blazey.registry

Why?

Applying some recommended practices such as favour polymorphism over conditions can sometimes sounds pithy but how might one actually practices this? Blazey.registry extends Castle Windsor to automatically apply the specification with a predicate parameter if you inject all candidates like so:

public class CarQuery
{
    private readonly Registrar<ICar> _carRegistry;

    public CarQuery(Registrar<ICar> carRegistry)
    {
        _carRegistry = carRegistry;
    }

    public ICar GetRedCar()
    {
        return _carRegistry.Get(Color.Red);
    }
}

public class Ferrari : ICar
{
    public bool IsSatisfiedBy(Color color)
    {
        return color == Color.Red;
    }

    public void Drive()
    {
    }
}

public class Lamborghini : ICar
{
    public bool IsSatisfiedBy(Color color)
    {
        return color == Color.Yellow;
    }

    public void Drive()
    {
    }
}

What is this doing?

All registered instances of the generic parameter (i.e. ICar) are resolved. The first instance to return true if a member that homogenizes to: issatisfiedby, satisfied, cansatisfy, satisfy, ismatch, match is returned by the registry.

How do I use it?

Add the registry faciltiy:

container.AddFacility<RegistryFacility>();

Register dependencies and services as normal:

_container.Register(
    AllTypes.FromThisAssembly().BasedOn<IDependency>().WithServiceAllInterfaces(),
    Component.For<Service>());

Instead of injecting an array of IDependency inject the Registrar type with the dependency type as an open genric parameter like so:

public class Service
{
    private readonly Registrar<IDependency> _registrar;

    public Service(Registrar<IDependency> registrar)
    {
        _registrar = registrar;
    }
    .
    .
}

(c) Blazey Software Ltd