType<NHibernateRepository>();


    
}

  





With a little luck and all of our mad skills, we should be able to talk to the database now. So we need to plumb our simple product object up to talk to NHibernate. We will do this with a mapping file, and since we are using FluentNHibernate we can do this strongly typed.



Make the following modifications to Product: Extend DomainEntity and get rid of Id Property, it is inherited




  

    
public class Product : DomainEntity


    
{


    
    public virtual string Name { get; set; }


    
    public virtual string Description { get; set; }


    
}

  





Add mapping file for Product:




  

    
namespace FubuSample.Core.Domain.Mapping


    
{


    
    public class ProductMap : ClassMap<Product>


    
    {


    
        public ProductMap()


    
        {


    
            Id(e => e.ID).GeneratedBy.GuidComb();


    
 


    
            Map(p => p.Name);


    
            Map(p => p.Description);


    
            


    
        }


    
    }


    
}

  





You may also want to setup your connection string at this point in the Web.Config file, mine looks like this:




  

    
<add name="MYDBKEY" connectionString="Data Source=LOCALHOST;initial catalog=FubuSample;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />

  





I also created an empty database in my local SQL Server instance called “FubuSample” And then I went back to SQLServerSessionSourceConfiguration and changed the value of IsNewDatabase to return true. This will create the schema for the database when the application first runs. There is a multitude of different ways that we can handle this, but this was easy for the tutorial purposes.



Next we will add a behavior to our core project and tell FubuMVC to apply that behavior to all or our ControllerActions.



Create a class named “access_the_database_through_a_unit_of_work” in your Core.Web.Behaviors namespace. The contents will look like this:




  

    
public class access_the_database_through_a_unit_of_work : IControllerActionBehavior


    
{


    
    private readonly IUnitOfWork _unitOfWork;


    
 


    
    public access_the_database_through_a_unit_of_work(IUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public IControllerActionBehavior InsideBehavior { get; set; }


    
    public IInvocationResult Result { get; set; }


    
 


    
    public OUTPUT Invoke<INPUT, OUTPUT>(INPUT input, Func<INPUT, OUTPUT> func)


    
        where INPUT : class


    
        where OUTPUT : class


    
    {


    
        _unitOfWork.Initialize();


    
 


    
        try


    
        {


    
            var output = InsideBehavior.Invoke(input, func);


    
            Result = InsideBehavior.Result;


    
 


    
            _unitOfWork.Commit();


    
 


    
            return output;


    
        }


    
        catch


    
        {


    
            _unitOfWork.Rollback();


    
            throw;


    
        }


    
        finally


    
        {


    
            _unitOfWork.Dispose();


    
        }


    
    }


    
}

  





Now to tell FubuMVC what to do, open up Global.asax.cs or your Bootstrapper, wherever you are doing the configuration of FubuMVC. In this project we are doing it in Global.asax.cs Add a new behavior to the section that starts with “x.ByDefault.EveryControllerAction” so it looks like this:




  

    
x.ByDefault.EveryControllerAction(d =>


    
   {


    
       d.Will<execute_the_result>();


    
       d.Will<access_the_database_through_a_unit_of_work>();


    
   });

  





The last thing we will do is open up HomeController and add this code above the Index action:




  

    
private IRepository _repository;


    
 


    
public HomeController(IRepository repository)


    
{


    
    _repository = repository;


    
}

  





I also modified the Index action to go ahead and create some database values before we query for them just so we can test this thing. (I only did this for the tutorial, I swear) So modify the Index action to look like this:




  

    
public IndexViewModel Index(IndexSetupViewModel inModel)


    
{


    
    var prod1 = new Product {Name = "TestProduct1", Description = "This is a test product"};


    
 


    
    _repository.Save(prod1);


    
 


    
    var prod2 = new Product {Name = "TestProduct2", Description = "This is a test product"};


    
 


    
    _repository.Save(prod2);


    
 


    
    var outModel = new IndexViewModel();


    
 


    
    var productList = _repository.Query<Product>();


    
 


    
    outModel.Products = productList.ToList().Select(x => new ProductDisplay(x));


    
 


    
    return outModel;


    
}

  





Now with you should be able to run your web app and browse to /home and all this will be executed and you will be on your way to creating a whole bunch of persist able objects for use with your FubuMVC app.



As always, feedback is welcome.
]]>
			http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/feed/
		9
		
		
		Book review: NHibernate in Action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/?utm_source=rss&utm_medium=rss&utm_campaign=book-review-nhibernate-in-action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/#comments
		Sat, 14 Jun 2008 20:42:15 +0000
		Jan Van Ryswyck
				
		
		

		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/
		
			kuate_cover150 Writing this book review feels kind of weird  because it hasn't actually hit the shelves yet. It is accessible however through the Manning Early Access Program. This book provides a clear insight of using NHibernate as the data access layer of your applications and beyond. 
 
The excessive amount of NHibernate features  isn't the only thing that is written down. There is also a good coverage of OO principles and Domain-Driven Design, although it isn't the primary objective of the book of course. This is especially true for the first and the last three chapters. If you've already read the nominal books DDD and you are familiar with Persistence Ignorance, then you can safely skim through these chapters unless you want to see the interpretation of the authors when it comes to these principles. If you are new to these concepts, then these chapters are of great value to wet your appetite.
 
Although this book covers a lot of ground, I would certainly recommend it when you're rather new to NHibernate and ORM's in general. I guess this still includes me, although I've been using NHibernate for quite some time now. If you already have some experience with NHibernate, then this book probably doesn't teach you that much. Still, it can quickly get you up to speed when you want to use a particular feature that you haven't used before. 
 
The only minor thing about this book is that I'm afraid that it will soon be out-of-date. The book only covers NHibernate 1.2.x and no features from the upcoming 2.0 release, which adds a lot of new and interesting features. It would be nice if the book already covered some of these features as most of them are ported from Hibernate itself, which is the original Java version.
 
On the other hand, this book provides an in-depth view of the basic features of NHibernate, which aren't necessarily going to change that much over time anyway.
 
Let me round off this post by saying that I'm really impressed by the list of books that Manning is going to release the next couple of months. These are the ones that I'm particularly interested in:
  
I already bought LINQ in Action and also read a lot of good things about C# in Depth, which I'm going to pick up soon.
 
Take care.
]]>
			http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/feed/
		7
		
		
		Integrating Castle Windsor and NHibernate with WCF
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/?utm_source=rss&utm_medium=rss&utm_campaign=integrating-castle-windsor-and-nhibernate-with-wcf
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/#comments
		Sun, 18 May 2008 14:08:20 +0000
		Jan Van Ryswyck
				
		

		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/
		
			Up until now, we were using the NHibernate facility of Castle Windsor for managing our NHibernate sessions in WCF. But, we want to have a session-per-request approach as one would use when integrating NHibernate with a regular web application. 
  
Yesterday I did a small spike to figure out how this should work. It turned out to be pretty easy. I used this excellent blog post written by Oran Dennison as my guide. 
  
First I created a class that implemented the IServiceBehavior interface.
  
   
public class DIServiceBehavior : IServiceBehavior
{
    private readonly ISessionFactory _sessionFactory;

    public DIServiceBehavior()
    {
        _sessionFactory = new Configuration()
            .Configure()
            .BuildSessionFactory();

        XmlConfigurator.Configure();    // Log4Net
    }

    public void ApplyDispatchBehavior(
             ServiceDescription serviceDescription, 
             ServiceHostBase serviceHostBase)
    {
        foreach(ChannelDispatcherBase cdb in 
                serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if(cd != null)
            {
                foreach(EndpointDispatcher ed in cd.Endpoints)
                {
                    ed.DispatchRuntime.InstanceProvider =
                        new DIInstanceProvider
                            (serviceDescription.ServiceType,
                              _sessionFactory);
                }
            }
        }
    }

    public void AddBindingParameters(
                ServiceDescription serviceDescription, 
                ServiceHostBase serviceHostBase,
                Collection<ServiceEndpoint> endpoints, 
                BindingParameterCollection bindingParameters) 
    { }
    
    public void Validate(ServiceDescription serviceDescription, 
                         ServiceHostBase serviceHostBase) 
    { }
}





The SessionFactory is created in the constructor because the ApplyDispatchBehaviour method can be called multiple times (for each endpoint). 



The next step is to create an instance provider by creating a class that implements the IInstanceProvider:




  
public class DIInstanceProvider : IInstanceProvider
{
    private const String NHibernateSessionKey = 
        "NHibernate.Session";

    private readonly Type _serviceType;
    private IDependencyContainer _dependencyContainer;
    private readonly ISessionFactory _sessionFactory;
    private ISession _session;

    public DIInstanceProvider(Type serviceType,
                               ISessionFactory sessionFactory)
    {
        Debug.Assert(null != serviceType, 
                     "null != serviceType");
        _serviceType = serviceType;

        Debug.Assert(null != sessionFactory, 
                     "null = sessionFactory");
        _sessionFactory = sessionFactory;
    }

    public Object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public Object GetInstance(InstanceContext instanceContext, 
                                Message message)
    {
        _dependencyContainer = new DependencyContainer();

        _session = _sessionFactory.OpenSession();
        _dependencyContainer
          .AddComponentInstance(NHibernateSessionKey, _session);

        return _dependencyContainer.Resolve(_serviceType);
    }

    public void ReleaseInstance(InstanceContext instanceContext, 
                                 Object instance)
    {
        if(null != _session)
        {
            _session.Close();
            _session = null;
        }

        if(null != _dependencyContainer)
        {
            _dependencyContainer.Dispose();
            _dependencyContainer = null;
        }
    }
}





I created a wrapper class around for Castle Windsor named DependencyContainer.  The GetInstance method opens a new session using the SessionFactory object we instantiated in the service behavior class. The session object is then registered with Castle Windsor. We can now implement our repositories like this:




  
public class SomeAggregateRepository
{
    private ISession _session;

    public SomeAggregateRepository(ISession session)
    {
        _session = session;
    }
    
    public SomeAggregate Get(Int64 id) 
    {
        return _session.Get<SomeAggregate>(id);
    }
}





When our service operation has been executed, the NHibernate is released by the ReleaseInstance method. Finishing our example, we need to implement a custom ServiceHost and a ServiceHostFactory:




  
public class DIServiceHost : ServiceHost
{
    public DependencyInjectionServiceHost() 
        : base() 
    { }
    
    public DIServiceHost(Type serviceType, 
                         params Uri[] baseAddresses) 
        : base(serviceType, baseAddresses) 
    { }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new DIServiceBehavior());
        base.OnOpening();
    }
}

public class DIServiceHostFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(
            Type serviceType, Uri[] baseAddresses)
    {
        return new DIServiceHost(serviceType, baseAddresses);
    }
}





The custom ServiceHostFactory class can now be used in the ServiceHost file required when doing IIS hosting:




  
<%@ ServiceHost Language="C#" 
                Debug="true" 
                Service="WindsorService.MyWindsorService" 
                Factory="WindsorService.DIServiceHostFactory"
                CodeBehind="MyWindsorService.svc.cs" %>





There is also another way for achieving this that I will be investigating the next week or so using the WCF Integration Facility for Castle Windsor. For some reason it is not available in the current release of the Castle stack so I have to grab it from the trunk. 



