While trying to coerce Windsor into wrapping an implementation with a random number of decorators, i've stumbled upon the following:
i have 3 decorators and an implementation all using the same interface.
if you run this code, windsor resolves icommandhandler<stringcommand>
as implementation
, which, as far as i can tell, is expected behaviour, because the typed implementation can not be registered with the open typed decorators.
However, if you uncomment the line container.Register(Component.For<ICommandHandler<stringCommand>>().ImplementedBy<Decorator1<stringCommand>>());
, all three decorators will be used to resolve implementation
, which is the desired result (sort of : ).
class Program
{
static void Main(string[] args)
{
var container = new WindsorContainer();
container.Register(Component.For(typeof(ICommandHandler<>)).ImplementedBy(typeof(Decorator1<>)));
container.Register(Component.For(typeof(ICommandHandler<>)).ImplementedBy(typeof(Decorator2<>)));
container.Register(Component.For(typeof(ICommandHandler<>)).ImplementedBy(typeof(Decorator3<>)));
//uncomment the line below and watch the magic happen
//container.Register(Component.For<ICommandHandler<stringCommand>>().ImplementedBy<Decorator1<stringCommand>>());
container.Register(Component.For<ICommandHandler<stringCommand>>().ImplementedBy<implementation>());
var stringCommandHandler = container.Resolve<ICommandHandler<stringCommand>>();
var command = new stringCommand();
stringCommandHandler.Handle(command);
Console.WriteLine(command.s);
Console.ReadKey();
}
}
public interface ICommandHandler<T>
{
void Handle(T t);
}
public class stringCommand
{
public string s { get; set; }
}
public abstract class Decorator<T> : ICommandHandler<T>
{
public abstract void Handle(T t);
};
public class Decorator1<T> : Decorator<T>
where T : stringCommand
{
private ICommandHandler<T> _handler;
public Decorator1(ICommandHandler<T> handler)
{
_handler = handler;
}
public override void Handle(T t)
{
t.s += "Decorator1;";
_handler.Handle(t);
}
}
public class Decorator2<T> : Decorator<T>
where T : stringCommand
{
private ICommandHandler<T> _handler;
public Decorator2(ICommandHandler<T> handler)
{
_handler = handler;
}
public override void Handle(T t)
{
t.s += "Decorator2;";
_handler.Handle(t);
}
}
public class Decorator3<T> : Decorator<T>
where T : stringCommand
{
private ICommandHandler<T> _handler;
public Decorator3(ICommandHandler<T> handler)
{
_handler = handler;
}
public override void Handle(T t)
{
t.s += "Decorator3;";
_handler.Handle(t);
}
}
public class implementation : ICommandHandler<stringCommand>
{
public void Handle(stringCommand t)
{
t.s += "implementation;";
}
}
Why exactly is this happening, is this a feature of windsor that i am not aware of? Is there perhaps a different way to achieve the same effect? (without resorting to reflection)
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