Service locator for generics

Question

I have say a dozen types T which inherit from EntityObject and IDataObject. I have generic the following interface

IDataMa         


        

Answer 1

Here is a neat solution if having the locator as singleton is fine:

static class Locator
{
    private static class LocatorEntry where T : ...
    {
        public static IDataManager instance;
    }

    public static void Register(IDataManager instance) where T : ...
    {
        LocatorEntry.instance = instance;
    }

    public static IDataManager GetInstance() where T : ...
    {
        return LocatorEntry.instance;
    }
}

If you cannot implement the locator as singleton, I believe there is no there around creating a Dictionary and do some casts:

class Locator
{
    private readonly Dictionary instances;

    public Locator
    {
        this.instances = new Dictionary();
    }

    public void Register(IDataManager instance) where T : ...
    {
        this.instances[typeof(T)] = instance;
    }

    public IDataManager GetInstance() where T : ...
    {
        return (IDataManager)this.instances[typeof(T)];
    }
}