If you have any thoughts, improvements or suggestions I'm glad to hear them from you, my dear reader. It's the only way I'll ever learn :-). 



Till next time.
]]>
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		9
		
		
		Implementing NHibernate Interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/?utm_source=rss&utm_medium=rss&utm_campaign=implementing-nhibernate-interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/#comments
		Thu, 15 May 2008 18:29:26 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/
		
			One of the areas where NHibernate really shines is it's high extensibility features. The NHibernate API provides a massive amount of interfaces that can be implemented for your own custom extension pleasure. 
  
For me this is a nice change as opposed to the many sealed API's put out by the Redmond collective (WCF being the exception, the Entity Framework confirming the rule).
  
Anyhow, with great power comes great responsibility. Today I encountered a rather difficult problem with NHibernate that could have been easily prevented by reading the documentation (note to self: use the CTRL-Q shortcut of Resharper more often).
  
We have implemented an interceptor for automatically configuring audit information as described by this great post from Ray Houston. 
  
   
public class AuditInformationInterceptor 
    : EmptyInterceptor
{
    Boolean OnSave(Object entity, Object id, Object[] state, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }

    Boolean OnFlushDirty(Object entity, Object id, 
        Object[] currentState, Object[] previousState, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }                  
}





The mistake we made is that we manipulated the audit information of the entity directly in the OnSave and OnFlushDirty methods. This only became apparent when saving an aggregate root with his child entities. Everything worked fine until we wanted to persist one of the child entities that should have been a piece of cake but turned out to be the messenger of trouble. NHibernate refused to perform an INSERT statement, but instead threw an UPDATE statement at us. 



After some debugging we found out that the audit information should have been manipulated through the state and currentState arguments of the OnSave and OnFlushDirty methods respectively.



The documentation of the OnSave method clearly states:



The interceptor may modify the state, which will be used for the SQL INSERT

    
and propagated to the persistent object



Lesson relearned. 



I'm off, reading some docs. Until next time.
]]>
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		3
		
		
		On Persistence
		http://elegantcode.com/2008/05/01/on-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=on-persistence
		http://elegantcode.com/2008/05/01/on-persistence/#comments
		Thu, 01 May 2008 19:18:43 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/01/on-persistence/
		
			Earlier this week, I managed to convince our very wise decision makers to start using NHibernate for our persistence layer. My team mate on the project describes how it went. While I was reading Jeremy's train of thoughts, the following four lines made me realize we did the right thing:
  
Why are teams still writing persistence code by hand?  There's a bazillion persistence tools out there that all save development costs in some way over writing data access code by hand.  With very few exceptions, I'd say that at this point that if you're writing ADO.Net code or SQL by hand, you're stealing money from your employer.  
  
As another co-worker and NHibernate fan thoughtfully mentioned while congratulating us:
  
A small step for man, but a giant leap for mankind.
  
Few. What a week this turns out to be.
]]>
			http://elegantcode.com/2008/05/01/on-persistence/feed/
		2
		
		
		NHibernate 2.0 and Cascading Deletes
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-20-and-cascading-deletes-2
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/#comments
		Sat, 12 Apr 2008 18:58:12 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/
		
			The first alpha version of NHibernate 2.0 has been released some time ago. Oren has put a nice overview of the new features and the bugs that are solved for this first drop. In spite the fact that they put the word 'alpha' in the version name, it is actually RTM quality! 
  
One of the great new additions is the on-delete attribute of the key element for mapping collections:
  
<set name="Permissions" inverse="true" cascade="save-update">
  <key name="Authorization" on-delete="cascade"/>
  <one-to-many class="Permission"/>
</set>



This particular feature solves the issue I've had with one-shot deletes on inverse collections (which I described here). Configuring it this way ensures that NHibernate relies on database-level ON CASCADE DELETE foreign key constraints. This implies that when an object with a collection of child objects is deleted, a single DELETE  statement is used to remove all children at once instead of individual DELETE statements for each child object (which are called orphans at this point).



There are some things that you have to take into account here. First, this option bypasses NHibernate's optimistic locking strategy for versioned data. Second, make sure that you configure cascade="save-update" instead of cascade="all" to prevent NHibernate from performing delete cascade checks. This is important when lazy loading is enabled for the collection because it prevents that NHibernate loads one-to-many associations into memory. 



I'm really excited about this new release. Kudos to the men and women who have put so much effort in building such a wonderful ORM solution!



Till next time
]]>
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		0
		
		
		A New NHibernate Blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/?utm_source=rss&utm_medium=rss&utm_campaign=a-new-nhibernate-blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/#comments
		Tue, 01 Apr 2008 15:26:32 +0000
		Alex Mueller
				
		
		
		

		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/
		
			Craig Neuwirt recently started a blog focused on NHibernate, as mentioned by Ayende. NHibernate is an ORM tool I have used on current and past projects and it is something I feel I would like I want to study further. So far, Craig is walking us through NHibernate from the ground-up, with the latest and greatest. I anticipate this being an informative blog to follow.

The NHibernate FAQ
Craig Neuwirt
Hibernating Rhinos]]>
			http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/feed/
		2
		
		
		NHibernate IQuery to ISQLQuery Black Magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-iquery-to-isqlquery-black-magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/#comments
		Fri, 16 Nov 2007 06:12:55 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/
		
			posted on the forums and learned that: I'd run into a known bug / limitation.

Therefore I resorted to using ISQLQuery (yuk). I fixed several repository methods and then I ran into a very complicated IQuery. It was very painful to write the first time. In fact it was this experience that had caused me to change to using ICriteria as my default query method with specifications. I had a full suite of unit tests to protect me so I was confident that I could make the changes without breaking anything but I didn't want to do the conversion manually. Surely there was a trick?

It turns out that there is - NHibernate.Hql.Classic.QueryTranslator. The property that I needed is protected but thanks to a quick search of the forums I didn't even need to write my own reflection based method of calling it because someone had done it for me (thanks Nels). So what I did was take the HQL and convert it to SQL. I then did some string replacement to morph the SQL into what I needed. I am not proud of this but it was fast and it goes to show for flexible NHibernate is if you want to do some certifiable things.]]>
			http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/feed/
		0
		
		
		DTOs / Presentation Model and ICriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/?utm_source=rss&utm_medium=rss&utm_campaign=dtos-presentation-model-and-icriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/#comments
		Tue, 06 Nov 2007 06:11:41 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/
		
			NHibernate Projections I used HQL (IQuery) in the repository to define the query.

There are a some things that I don't like about HQL. For example the query is defined as a string. Strings are problematic because errors can't be detected at compile time. ICriteria queries go some way to alleviating this although they are certainly not perfect in this regard. You are writing tests against your repositories though aren't you?

But the reliance on strings is not the only problem with HQL. Today I needed to create a search screen. I wanted to use a variation of the technique that Ayende demonstrates here. With HQL the repository methods become ugly very quickly (and I mean wake up sweating at 2 am ugly). There is a mass of conditional string concatenation. And for each parameter I need to change 2 pieces of code (the code that builds the HQL and the code that binds the parameters).

So I decided to figure out how to use ICriteria to return a DTO. It transpires that the following code produces the same result as the HQL that I used before:

 



public List<InspectorDropDownDTO> GetAll()


{


 ICriteria q = session.CreateCriteria(typeof(Inspector), "i");


 q.CreateAlias("Person", "p");


 q.SetProjection(Projections.ProjectionList()


 .Add(Projections.Property("i.ID"), "InspectorID")


 .Add(Projections.Property("p.FirstName"), "FirstName")


 .Add(Projections.Property("p.LastName"), "LastName"));


 q.SetResultTransformer(Transformers.AliasToBean(typeof(InspectorDropDownDTO)));


 return q.List<InspectorDropDownDTO>();


}

It should be noted that the DTO itself is different with this method. A default constructor is now all that's needed because the AliasToBean transformer seems to work properly with ICriteria.

 



public class InspectorDropDownDTO


{


 private long _inspectorID;


 private string _firstName;


 private string _lastName;




 public long InspectorID { get { return _inspectorID; } set { _inspectorID = value; } }


 public string FirstName { get { return _firstName; } set { _firstName = value; } }


 public string LastName { get { return _lastName; } set { _lastName = value; } }


 public string FullName { get { return FirstName + " " + LastName; } }


}

Also note that you no longer need to import the DTO in an hbm.xml file.]]>
			http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/feed/
		2
		
		
		DTOs Simplify Complex Screens
		http://elegantcode.com/2008/05/01/on-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=on-persistence
		http://elegantcode.com/2008/05/01/on-persistence/#comments
		Thu, 01 May 2008 19:18:43 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/01/on-persistence/
		
			Earlier this week, I managed to convince our very wise decision makers to start using NHibernate for our persistence layer. My team mate on the project describes how it went. While I was reading Jeremy's train of thoughts, the following four lines made me realize we did the right thing:
  
Why are teams still writing persistence code by hand?  There's a bazillion persistence tools out there that all save development costs in some way over writing data access code by hand.  With very few exceptions, I'd say that at this point that if you're writing ADO.Net code or SQL by hand, you're stealing money from your employer.  
  
As another co-worker and NHibernate fan thoughtfully mentioned while congratulating us:
  
A small step for man, but a giant leap for mankind.
  
Few. What a week this turns out to be.
]]>
			http://elegantcode.com/2008/05/01/on-persistence/feed/
		2
		
		
		Elegant Code » NHibernate
	
	http://elegantcode.com
	
	Tue, 15 May 2012 10:00:00 +0000
	en
	hourly
	1
	http://wordpress.org/?v=3.3.1
		
		FubuMVC From Scratch – Part 4 Persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments
		Wed, 25 Mar 2009 21:22:00 +0000
		Ryan Kelley
				
		
		
		
		
		
		

		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/
		
			Previous posts in series:    
Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project
  
We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.
  
Class and Interfaces we have to implement: 
  
       
  • ISessionSourceConfiguration 
    •     
  • SQLServerSessionSourceConfiguration 
    •     
  • IUnitOfWork 
    •     
  • INHibernateUnitOfWork 
    •     
  • NHibernateUnitOfWork 
    •     
  • IRepository 
    •     
  • NHibernateRepository 
    •     
  • DomainEntity 
    •     
  • IDomainQuery 
    •     
  • FubuSamplePersistenceModel 
    •  
  
Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence
  
Before we start you probably want to go ahead and add the following references to your core project and Web project
  
FubuMVC-Persist-Ref 
  
Let’s just work our way down the list and get these files implemented. 
  
