javagenericsjakarta-eecdideltaspike

Programmatic lookup of all beans of parametrized interface

Given the type:

public interface Foo<T, X extends A>{...}

I need to use programmatic lookup to find bean that implement the given interface regardless of parameter types. Because of type safe resolution this returns an empty set:

final Set<Bean<?>> foos= BeanManagerProvider.getInstance().getBeanManager().getBeans(Foo.class, new AnyLit());

or via Deltaspike:

org.apache.deltaspike.core.api.provider.BeanProvider.getDependent(Foo.class, new AnyLit())

where AnyLit is: 

private static class AnyLit extends AnnotationLiteral<Any> implements Any
{

}

Is there any way to get around this?

Thanks

Solution

  • I think you could make use of TypeLiteral - a special CDI class which can hold the type and it's parameters. Through this you can specify what exactly you want in approximately this way:

    TypeLiteral<Foo<Object, Object>> typeLiteral = new TypeLiteral<Foo<Object, Object>>() {};
BeanManager bm; //assuming you can retrieve BM somehow
bm.getBeans(typeLiteral.getType(), new AnyLit());

    Now, this is (I hope) in accord with CDI assignability rules (WARNING: generics ahead, grab a coffee before reading). In short, you want to use Object as a type so that: