Type Pool

The Type Pool concept comes from working with the Fubu code base its a pretty simple class that I find makes type scanning much simpler.

{{< highlight csharp >}} namespace v23athletics.infrastructure.types { using System; using System.Collections.Generic; using System.Linq; using System.Reflection; using Fasterflect;

public class TypePool { readonly IList<Assembly> _assemblies; Lazy<IEnumerable<Type>> _types;

public TypePool(params Assembly[] assemblies) { _assemblies = new List<Assembly>(assemblies); _types = new Lazy<IEnumerable<Type>>(buildUp); } public TypePool() : this(new Assembly[0]) { }

public Assembly[] Assemblies { get { return _assemblies.ToArray(); } }

//add a source to scan. public void AddSource(Assembly assembly) { _assemblies.Add(assembly); _types = new Lazy<IEnumerable<Type>>(buildUp); }

//for LINQ queries public IEnumerable<Type> Query() { return _types.Value; }

//if you want to have the scans be seperate testable classes public IEnumerable<Type> Scan<TScanner>() where TScanner : TypeScan, new() { var scanner = new TScanner(); return _types.Value.Where(scanner.Matches); }

public IEnumerable<Type> Scan(Func<Type, bool> predicate) { return _types.Value.Where(predicate); }

//function to build the types up lazily IEnumerable<Type> buildUp() { return _assemblies.SelectMany(a => a.ExportedTypes); }

public IEnumerable<Type> FindImplementorsOf<TInterface>() { return Scan(t => t.Implements<TInterface>()); } }

} {{< /highlight >}}

{{< highlight csharp >}}

var typePool = new TypePool(typeof(MarkerType).Assembly); var settingTypes = typePool.Query().Where(t=>t.Name.EndsWith("Settings"));

{{< /highlight >}}

I use this guy to help me find types so that i can register them in my IoC container. Now most containers have their own scanning conventions, but one thing they tend to lack is a way to pass around the 'Application Assemblies' which is is something the TypePool can do. By passing the TypePool into the lower services or IoC 'Registries' I can use there scanning capabilities or I can use my own.

{{< highlight csharp >}}

public class MySubRegistry : Registry { public MySubRegistry(TypePool pool) { Scan(scanner => { scanner.AddAllTypes<IService>(); foreach(var ass in pool.Assemblies) scanner.Assembly(ass); }) } }

public class MySubModule : Module { TypePool _pool;

public MySubModule(TypePool pool) { _pool = pool; }

public void RegisterComponents(ContainerBuilder builder) { var types = _pool.Query().Where( t => t.Implements<IService>()); builder.RegisterTypes(types) .As<IService>(); } } } {{< /highlight >}}