ISessionSourceConfiguration
  
   
     
public interface ISessionSourceConfiguration


    
{


    
    bool IsNewDatabase { get; }


    
    ISessionSource CreateSessionSource(PersistenceModel model);


    
}

  





SQLServerSessionSourceConfiguration




  

    
public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration


    
{


    
    #region Implementation of ISessionSourceConfiguration


    
 


    
    public bool IsNewDatabase


    
    {


    
        get { return false; }


    
    }


    
 


    
    public ISessionSource CreateSessionSource(PersistenceModel model)


    
    {


    
        var properties = GetProperties();


    
        var source = new SessionSource(properties, model);


    
 


    
        create_schema_if_it_does_not_already_exist(source);


    
 


    
        return source;


    
    }


    
 


    
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)


    
    {


    
        if (IsNewDatabase) source.BuildSchema();


    
    }


    
 


    
    protected IDictionary<string, string> GetProperties()


    
    {


    
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;


    
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);


    
        config.ShowSql();


    
        config.UseOuterJoin();


    
 


    
        return config.ToProperties();


    
    }


    
    #endregion


    
}

  





A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.



IUnitOfWork




  

    
public interface IUnitOfWork : IDisposable


    
{


    
    void Initialize();


    
    void Commit();


    
    void Rollback();


    
}

  





INHibernateUnitOfWork




  

    
public interface INHibernateUnitOfWork : IUnitOfWork


    
{


    
    ISession CurrentSession { get; }


    
}

  





NHibernateUnitOfWork




  

    
public class NHibernateUnitOfWork : INHibernateUnitOfWork


    
{


    
    private ITransaction _transaction;


    
    private bool _isDisposed;


    
    private readonly ISessionSource _source;


    
    private bool _isInitialized;


    
 


    
    public NHibernateUnitOfWork(ISessionSource source)


    
    {


    
        _source = source;


    
    }


    
 


    
    public void Initialize()


    
    {


    
        should_not_currently_be_disposed();


    
 


    
        CurrentSession = _source.CreateSession();


    
        begin_new_transaction();


    
 


    
        _isInitialized = true;


    
    }


    
 


    
    public ISession CurrentSession { get; private set; }


    
 


    
    public void Commit()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Commit();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void begin_new_transaction()


    
    {


    
        if (_transaction != null)


    
        {


    
            _transaction.Dispose();


    
        }


    
 


    
        _transaction = CurrentSession.BeginTransaction();


    
    }


    
 


    
    public void Rollback()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Rollback();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void should_not_currently_be_disposed()


    
    {


    
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);


    
    }


    
 


    
    private void should_be_initialized_first()


    
    {


    
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");


    
    }


    
 


    
    public void Dispose()


    
    {


    
        if (_isDisposed || !_isInitialized) return;


    
 


    
        _transaction.Dispose();


    
        CurrentSession.Dispose();


    
 


    
        _isDisposed = true;


    
    }


    
}

  





IRepository




  

    
public interface IRepository


    
{


    
    void Save<ENTITY>(ENTITY entity)


    
        where ENTITY : DomainEntity;


    
 


    
    ENTITY Load<ENTITY>(Guid id)


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>()


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)


    
        where ENTITY : DomainEntity;


    
 


    
    void Delete<ENTITY>(ENTITY entity);


    
 


    
    void DeleteAll<ENTITY>();


    
}

  





NHibernateRepository




  

    
public class NHibernateRepository : IRepository


    
{


    
    private readonly INHibernateUnitOfWork _unitOfWork;


    
 


    
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity


    
    {


    
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);


    
    }


    
 


    
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>();


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);


    
    }


    
 


    
    public void Delete<ENTITY>(ENTITY entity)


    
    {


    
        _unitOfWork.CurrentSession.Delete(entity);   


    
    }


    
 


    
    public void DeleteAll<ENTITY>()


    
    {


    
        var query = String.Format("from {0}", typeof(ENTITY).Name);


    
        _unitOfWork.CurrentSession.Delete(query);   


    
    }


    
}

  





DomainEntity



Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository




  

    
public class DomainEntity : IEquatable<DomainEntity>


    
{


    
    public virtual Guid ID { get; set; }


    
 


    
    public virtual bool Equals(DomainEntity other)


    
    {


    
        if (ReferenceEquals(null, other)) return false;


    
        if (ReferenceEquals(this, other)) return true;


    
        return other.ID.Equals(ID);


    
    }


    
 


    
    public override bool Equals(object obj)


    
    {


    
        if (ReferenceEquals(null, obj)) return false;


    
        if (ReferenceEquals(this, obj)) return true;


    
        if (obj.GetType() != GetType()) return false;


    
        return Equals((DomainEntity)obj);


    
    }


    
 


    
    public override int GetHashCode()


    
    {


    
        return ID.GetHashCode();


    
    }


    
 


    
    public static bool operator ==(DomainEntity left, DomainEntity right)


    
    {


    
        return Equals(left, right);


    
    }


    
 


    
    public static bool operator !=(DomainEntity left, DomainEntity right)


    
    {


    
        return !Equals(left, right);


    
    }


    
}

  





IDomainQuery




  

    
public interface IDomainQuery<ENTITY>


    
    where ENTITY : DomainEntity


    
{


    
    Expression<Func<ENTITY, bool>> Expression { get; }


    
}

  





FubuSamplePersistenceModel




  

    
namespace FubuSample.Core.Domain.Persistence


    
{


    
    public class FubuSamplePersistenceModel : PersistenceModel


    
    {


    
        public FubuSamplePersistenceModel()


    
        {


    
            addMappingsFromThisAssembly();


    
        }


    
    }


    
}

  





Now that we have all the puzzle pieces in place we need to hook them up and make them do some work. Open up FubuSampleWebRegistry 



And add the following code:




  

    
protected override void configure()


    
{


    
    ForRequestedType<ISessionSourceConfiguration>().AsSingletons()


    
        .TheDefault.Is.OfConcreteType<SQLServerSessionSourceConfiguration>();


    
 


    
 


    
    ForRequestedType<ISessionSource>().AsSingletons()


    
        .TheDefault.Is.ConstructedBy(ctx =>


    
                                     ctx.GetInstance<ISessionSourceConfiguration>()


    
                                         .CreateSessionSource(new FubuSamplePersistenceModel()));


    
 


    
    ForRequestedType<IUnitOfWork>().TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<INHibernateUnitOfWork>());


    
 


    
    ForRequestedType<INHibernateUnitOfWork>().CacheBy(InstanceScope.Hybrid)


    
        .TheDefault.Is.OfConcreteType<NHibernateUnitOfWork>();


    
 


    
    ForRequestedType<IRepository>().TheDefault.Is.OfConcreteType<NHibernateRepository>();


    
}

  





With a little luck and all of our mad skills, we should be able to talk to the database now. So we need to plumb our simple product object up to talk to NHibernate. We will do this with a mapping file, and since we are using FluentNHibernate we can do this strongly typed.



Make the following modifications to Product: Extend DomainEntity and get rid of Id Property, it is inherited




  

    
public class Product : DomainEntity


    
{


    
    public virtual string Name { get; set; }


    
    public virtual string Description { get; set; }


    
}

  





Add mapping file for Product:




  

    
namespace FubuSample.Core.Domain.Mapping


    
{


    
    public class ProductMap : ClassMap<Product>


    
    {


    
        public ProductMap()


    
        {


    
            Id(e => e.ID).GeneratedBy.GuidComb();


    
 


    
            Map(p => p.Name);


    
            Map(p => p.Description);


    
            


    
        }


    
    }


    
}

  





You may also want to setup your connection string at this point in the Web.Config file, mine looks like this:




  

    
<add name="MYDBKEY" connectionString="Data Source=LOCALHOST;initial catalog=FubuSample;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />

  





I also created an empty database in my local SQL Server instance called “FubuSample” And then I went back to SQLServerSessionSourceConfiguration and changed the value of IsNewDatabase to return true. This will create the schema for the database when the application first runs. There is a multitude of different ways that we can handle this, but this was easy for the tutorial purposes.



Next we will add a behavior to our core project and tell FubuMVC to apply that behavior to all or our ControllerActions.



Create a class named “access_the_database_through_a_unit_of_work” in your Core.Web.Behaviors namespace. The contents will look like this:




  

    
public class access_the_database_through_a_unit_of_work : IControllerActionBehavior


    
{


    
    private readonly IUnitOfWork _unitOfWork;


    
 


    
    public access_the_database_through_a_unit_of_work(IUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public IControllerActionBehavior InsideBehavior { get; set; }


    
    public IInvocationResult Result { get; set; }


    
 


    
    public OUTPUT Invoke<INPUT, OUTPUT>(INPUT input, Func<INPUT, OUTPUT> func)


    
        where INPUT : class


    
        where OUTPUT : class


    
    {


    
        _unitOfWork.Initialize();


    
 


    
        try


    
        {


    
            var output = InsideBehavior.Invoke(input, func);


    
            Result = InsideBehavior.Result;


    
 


    
            _unitOfWork.Commit();


    
 


    
            return output;


    
        }


    
        catch


    
        {


    
            _unitOfWork.Rollback();


    
            throw;


    
        }


    
        finally


    
        {


    
            _unitOfWork.Dispose();


    
        }


    
    }


    
}

  





Now to tell FubuMVC what to do, open up Global.asax.cs or your Bootstrapper, wherever you are doing the configuration of FubuMVC. In this project we are doing it in Global.asax.cs Add a new behavior to the section that starts with “x.ByDefault.EveryControllerAction” so it looks like this:




  

    
x.ByDefault.EveryControllerAction(d =>


    
   {


    
       d.Will<execute_the_result>();


    
       d.Will<access_the_database_through_a_unit_of_work>();


    
   });

  





The last thing we will do is open up HomeController and add this code above the Index action:




  

    
private IRepository _repository;


    
 


    
public HomeController(IRepository repository)


    
{


    
    _repository = repository;


    
}

  





I also modified the Index action to go ahead and create some database values before we query for them just so we can test this thing. (I only did this for the tutorial, I swear) So modify the Index action to look like this:




  

    
public IndexViewModel Index(IndexSetupViewModel inModel)


    
{


    
    var prod1 = new Product {Name = "TestProduct1", Description = "This is a test product"};


    
 


    
    _repository.Save(prod1);


    
 


    
    var prod2 = new Product {Name = "TestProduct2", Description = "This is a test product"};


    
 


    
    _repository.Save(prod2);


    
 


    
    var outModel = new IndexViewModel();


    
 


    
    var productList = _repository.Query<Product>();


    
 


    
    outModel.Products = productList.ToList().Select(x => new ProductDisplay(x));


    
 


    
    return outModel;


    
}

  





Now with you should be able to run your web app and browse to /home and all this will be executed and you will be on your way to creating a whole bunch of persist able objects for use with your FubuMVC app.



As always, feedback is welcome.
]]>
			http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/feed/
		9
		
		
		Book review: NHibernate in Action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/?utm_source=rss&utm_medium=rss&utm_campaign=book-review-nhibernate-in-action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/#comments
		Sat, 14 Jun 2008 20:42:15 +0000
		Jan Van Ryswyck
				
		
		

		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/
		
			kuate_cover150 Writing this book review feels kind of weird  because it hasn't actually hit the shelves yet. It is accessible however through the Manning Early Access Program. This book provides a clear insight of using NHibernate as the data access layer of your applications and beyond. 
 
The excessive amount of NHibernate features  isn't the only thing that is written down. There is also a good coverage of OO principles and Domain-Driven Design, although it isn't the primary objective of the book of course. This is especially true for the first and the last three chapters. If you've already read the nominal books DDD and you are familiar with Persistence Ignorance, then you can safely skim through these chapters unless you want to see the interpretation of the authors when it comes to these principles. If you are new to these concepts, then these chapters are of great value to wet your appetite.
 
Although this book covers a lot of ground, I would certainly recommend it when you're rather new to NHibernate and ORM's in general. I guess this still includes me, although I've been using NHibernate for quite some time now. If you already have some experience with NHibernate, then this book probably doesn't teach you that much. Still, it can quickly get you up to speed when you want to use a particular feature that you haven't used before. 
 
The only minor thing about this book is that I'm afraid that it will soon be out-of-date. The book only covers NHibernate 1.2.x and no features from the upcoming 2.0 release, which adds a lot of new and interesting features. It would be nice if the book already covered some of these features as most of them are ported from Hibernate itself, which is the original Java version.
 
On the other hand, this book provides an in-depth view of the basic features of NHibernate, which aren't necessarily going to change that much over time anyway.
 
Let me round off this post by saying that I'm really impressed by the list of books that Manning is going to release the next couple of months. These are the ones that I'm particularly interested in:
  
I already bought LINQ in Action and also read a lot of good things about C# in Depth, which I'm going to pick up soon.
 
Take care.
]]>
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		7
		
		
		Integrating Castle Windsor and NHibernate with WCF
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/?utm_source=rss&utm_medium=rss&utm_campaign=integrating-castle-windsor-and-nhibernate-with-wcf
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/#comments
		Sun, 18 May 2008 14:08:20 +0000
		Jan Van Ryswyck
				
		

		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/
		
			Up until now, we were using the NHibernate facility of Castle Windsor for managing our NHibernate sessions in WCF. But, we want to have a session-per-request approach as one would use when integrating NHibernate with a regular web application. 
  
Yesterday I did a small spike to figure out how this should work. It turned out to be pretty easy. I used this excellent blog post written by Oran Dennison as my guide. 
  
First I created a class that implemented the IServiceBehavior interface.
  
   
public class DIServiceBehavior : IServiceBehavior
{
    private readonly ISessionFactory _sessionFactory;

    public DIServiceBehavior()
    {
        _sessionFactory = new Configuration()
            .Configure()
            .BuildSessionFactory();

        XmlConfigurator.Configure();    // Log4Net
    }

    public void ApplyDispatchBehavior(
             ServiceDescription serviceDescription, 
             ServiceHostBase serviceHostBase)
    {
        foreach(ChannelDispatcherBase cdb in 
                serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if(cd != null)
            {
                foreach(EndpointDispatcher ed in cd.Endpoints)
                {
                    ed.DispatchRuntime.InstanceProvider =
                        new DIInstanceProvider
                            (serviceDescription.ServiceType,
                              _sessionFactory);
                }
            }
        }
    }

    public void AddBindingParameters(
                ServiceDescription serviceDescription, 
                ServiceHostBase serviceHostBase,
                Collection<ServiceEndpoint> endpoints, 
                BindingParameterCollection bindingParameters) 
    { }
    
    public void Validate(ServiceDescription serviceDescription, 
                         ServiceHostBase serviceHostBase) 
    { }
}





The SessionFactory is created in the constructor because the ApplyDispatchBehaviour method can be called multiple times (for each endpoint). 



The next step is to create an instance provider by creating a class that implements the IInstanceProvider:




  
public class DIInstanceProvider : IInstanceProvider
{
    private const String NHibernateSessionKey = 
        "NHibernate.Session";

    private readonly Type _serviceType;
    private IDependencyContainer _dependencyContainer;
    private readonly ISessionFactory _sessionFactory;
    private ISession _session;

    public DIInstanceProvider(Type serviceType,
                               ISessionFactory sessionFactory)
    {
        Debug.Assert(null != serviceType, 
                     "null != serviceType");
        _serviceType = serviceType;

        Debug.Assert(null != sessionFactory, 
                     "null = sessionFactory");
        _sessionFactory = sessionFactory;
    }

    public Object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public Object GetInstance(InstanceContext instanceContext, 
                                Message message)
    {
        _dependencyContainer = new DependencyContainer();

        _session = _sessionFactory.OpenSession();
        _dependencyContainer
          .AddComponentInstance(NHibernateSessionKey, _session);

        return _dependencyContainer.Resolve(_serviceType);
    }

    public void ReleaseInstance(InstanceContext instanceContext, 
                                 Object instance)
    {
        if(null != _session)
        {
            _session.Close();
            _session = null;
        }

        if(null != _dependencyContainer)
        {
            _dependencyContainer.Dispose();
            _dependencyContainer = null;
        }
    }
}





I created a wrapper class around for Castle Windsor named DependencyContainer.  The GetInstance method opens a new session using the SessionFactory object we instantiated in the service behavior class. The session object is then registered with Castle Windsor. We can now implement our repositories like this:




  
public class SomeAggregateRepository
{
    private ISession _session;

    public SomeAggregateRepository(ISession session)
    {
        _session = session;
    }
    
    public SomeAggregate Get(Int64 id) 
    {
        return _session.Get<SomeAggregate>(id);
    }
}





When our service operation has been executed, the NHibernate is released by the ReleaseInstance method. Finishing our example, we need to implement a custom ServiceHost and a ServiceHostFactory:




  
public class DIServiceHost : ServiceHost
{
    public DependencyInjectionServiceHost() 
        : base() 
    { }
    
    public DIServiceHost(Type serviceType, 
                         params Uri[] baseAddresses) 
        : base(serviceType, baseAddresses) 
    { }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new DIServiceBehavior());
        base.OnOpening();
    }
}

public class DIServiceHostFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(
            Type serviceType, Uri[] baseAddresses)
    {
        return new DIServiceHost(serviceType, baseAddresses);
    }
}





The custom ServiceHostFactory class can now be used in the ServiceHost file required when doing IIS hosting:




  
<%@ ServiceHost Language="C#" 
                Debug="true" 
                Service="WindsorService.MyWindsorService" 
                Factory="WindsorService.DIServiceHostFactory"
                CodeBehind="MyWindsorService.svc.cs" %>





There is also another way for achieving this that I will be investigating the next week or so using the WCF Integration Facility for Castle Windsor. For some reason it is not available in the current release of the Castle stack so I have to grab it from the trunk. 



If you have any thoughts, improvements or suggestions I'm glad to hear them from you, my dear reader. It's the only way I'll ever learn :-). 



Till next time.
]]>
			http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/feed/
		9
		
		
		Implementing NHibernate Interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/?utm_source=rss&utm_medium=rss&utm_campaign=implementing-nhibernate-interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/#comments
		Thu, 15 May 2008 18:29:26 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/
		
			One of the areas where NHibernate really shines is it's high extensibility features. The NHibernate API provides a massive amount of interfaces that can be implemented for your own custom extension pleasure. 
  
For me this is a nice change as opposed to the many sealed API's put out by the Redmond collective (WCF being the exception, the Entity Framework confirming the rule).
  
Anyhow, with great power comes great responsibility. Today I encountered a rather difficult problem with NHibernate that could have been easily prevented by reading the documentation (note to self: use the CTRL-Q shortcut of Resharper more often).
  
We have implemented an interceptor for automatically configuring audit information as described by this great post from Ray Houston. 
  
   
public class AuditInformationInterceptor 
    : EmptyInterceptor
{
    Boolean OnSave(Object entity, Object id, Object[] state, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }

    Boolean OnFlushDirty(Object entity, Object id, 
        Object[] currentState, Object[] previousState, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }                  
}





The mistake we made is that we manipulated the audit information of the entity directly in the OnSave and OnFlushDirty methods. This only became apparent when saving an aggregate root with his child entities. Everything worked fine until we wanted to persist one of the child entities that should have been a piece of cake but turned out to be the messenger of trouble. NHibernate refused to perform an INSERT statement, but instead threw an UPDATE statement at us. 



After some debugging we found out that the audit information should have been manipulated through the state and currentState arguments of the OnSave and OnFlushDirty methods respectively.



The documentation of the OnSave method clearly states:



The interceptor may modify the state, which will be used for the SQL INSERT

    
and propagated to the persistent object



Lesson relearned. 



I'm off, reading some docs. Until next time.
]]>
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		3
		
		
		On Persistence
		http://elegantcode.com/2008/05/01/on-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=on-persistence
		http://elegantcode.com/2008/05/01/on-persistence/#comments
		Thu, 01 May 2008 19:18:43 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/01/on-persistence/
		
			Earlier this week, I managed to convince our very wise decision makers to start using NHibernate for our persistence layer. My team mate on the project describes how it went. While I was reading Jeremy's train of thoughts, the following four lines made me realize we did the right thing:
  
Why are teams still writing persistence code by hand?  There's a bazillion persistence tools out there that all save development costs in some way over writing data access code by hand.  With very few exceptions, I'd say that at this point that if you're writing ADO.Net code or SQL by hand, you're stealing money from your employer.  
  
As another co-worker and NHibernate fan thoughtfully mentioned while congratulating us:
  
A small step for man, but a giant leap for mankind.
  
Few. What a week this turns out to be.
]]>
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		2
		
		
		NHibernate 2.0 and Cascading Deletes
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-20-and-cascading-deletes-2
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/#comments
		Sat, 12 Apr 2008 18:58:12 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/
		
			The first alpha version of NHibernate 2.0 has been released some time ago. Oren has put a nice overview of the new features and the bugs that are solved for this first drop. In spite the fact that they put the word 'alpha' in the version name, it is actually RTM quality! 
  
One of the great new additions is the on-delete attribute of the key element for mapping collections:
  
<set name="Permissions" inverse="true" cascade="save-update">
  <key name="Authorization" on-delete="cascade"/>
  <one-to-many class="Permission"/>
</set>



This particular feature solves the issue I've had with one-shot deletes on inverse collections (which I described here). Configuring it this way ensures that NHibernate relies on database-level ON CASCADE DELETE foreign key constraints. This implies that when an object with a collection of child objects is deleted, a single DELETE  statement is used to remove all children at once instead of individual DELETE statements for each child object (which are called orphans at this point).



There are some things that you have to take into account here. First, this option bypasses NHibernate's optimistic locking strategy for versioned data. Second, make sure that you configure cascade="save-update" instead of cascade="all" to prevent NHibernate from performing delete cascade checks. This is important when lazy loading is enabled for the collection because it prevents that NHibernate loads one-to-many associations into memory. 



I'm really excited about this new release. Kudos to the men and women who have put so much effort in building such a wonderful ORM solution!



Till next time
]]>
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		0
		
		
		A New NHibernate Blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/?utm_source=rss&utm_medium=rss&utm_campaign=a-new-nhibernate-blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/#comments
		Tue, 01 Apr 2008 15:26:32 +0000
		Alex Mueller
				
		
		
		

		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/
		
			Craig Neuwirt recently started a blog focused on NHibernate, as mentioned by Ayende. NHibernate is an ORM tool I have used on current and past projects and it is something I feel I would like I want to study further. So far, Craig is walking us through NHibernate from the ground-up, with the latest and greatest. I anticipate this being an informative blog to follow.

The NHibernate FAQ
Craig Neuwirt
Hibernating Rhinos]]>
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		2
		
		
		NHibernate IQuery to ISQLQuery Black Magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-iquery-to-isqlquery-black-magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/#comments
		Fri, 16 Nov 2007 06:12:55 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/
		
			posted on the forums and learned that: I'd run into a known bug / limitation.

Therefore I resorted to using ISQLQuery (yuk). I fixed several repository methods and then I ran into a very complicated IQuery. It was very painful to write the first time. In fact it was this experience that had caused me to change to using ICriteria as my default query method with specifications. I had a full suite of unit tests to protect me so I was confident that I could make the changes without breaking anything but I didn't want to do the conversion manually. Surely there was a trick?

It turns out that there is - NHibernate.Hql.Classic.QueryTranslator. The property that I needed is protected but thanks to a quick search of the forums I didn't even need to write my own reflection based method of calling it because someone had done it for me (thanks Nels). So what I did was take the HQL and convert it to SQL. I then did some string replacement to morph the SQL into what I needed. I am not proud of this but it was fast and it goes to show for flexible NHibernate is if you want to do some certifiable things.]]>
			http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/feed/
		0
		
		
		DTOs / Presentation Model and ICriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/?utm_source=rss&utm_medium=rss&utm_campaign=dtos-presentation-model-and-icriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/#comments
		Tue, 06 Nov 2007 06:11:41 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/
		
			NHibernate Projections I used HQL (IQuery) in the repository to define the query.

There are a some things that I don't like about HQL. For example the query is defined as a string. Strings are problematic because errors can't be detected at compile time. ICriteria queries go some way to alleviating this although they are certainly not perfect in this regard. You are writing tests against your repositories though aren't you?

But the reliance on strings is not the only problem with HQL. Today I needed to create a search screen. I wanted to use a variation of the technique that Ayende demonstrates here. With HQL the repository methods become ugly very quickly (and I mean wake up sweating at 2 am ugly). There is a mass of conditional string concatenation. And for each parameter I need to change 2 pieces of code (the code that builds the HQL and the code that binds the parameters).

So I decided to figure out how to use ICriteria to return a DTO. It transpires that the following code produces the same result as the HQL that I used before:

 



public List<InspectorDropDownDTO> GetAll()


{


 ICriteria q = session.CreateCriteria(typeof(Inspector), "i");


 q.CreateAlias("Person", "p");


 q.SetProjection(Projections.ProjectionList()


 .Add(Projections.Property("i.ID"), "InspectorID")


 .Add(Projections.Property("p.FirstName"), "FirstName")


 .Add(Projections.Property("p.LastName"), "LastName"));


 q.SetResultTransformer(Transformers.AliasToBean(typeof(InspectorDropDownDTO)));


 return q.List<InspectorDropDownDTO>();


}

It should be noted that the DTO itself is different with this method. A default constructor is now all that's needed because the AliasToBean transformer seems to work properly with ICriteria.

 



public class InspectorDropDownDTO


{


 private long _inspectorID;


 private string _firstName;


 private string _lastName;




 public long InspectorID { get { return _inspectorID; } set { _inspectorID = value; } }


 public string FirstName { get { return _firstName; } set { _firstName = value; } }


 public string LastName { get { return _lastName; } set { _lastName = value; } }


 public string FullName { get { return FirstName + " " + LastName; } }


}

Also note that you no longer need to import the DTO in an hbm.xml file.]]>
			http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/feed/
		2
		
		
		DTOs Simplify Complex Screens
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-20-and-cascading-deletes-2
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/#comments
		Sat, 12 Apr 2008 18:58:12 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/
		
			The first alpha version of NHibernate 2.0 has been released some time ago. Oren has put a nice overview of the new features and the bugs that are solved for this first drop. In spite the fact that they put the word 'alpha' in the version name, it is actually RTM quality! 
  
One of the great new additions is the on-delete attribute of the key element for mapping collections:
  
<set name="Permissions" inverse="true" cascade="save-update">
  <key name="Authorization" on-delete="cascade"/>
  <one-to-many class="Permission"/>
</set>



This particular feature solves the issue I've had with one-shot deletes on inverse collections (which I described here). Configuring it this way ensures that NHibernate relies on database-level ON CASCADE DELETE foreign key constraints. This implies that when an object with a collection of child objects is deleted, a single DELETE  statement is used to remove all children at once instead of individual DELETE statements for each child object (which are called orphans at this point).



There are some things that you have to take into account here. First, this option bypasses NHibernate's optimistic locking strategy for versioned data. Second, make sure that you configure cascade="save-update" instead of cascade="all" to prevent NHibernate from performing delete cascade checks. This is important when lazy loading is enabled for the collection because it prevents that NHibernate loads one-to-many associations into memory. 



I'm really excited about this new release. Kudos to the men and women who have put so much effort in building such a wonderful ORM solution!



Till next time
]]>
			http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/feed/
		0
		
		
		Elegant Code » NHibernate
	
	http://elegantcode.com
	
	Tue, 15 May 2012 10:00:00 +0000
	en
	hourly
	1
	http://wordpress.org/?v=3.3.1
		
		FubuMVC From Scratch – Part 4 Persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments
		Wed, 25 Mar 2009 21:22:00 +0000
		Ryan Kelley
				
		
		
		
		
		
		

		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/
		
			Previous posts in series:    
Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project
  
We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.
  
Class and Interfaces we have to implement: 
  
       
  • ISessionSourceConfiguration 
    •     
  • SQLServerSessionSourceConfiguration 
    •     
  • IUnitOfWork 
    •     
  • INHibernateUnitOfWork 
    •     
  • NHibernateUnitOfWork 
    •     
  • IRepository 
    •     
  • NHibernateRepository 
    •     
  • DomainEntity 
    •     
  • IDomainQuery 
    •     
  • FubuSamplePersistenceModel 
    •  
  
Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence
  
Before we start you probably want to go ahead and add the following references to your core project and Web project
  
FubuMVC-Persist-Ref 
  
Let’s just work our way down the list and get these files implemented. 
  
ISessionSourceConfiguration
  
   
     
public interface ISessionSourceConfiguration


    
{


    
    bool IsNewDatabase { get; }


    
    ISessionSource CreateSessionSource(PersistenceModel model);


    
}

  





SQLServerSessionSourceConfiguration




  

    
public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration


    
{


    
    #region Implementation of ISessionSourceConfiguration


    
 


    
    public bool IsNewDatabase


    
    {


    
        get { return false; }


    
    }


    
 


    
    public ISessionSource CreateSessionSource(PersistenceModel model)


    
    {


    
        var properties = GetProperties();


    
        var source = new SessionSource(properties, model);


    
 


    
        create_schema_if_it_does_not_already_exist(source);


    
 


    
        return source;


    
    }


    
 


    
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)


    
    {


    
        if (IsNewDatabase) source.BuildSchema();


    
    }


    
 


    
    protected IDictionary<string, string> GetProperties()


    
    {


    
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;


    
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);


    
        config.ShowSql();


    
        config.UseOuterJoin();


    
 


    
        return config.ToProperties();


    
    }


    
    #endregion


    
}

  





A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.



IUnitOfWork




  

    
public interface IUnitOfWork : IDisposable


    
{


    
    void Initialize();


    
    void Commit();


    
    void Rollback();


    
}

  





INHibernateUnitOfWork




  

    
public interface INHibernateUnitOfWork : IUnitOfWork


    
{


    
    ISession CurrentSession { get; }


    
}

  





NHibernateUnitOfWork




  

    
public class NHibernateUnitOfWork : INHibernateUnitOfWork


    
{


    
    private ITransaction _transaction;


    
    private bool _isDisposed;


    
    private readonly ISessionSource _source;


    
    private bool _isInitialized;


    
 


    
    public NHibernateUnitOfWork(ISessionSource source)


    
    {


    
        _source = source;


    
    }


    
 


    
    public void Initialize()


    
    {


    
        should_not_currently_be_disposed();


    
 


    
        CurrentSession = _source.CreateSession();


    
        begin_new_transaction();


    
 


    
        _isInitialized = true;


    
    }


    
 


    
    public ISession CurrentSession { get; private set; }


    
 


    
    public void Commit()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Commit();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void begin_new_transaction()


    
    {


    
        if (_transaction != null)


    
        {


    
            _transaction.Dispose();


    
        }


    
 


    
        _transaction = CurrentSession.BeginTransaction();


    
    }


    
 


    
    public void Rollback()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Rollback();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void should_not_currently_be_disposed()


    
    {


    
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);


    
    }


    
 


    
    private void should_be_initialized_first()


    
    {


    
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");


    
    }


    
 


    
    public void Dispose()


    
    {


    
        if (_isDisposed || !_isInitialized) return;


    
 


    
        _transaction.Dispose();


    
        CurrentSession.Dispose();


    
 


    
        _isDisposed = true;


    
    }


    
}

  





IRepository




  

    
public interface IRepository


    
{


    
    void Save<ENTITY>(ENTITY entity)


    
        where ENTITY : DomainEntity;


    
 


    
    ENTITY Load<ENTITY>(Guid id)


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>()


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)


    
        where ENTITY : DomainEntity;


    
 


    
    void Delete<ENTITY>(ENTITY entity);


    
 


    
    void DeleteAll<ENTITY>();


    
}

  





NHibernateRepository




  

    
public class NHibernateRepository : IRepository


    
{


    
    private readonly INHibernateUnitOfWork _unitOfWork;


    
 


    
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity


    
    {


    
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);


    
    }


    
 


    
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>();


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);


    
    }


    
 


    
    public void Delete<ENTITY>(ENTITY entity)


    
    {


    
        _unitOfWork.CurrentSession.Delete(entity);   


    
    }


    
 


    
    public void DeleteAll<ENTITY>()


    
    {


    
        var query = String.Format("from {0}", typeof(ENTITY).Name);


    
        _unitOfWork.CurrentSession.Delete(query);   


    
    }


    
}

  





DomainEntity



Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository




  

    
public class DomainEntity : IEquatable<DomainEntity>


    
{


    
    public virtual Guid ID { get; set; }


    
 


    
    public virtual bool Equals(DomainEntity other)


    
    {


    
        if (ReferenceEquals(null, other)) return false;


    
        if (ReferenceEquals(this, other)) return true;


    
        return other.ID.Equals(ID);


    
    }


    
 


    
    public override bool Equals(object obj)


    
    {


    
        if (ReferenceEquals(null, obj)) return false;


    
        if (ReferenceEquals(this, obj)) return true;


    
        if (obj.GetType() != GetType()) return false;


    
        return Equals((DomainEntity)obj);


    
    }


    
 


    
    public override int GetHashCode()


    
    {


    
        return ID.GetHashCode();


    
    }


    
 


    
    public static bool operator ==(DomainEntity left, DomainEntity right)


    
    {


    
        return Equals(left, right);


    
    }


    
 


    
    public static bool operator !=(DomainEntity left, DomainEntity right)


    
    {


    
        return !Equals(left, right);


    
    }


    
}

  





IDomainQuery




  

    
public interface IDomainQuery<ENTITY>


    
    where ENTITY : DomainEntity


    
{


    
    Expression<Func<ENTITY, bool>> Expression { get; }


    
}

  





FubuSamplePersistenceModel




  

    
namespace FubuSample.Core.Domain.Persistence


    
{


    
    public class FubuSamplePersistenceModel : PersistenceModel


    
    {


    
        public FubuSamplePersistenceModel()


    
        {


    
            addMappingsFromThisAssembly();


    
        }


    
    }


    
}

  





Now that we have all the puzzle pieces in place we need to hook them up and make them do some work. Open up FubuSampleWebRegistry 



And add the following code:




  

    
protected override void configure()


    
{


    
    ForRequestedType<ISessionSourceConfiguration>().AsSingletons()


    
        .TheDefault.Is.OfConcreteType<SQLServerSessionSourceConfiguration>();


    
 


    
 


    
    ForRequestedType<ISessionSource>().AsSingletons()


    
        .TheDefault.Is.ConstructedBy(ctx =>


    
                                     ctx.GetInstance<ISessionSourceConfiguration>()


    
                                         .CreateSessionSource(new FubuSamplePersistenceModel()));


    
 


    
    ForRequestedType<IUnitOfWork>().TheDefault.Is.ConstructedBy(ctx => ctx.GetInstance<INHibernateUnitOfWork>());


    
 


    
    ForRequestedType<INHibernateUnitOfWork>().CacheBy(InstanceScope.Hybrid)


    
        .TheDefault.Is.OfConcreteType<NHibernateUnitOfWork>();


    
 


    
    ForRequestedType<IRepository>().TheDefault.Is.OfConcreteType<NHibernateRepository>();


    
}

  





With a little luck and all of our mad skills, we should be able to talk to the database now. So we need to plumb our simple product object up to talk to NHibernate. We will do this with a mapping file, and since we are using FluentNHibernate we can do this strongly typed.



Make the following modifications to Product: Extend DomainEntity and get rid of Id Property, it is inherited




  

    
public class Product : DomainEntity


    
{


    
    public virtual string Name { get; set; }


    
    public virtual string Description { get; set; }


    
}

  





Add mapping file for Product:




  

    
namespace FubuSample.Core.Domain.Mapping


    
{


    
    public class ProductMap : ClassMap<Product>


    
    {


    
        public ProductMap()


    
        {


    
            Id(e => e.ID).GeneratedBy.GuidComb();


    
 


    
            Map(p => p.Name);


    
            Map(p => p.Description);


    
            


    
        }


    
    }


    
}

  





You may also want to setup your connection string at this point in the Web.Config file, mine looks like this:




  

    
<add name="MYDBKEY" connectionString="Data Source=LOCALHOST;initial catalog=FubuSample;Integrated Security=SSPI;" providerName="System.Data.SqlClient" />

  





I also created an empty database in my local SQL Server instance called “FubuSample” And then I went back to SQLServerSessionSourceConfiguration and changed the value of IsNewDatabase to return true. This will create the schema for the database when the application first runs. There is a multitude of different ways that we can handle this, but this was easy for the tutorial purposes.



Next we will add a behavior to our core project and tell FubuMVC to apply that behavior to all or our ControllerActions.



Create a class named “access_the_database_through_a_unit_of_work” in your Core.Web.Behaviors namespace. The contents will look like this:




  

    
public class access_the_database_through_a_unit_of_work : IControllerActionBehavior


    
{


    
    private readonly IUnitOfWork _unitOfWork;


    
 


    
    public access_the_database_through_a_unit_of_work(IUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public IControllerActionBehavior InsideBehavior { get; set; }


    
    public IInvocationResult Result { get; set; }


    
 


    
    public OUTPUT Invoke<INPUT, OUTPUT>(INPUT input, Func<INPUT, OUTPUT> func)


    
        where INPUT : class


    
        where OUTPUT : class


    
    {


    
        _unitOfWork.Initialize();


    
 


    
        try


    
        {


    
            var output = InsideBehavior.Invoke(input, func);


    
            Result = InsideBehavior.Result;


    
 


    
            _unitOfWork.Commit();


    
 


    
            return output;


    
        }


    
        catch


    
        {


    
            _unitOfWork.Rollback();


    
            throw;


    
        }


    
        finally


    
        {


    
            _unitOfWork.Dispose();


    
        }


    
    }


    
}

  





Now to tell FubuMVC what to do, open up Global.asax.cs or your Bootstrapper, wherever you are doing the configuration of FubuMVC. In this project we are doing it in Global.asax.cs Add a new behavior to the section that starts with “x.ByDefault.EveryControllerAction” so it looks like this:




  

    
x.ByDefault.EveryControllerAction(d =>


    
   {


    
       d.Will<execute_the_result>();


    
       d.Will<access_the_database_through_a_unit_of_work>();


    
   });

  





The last thing we will do is open up HomeController and add this code above the Index action:




  

    
private IRepository _repository;


    
 


    
public HomeController(IRepository repository)


    
{


    
    _repository = repository;


    
}

  





I also modified the Index action to go ahead and create some database values before we query for them just so we can test this thing. (I only did this for the tutorial, I swear) So modify the Index action to look like this:




  

    
public IndexViewModel Index(IndexSetupViewModel inModel)


    
{


    
    var prod1 = new Product {Name = "TestProduct1", Description = "This is a test product"};


    
 


    
    _repository.Save(prod1);


    
 


    
    var prod2 = new Product {Name = "TestProduct2", Description = "This is a test product"};


    
 


    
    _repository.Save(prod2);


    
 


    
    var outModel = new IndexViewModel();


    
 


    
    var productList = _repository.Query<Product>();


    
 


    
    outModel.Products = productList.ToList().Select(x => new ProductDisplay(x));


    
 


    
    return outModel;


    
}

  





Now with you should be able to run your web app and browse to /home and all this will be executed and you will be on your way to creating a whole bunch of persist able objects for use with your FubuMVC app.



As always, feedback is welcome.
]]>
			http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/feed/
		9
		
		
		Book review: NHibernate in Action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/?utm_source=rss&utm_medium=rss&utm_campaign=book-review-nhibernate-in-action
		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/#comments
		Sat, 14 Jun 2008 20:42:15 +0000
		Jan Van Ryswyck
				
		
		

		http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/
		
			kuate_cover150 Writing this book review feels kind of weird  because it hasn't actually hit the shelves yet. It is accessible however through the Manning Early Access Program. This book provides a clear insight of using NHibernate as the data access layer of your applications and beyond. 
 
The excessive amount of NHibernate features  isn't the only thing that is written down. There is also a good coverage of OO principles and Domain-Driven Design, although it isn't the primary objective of the book of course. This is especially true for the first and the last three chapters. If you've already read the nominal books DDD and you are familiar with Persistence Ignorance, then you can safely skim through these chapters unless you want to see the interpretation of the authors when it comes to these principles. If you are new to these concepts, then these chapters are of great value to wet your appetite.
 
Although this book covers a lot of ground, I would certainly recommend it when you're rather new to NHibernate and ORM's in general. I guess this still includes me, although I've been using NHibernate for quite some time now. If you already have some experience with NHibernate, then this book probably doesn't teach you that much. Still, it can quickly get you up to speed when you want to use a particular feature that you haven't used before. 
 
The only minor thing about this book is that I'm afraid that it will soon be out-of-date. The book only covers NHibernate 1.2.x and no features from the upcoming 2.0 release, which adds a lot of new and interesting features. It would be nice if the book already covered some of these features as most of them are ported from Hibernate itself, which is the original Java version.
 
On the other hand, this book provides an in-depth view of the basic features of NHibernate, which aren't necessarily going to change that much over time anyway.
 
Let me round off this post by saying that I'm really impressed by the list of books that Manning is going to release the next couple of months. These are the ones that I'm particularly interested in:
  
I already bought LINQ in Action and also read a lot of good things about C# in Depth, which I'm going to pick up soon.
 
Take care.
]]>
			http://elegantcode.com/2008/06/14/book-review-nhibernate-in-action/feed/
		7
		
		
		Integrating Castle Windsor and NHibernate with WCF
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/?utm_source=rss&utm_medium=rss&utm_campaign=integrating-castle-windsor-and-nhibernate-with-wcf
		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/#comments
		Sun, 18 May 2008 14:08:20 +0000
		Jan Van Ryswyck
				
		

		http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/
		
			Up until now, we were using the NHibernate facility of Castle Windsor for managing our NHibernate sessions in WCF. But, we want to have a session-per-request approach as one would use when integrating NHibernate with a regular web application. 
  
Yesterday I did a small spike to figure out how this should work. It turned out to be pretty easy. I used this excellent blog post written by Oran Dennison as my guide. 
  
First I created a class that implemented the IServiceBehavior interface.
  
   
public class DIServiceBehavior : IServiceBehavior
{
    private readonly ISessionFactory _sessionFactory;

    public DIServiceBehavior()
    {
        _sessionFactory = new Configuration()
            .Configure()
            .BuildSessionFactory();

        XmlConfigurator.Configure();    // Log4Net
    }

    public void ApplyDispatchBehavior(
             ServiceDescription serviceDescription, 
             ServiceHostBase serviceHostBase)
    {
        foreach(ChannelDispatcherBase cdb in 
                serviceHostBase.ChannelDispatchers)
        {
            ChannelDispatcher cd = cdb as ChannelDispatcher;
            if(cd != null)
            {
                foreach(EndpointDispatcher ed in cd.Endpoints)
                {
                    ed.DispatchRuntime.InstanceProvider =
                        new DIInstanceProvider
                            (serviceDescription.ServiceType,
                              _sessionFactory);
                }
            }
        }
    }

    public void AddBindingParameters(
                ServiceDescription serviceDescription, 
                ServiceHostBase serviceHostBase,
                Collection<ServiceEndpoint> endpoints, 
                BindingParameterCollection bindingParameters) 
    { }
    
    public void Validate(ServiceDescription serviceDescription, 
                         ServiceHostBase serviceHostBase) 
    { }
}





The SessionFactory is created in the constructor because the ApplyDispatchBehaviour method can be called multiple times (for each endpoint). 



The next step is to create an instance provider by creating a class that implements the IInstanceProvider:




  
public class DIInstanceProvider : IInstanceProvider
{
    private const String NHibernateSessionKey = 
        "NHibernate.Session";

    private readonly Type _serviceType;
    private IDependencyContainer _dependencyContainer;
    private readonly ISessionFactory _sessionFactory;
    private ISession _session;

    public DIInstanceProvider(Type serviceType,
                               ISessionFactory sessionFactory)
    {
        Debug.Assert(null != serviceType, 
                     "null != serviceType");
        _serviceType = serviceType;

        Debug.Assert(null != sessionFactory, 
                     "null = sessionFactory");
        _sessionFactory = sessionFactory;
    }

    public Object GetInstance(InstanceContext instanceContext)
    {
        return GetInstance(instanceContext, null);
    }

    public Object GetInstance(InstanceContext instanceContext, 
                                Message message)
    {
        _dependencyContainer = new DependencyContainer();

        _session = _sessionFactory.OpenSession();
        _dependencyContainer
          .AddComponentInstance(NHibernateSessionKey, _session);

        return _dependencyContainer.Resolve(_serviceType);
    }

    public void ReleaseInstance(InstanceContext instanceContext, 
                                 Object instance)
    {
        if(null != _session)
        {
            _session.Close();
            _session = null;
        }

        if(null != _dependencyContainer)
        {
            _dependencyContainer.Dispose();
            _dependencyContainer = null;
        }
    }
}





I created a wrapper class around for Castle Windsor named DependencyContainer.  The GetInstance method opens a new session using the SessionFactory object we instantiated in the service behavior class. The session object is then registered with Castle Windsor. We can now implement our repositories like this:




  
public class SomeAggregateRepository
{
    private ISession _session;

    public SomeAggregateRepository(ISession session)
    {
        _session = session;
    }
    
    public SomeAggregate Get(Int64 id) 
    {
        return _session.Get<SomeAggregate>(id);
    }
}





When our service operation has been executed, the NHibernate is released by the ReleaseInstance method. Finishing our example, we need to implement a custom ServiceHost and a ServiceHostFactory:




  
public class DIServiceHost : ServiceHost
{
    public DependencyInjectionServiceHost() 
        : base() 
    { }
    
    public DIServiceHost(Type serviceType, 
                         params Uri[] baseAddresses) 
        : base(serviceType, baseAddresses) 
    { }

    protected override void OnOpening()
    {
        Description.Behaviors.Add(new DIServiceBehavior());
        base.OnOpening();
    }
}

public class DIServiceHostFactory : ServiceHostFactory
{
    protected override ServiceHost CreateServiceHost(
            Type serviceType, Uri[] baseAddresses)
    {
        return new DIServiceHost(serviceType, baseAddresses);
    }
}





The custom ServiceHostFactory class can now be used in the ServiceHost file required when doing IIS hosting:




  
<%@ ServiceHost Language="C#" 
                Debug="true" 
                Service="WindsorService.MyWindsorService" 
                Factory="WindsorService.DIServiceHostFactory"
                CodeBehind="MyWindsorService.svc.cs" %>





There is also another way for achieving this that I will be investigating the next week or so using the WCF Integration Facility for Castle Windsor. For some reason it is not available in the current release of the Castle stack so I have to grab it from the trunk. 



If you have any thoughts, improvements or suggestions I'm glad to hear them from you, my dear reader. It's the only way I'll ever learn :-). 



Till next time.
]]>
			http://elegantcode.com/2008/05/18/integrating-castle-windsor-and-nhibernate-with-wcf/feed/
		9
		
		
		Implementing NHibernate Interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/?utm_source=rss&utm_medium=rss&utm_campaign=implementing-nhibernate-interceptors
		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/#comments
		Thu, 15 May 2008 18:29:26 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/
		
			One of the areas where NHibernate really shines is it's high extensibility features. The NHibernate API provides a massive amount of interfaces that can be implemented for your own custom extension pleasure. 
  
For me this is a nice change as opposed to the many sealed API's put out by the Redmond collective (WCF being the exception, the Entity Framework confirming the rule).
  
Anyhow, with great power comes great responsibility. Today I encountered a rather difficult problem with NHibernate that could have been easily prevented by reading the documentation (note to self: use the CTRL-Q shortcut of Resharper more often).
  
We have implemented an interceptor for automatically configuring audit information as described by this great post from Ray Houston. 
  
   
public class AuditInformationInterceptor 
    : EmptyInterceptor
{
    Boolean OnSave(Object entity, Object id, Object[] state, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }

    Boolean OnFlushDirty(Object entity, Object id, 
        Object[] currentState, Object[] previousState, 
        String[] propertyNames, IType[] types)
    {
        // Implementation
    }                  
}





The mistake we made is that we manipulated the audit information of the entity directly in the OnSave and OnFlushDirty methods. This only became apparent when saving an aggregate root with his child entities. Everything worked fine until we wanted to persist one of the child entities that should have been a piece of cake but turned out to be the messenger of trouble. NHibernate refused to perform an INSERT statement, but instead threw an UPDATE statement at us. 



After some debugging we found out that the audit information should have been manipulated through the state and currentState arguments of the OnSave and OnFlushDirty methods respectively.



The documentation of the OnSave method clearly states:



The interceptor may modify the state, which will be used for the SQL INSERT

    
and propagated to the persistent object



Lesson relearned. 



I'm off, reading some docs. Until next time.
]]>
			http://elegantcode.com/2008/05/15/implementing-nhibernate-interceptors/feed/
		3
		
		
		On Persistence
		http://elegantcode.com/2008/05/01/on-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=on-persistence
		http://elegantcode.com/2008/05/01/on-persistence/#comments
		Thu, 01 May 2008 19:18:43 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/05/01/on-persistence/
		
			Earlier this week, I managed to convince our very wise decision makers to start using NHibernate for our persistence layer. My team mate on the project describes how it went. While I was reading Jeremy's train of thoughts, the following four lines made me realize we did the right thing:
  
Why are teams still writing persistence code by hand?  There's a bazillion persistence tools out there that all save development costs in some way over writing data access code by hand.  With very few exceptions, I'd say that at this point that if you're writing ADO.Net code or SQL by hand, you're stealing money from your employer.  
  
As another co-worker and NHibernate fan thoughtfully mentioned while congratulating us:
  
A small step for man, but a giant leap for mankind.
  
Few. What a week this turns out to be.
]]>
			http://elegantcode.com/2008/05/01/on-persistence/feed/
		2
		
		
		NHibernate 2.0 and Cascading Deletes
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-20-and-cascading-deletes-2
		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/#comments
		Sat, 12 Apr 2008 18:58:12 +0000
		Jan Van Ryswyck
				

		http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/
		
			The first alpha version of NHibernate 2.0 has been released some time ago. Oren has put a nice overview of the new features and the bugs that are solved for this first drop. In spite the fact that they put the word 'alpha' in the version name, it is actually RTM quality! 
  
One of the great new additions is the on-delete attribute of the key element for mapping collections:
  
<set name="Permissions" inverse="true" cascade="save-update">
  <key name="Authorization" on-delete="cascade"/>
  <one-to-many class="Permission"/>
</set>



This particular feature solves the issue I've had with one-shot deletes on inverse collections (which I described here). Configuring it this way ensures that NHibernate relies on database-level ON CASCADE DELETE foreign key constraints. This implies that when an object with a collection of child objects is deleted, a single DELETE  statement is used to remove all children at once instead of individual DELETE statements for each child object (which are called orphans at this point).



There are some things that you have to take into account here. First, this option bypasses NHibernate's optimistic locking strategy for versioned data. Second, make sure that you configure cascade="save-update" instead of cascade="all" to prevent NHibernate from performing delete cascade checks. This is important when lazy loading is enabled for the collection because it prevents that NHibernate loads one-to-many associations into memory. 



I'm really excited about this new release. Kudos to the men and women who have put so much effort in building such a wonderful ORM solution!



Till next time
]]>
			http://elegantcode.com/2008/04/12/nhibernate-20-and-cascading-deletes-2/feed/
		0
		
		
		A New NHibernate Blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/?utm_source=rss&utm_medium=rss&utm_campaign=a-new-nhibernate-blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/#comments
		Tue, 01 Apr 2008 15:26:32 +0000
		Alex Mueller
				
		
		
		

		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/
		
			Craig Neuwirt recently started a blog focused on NHibernate, as mentioned by Ayende. NHibernate is an ORM tool I have used on current and past projects and it is something I feel I would like I want to study further. So far, Craig is walking us through NHibernate from the ground-up, with the latest and greatest. I anticipate this being an informative blog to follow.

The NHibernate FAQ
Craig Neuwirt
Hibernating Rhinos]]>
			http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/feed/
		2
		
		
		NHibernate IQuery to ISQLQuery Black Magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/?utm_source=rss&utm_medium=rss&utm_campaign=nhibernate-iquery-to-isqlquery-black-magic
		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/#comments
		Fri, 16 Nov 2007 06:12:55 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/
		
			posted on the forums and learned that: I'd run into a known bug / limitation.

Therefore I resorted to using ISQLQuery (yuk). I fixed several repository methods and then I ran into a very complicated IQuery. It was very painful to write the first time. In fact it was this experience that had caused me to change to using ICriteria as my default query method with specifications. I had a full suite of unit tests to protect me so I was confident that I could make the changes without breaking anything but I didn't want to do the conversion manually. Surely there was a trick?

It turns out that there is - NHibernate.Hql.Classic.QueryTranslator. The property that I needed is protected but thanks to a quick search of the forums I didn't even need to write my own reflection based method of calling it because someone had done it for me (thanks Nels). So what I did was take the HQL and convert it to SQL. I then did some string replacement to morph the SQL into what I needed. I am not proud of this but it was fast and it goes to show for flexible NHibernate is if you want to do some certifiable things.]]>
			http://elegantcode.com/2007/11/16/nhibernate-iquery-to-isqlquery-black-magic/feed/
		0
		
		
		DTOs / Presentation Model and ICriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/?utm_source=rss&utm_medium=rss&utm_campaign=dtos-presentation-model-and-icriteria
		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/#comments
		Tue, 06 Nov 2007 06:11:41 +0000
		Jason Grundy
				

		http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/
		
			NHibernate Projections I used HQL (IQuery) in the repository to define the query.

There are a some things that I don't like about HQL. For example the query is defined as a string. Strings are problematic because errors can't be detected at compile time. ICriteria queries go some way to alleviating this although they are certainly not perfect in this regard. You are writing tests against your repositories though aren't you?

But the reliance on strings is not the only problem with HQL. Today I needed to create a search screen. I wanted to use a variation of the technique that Ayende demonstrates here. With HQL the repository methods become ugly very quickly (and I mean wake up sweating at 2 am ugly). There is a mass of conditional string concatenation. And for each parameter I need to change 2 pieces of code (the code that builds the HQL and the code that binds the parameters).

So I decided to figure out how to use ICriteria to return a DTO. It transpires that the following code produces the same result as the HQL that I used before:

 



public List<InspectorDropDownDTO> GetAll()


{


 ICriteria q = session.CreateCriteria(typeof(Inspector), "i");


 q.CreateAlias("Person", "p");


 q.SetProjection(Projections.ProjectionList()


 .Add(Projections.Property("i.ID"), "InspectorID")


 .Add(Projections.Property("p.FirstName"), "FirstName")


 .Add(Projections.Property("p.LastName"), "LastName"));


 q.SetResultTransformer(Transformers.AliasToBean(typeof(InspectorDropDownDTO)));


 return q.List<InspectorDropDownDTO>();


}

It should be noted that the DTO itself is different with this method. A default constructor is now all that's needed because the AliasToBean transformer seems to work properly with ICriteria.

 



public class InspectorDropDownDTO


{


 private long _inspectorID;


 private string _firstName;


 private string _lastName;




 public long InspectorID { get { return _inspectorID; } set { _inspectorID = value; } }


 public string FirstName { get { return _firstName; } set { _firstName = value; } }


 public string LastName { get { return _lastName; } set { _lastName = value; } }


 public string FullName { get { return FirstName + " " + LastName; } }


}

Also note that you no longer need to import the DTO in an hbm.xml file.]]>
			http://elegantcode.com/2007/11/06/dtos-presentation-model-and-icriteria/feed/
		2
		
		
		DTOs Simplify Complex Screens
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/?utm_source=rss&utm_medium=rss&utm_campaign=a-new-nhibernate-blog
		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/#comments
		Tue, 01 Apr 2008 15:26:32 +0000
		Alex Mueller
				
		
		
		

		http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/
		
			Craig Neuwirt recently started a blog focused on NHibernate, as mentioned by Ayende. NHibernate is an ORM tool I have used on current and past projects and it is something I feel I would like I want to study further. So far, Craig is walking us through NHibernate from the ground-up, with the latest and greatest. I anticipate this being an informative blog to follow.

The NHibernate FAQ
Craig Neuwirt
Hibernating Rhinos]]>
			http://elegantcode.com/2008/04/01/a-new-nhibernate-blog/feed/
		2
		
		
		Elegant Code » NHibernate
	
	http://elegantcode.com
	
	Tue, 15 May 2012 10:00:00 +0000
	en
	hourly
	1
	http://wordpress.org/?v=3.3.1
		
		FubuMVC From Scratch – Part 4 Persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/?utm_source=rss&utm_medium=rss&utm_campaign=fubumvc-from-scratch-part-4-persistence
		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/#comments
		Wed, 25 Mar 2009 21:22:00 +0000
		Ryan Kelley
				
		
		
		
		
		
		

		http://elegantcode.com/2009/03/25/fubumvc-from-scratch-part-4-persistence/
		
			Previous posts in series:    
Persistence is a requirement in virtually every application that we write today, and now the time has come for us to add a persistence model to our FubuMVC app. I know I mentioned moving my samples to the FubuCart source, but I am going to go ahead and implement the persistence piece in the same project the previous articles using, FubuSample. I have also added all the code for this series to the FubuMVC-Contrib project
  
We will be implementing our persistence model to use NHibernate, Fluent NHibernate, Repository Pattern and UnitOfWork pattern all on top of SQL Express or standard. This will also work for sqllite and other database servers.
  
Class and Interfaces we have to implement: 
  
       
  • ISessionSourceConfiguration 
    •     
  • SQLServerSessionSourceConfiguration 
    •     
  • IUnitOfWork 
    •     
  • INHibernateUnitOfWork 
    •     
  • NHibernateUnitOfWork 
    •     
  • IRepository 
    •     
  • NHibernateRepository 
    •     
  • DomainEntity 
    •     
  • IDomainQuery 
    •     
  • FubuSamplePersistenceModel 
    •  
  
Note: I put the first two in the list in my Core.Config namespace, and the rest in Core.Persistence
  
Before we start you probably want to go ahead and add the following references to your core project and Web project
  
FubuMVC-Persist-Ref 
  
Let’s just work our way down the list and get these files implemented. 
  
ISessionSourceConfiguration
  
   
     
public interface ISessionSourceConfiguration


    
{


    
    bool IsNewDatabase { get; }


    
    ISessionSource CreateSessionSource(PersistenceModel model);


    
}

  





SQLServerSessionSourceConfiguration




  

    
public class SQLServerSessionSourceConfiguration : ISessionSourceConfiguration


    
{


    
    #region Implementation of ISessionSourceConfiguration


    
 


    
    public bool IsNewDatabase


    
    {


    
        get { return false; }


    
    }


    
 


    
    public ISessionSource CreateSessionSource(PersistenceModel model)


    
    {


    
        var properties = GetProperties();


    
        var source = new SessionSource(properties, model);


    
 


    
        create_schema_if_it_does_not_already_exist(source);


    
 


    
        return source;


    
    }


    
 


    
    private void create_schema_if_it_does_not_already_exist(ISessionSource source)


    
    {


    
        if (IsNewDatabase) source.BuildSchema();


    
    }


    
 


    
    protected IDictionary<string, string> GetProperties()


    
    {


    
        MsSqlConfiguration config = MsSqlConfiguration.MsSql2005;


    
        config.ConnectionString.FromConnectionStringWithKey(“MYDBKEY”);


    
        config.ShowSql();


    
        config.UseOuterJoin();


    
 


    
        return config.ToProperties();


    
    }


    
    #endregion


    
}

  





A quick note here: We told SQLServerSessionSourceConfiguration to use a connection string from the app settings file (Web.Config) with a key of “MYDBKEY” This will be important later.



IUnitOfWork




  

    
public interface IUnitOfWork : IDisposable


    
{


    
    void Initialize();


    
    void Commit();


    
    void Rollback();


    
}

  





INHibernateUnitOfWork




  

    
public interface INHibernateUnitOfWork : IUnitOfWork


    
{


    
    ISession CurrentSession { get; }


    
}

  





NHibernateUnitOfWork




  

    
public class NHibernateUnitOfWork : INHibernateUnitOfWork


    
{


    
    private ITransaction _transaction;


    
    private bool _isDisposed;


    
    private readonly ISessionSource _source;


    
    private bool _isInitialized;


    
 


    
    public NHibernateUnitOfWork(ISessionSource source)


    
    {


    
        _source = source;


    
    }


    
 


    
    public void Initialize()


    
    {


    
        should_not_currently_be_disposed();


    
 


    
        CurrentSession = _source.CreateSession();


    
        begin_new_transaction();


    
 


    
        _isInitialized = true;


    
    }


    
 


    
    public ISession CurrentSession { get; private set; }


    
 


    
    public void Commit()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Commit();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void begin_new_transaction()


    
    {


    
        if (_transaction != null)


    
        {


    
            _transaction.Dispose();


    
        }


    
 


    
        _transaction = CurrentSession.BeginTransaction();


    
    }


    
 


    
    public void Rollback()


    
    {


    
        should_not_currently_be_disposed();


    
        should_be_initialized_first();


    
 


    
        _transaction.Rollback();


    
 


    
        begin_new_transaction();


    
    }


    
 


    
    private void should_not_currently_be_disposed()


    
    {


    
        if (_isDisposed) throw new ObjectDisposedException(GetType().Name);


    
    }


    
 


    
    private void should_be_initialized_first()


    
    {


    
        if (!_isInitialized) throw new InvalidOperationException("Must initialize (call Initialize()) on NHibernateUnitOfWork before commiting or rolling back");


    
    }


    
 


    
    public void Dispose()


    
    {


    
        if (_isDisposed || !_isInitialized) return;


    
 


    
        _transaction.Dispose();


    
        CurrentSession.Dispose();


    
 


    
        _isDisposed = true;


    
    }


    
}

  





IRepository




  

    
public interface IRepository


    
{


    
    void Save<ENTITY>(ENTITY entity)


    
        where ENTITY : DomainEntity;


    
 


    
    ENTITY Load<ENTITY>(Guid id)


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>()


    
        where ENTITY : DomainEntity;


    
 


    
    IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery)


    
        where ENTITY : DomainEntity;


    
 


    
    void Delete<ENTITY>(ENTITY entity);


    
 


    
    void DeleteAll<ENTITY>();


    
}

  





NHibernateRepository




  

    
public class NHibernateRepository : IRepository


    
{


    
    private readonly INHibernateUnitOfWork _unitOfWork;


    
 


    
    public NHibernateRepository(INHibernateUnitOfWork unitOfWork)


    
    {


    
        _unitOfWork = unitOfWork;


    
    }


    
 


    
    public void Save<ENTITY>(ENTITY entity) where ENTITY : DomainEntity


    
    {


    
        _unitOfWork.CurrentSession.SaveOrUpdate(entity);


    
    }


    
 


    
    public ENTITY Load<ENTITY>(Guid id) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Load<ENTITY>(id);


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>() where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>();


    
    }


    
 


    
    public IQueryable<ENTITY> Query<ENTITY>(IDomainQuery<ENTITY> whereQuery) where ENTITY : DomainEntity


    
    {


    
        return _unitOfWork.CurrentSession.Linq<ENTITY>().Where(whereQuery.Expression);


    
    }


    
 


    
    public void Delete<ENTITY>(ENTITY entity)


    
    {


    
        _unitOfWork.CurrentSession.Delete(entity);   


    
    }


    
 


    
    public void DeleteAll<ENTITY>()


    
    {


    
        var query = String.Format("from {0}", typeof(ENTITY).Name);


    
        _unitOfWork.CurrentSession.Delete(query);   


    
    }


    
}

  





DomainEntity



Note: I put both of these classes in my Core.Domain namespace, also XML comments are in Source Repository




  

    
public class DomainEntity : IEquatable<DomainEntity>


    
{


    
    public virtual Guid ID { get; set; }


    
 


    
    public virtual bool Equals(DomainEntity other)


    
    {


    
        if (ReferenceEquals(null, other)) return false;


    
        if (ReferenceEquals(this, other)) return true;


    
        return other.ID.Equals(ID);


    
    }


    
 


    
    public override bool Equals(object obj)


    
    {


    
        if (ReferenceEquals(null, obj)) return false;


    
        if (ReferenceEquals(this, obj)) return true;


    
        if (obj.GetType() != GetType()) return false;


    
        return Equals((DomainEntity)obj);


    
    }


    
 


    
    public override int GetHashCode()


    
    {


    
        return ID.GetHashCode();


    
    }


    
 


    
    public static bool operator ==(DomainEntity left, DomainEntity right)


    
    {


    
        return Equals(left, right);


    
    }


    
 


    
    public static bool operator !=(DomainEntity left, DomainEntity right)


    
    {


    
        return !Equals(left, right);


    
    }


    
}

  





IDomainQuery




  

    
public interface IDomainQuery<ENTITY>


    
    where ENTITY : DomainEntity


    
{


    
    Expression<Func<ENTITY, bool>> Expression { get; }


    
}

  





FubuSamplePersistenceModel