[webbeans-dev] Dynamic lookup

[Nicklas Karlsson]

I like it. @Observable/@Obtainable probably covers 90% of the cases
where the user would normally work with a Manager

On 12/7/08, Gavin King <gavin at hibernate.org> wrote:
> An issue that Bill brought up on the last concall, and that has been
> bothering me for a while is that we have a few different cases where
> the application wants to perform a dynamic lookup:
>
> (1) when binding types vary at runtime
> (2) when the dependency is optional
> (3) when you want to obtain an object that belongs to a child manager
>
> But the only way we let you do this is by injecting the Manager
> object, which has really evolved into an SPI-type integration point
> and has a whole bundle of operations that should not really be in the
> view of the application. Furthermore, it requires use of
> AnnotationLiteral for all binding types, which is pretty nasty.
>
> So I think we need to provide a different API, one that is more
> appropriate to usage by the application.
>
> Other solutions do have sugar for this: Guice has an injectable
> Provider<T> interface, Spring let's you write an abstract method which
> is implemented by the container.
>
> I think we should model a lookup interface on what we have for event
> firing. Analogous to:
>
>    @Observable @SomeBinding Event<SomeEventType> someEvent;
>
> We should let you inject:
>
>    @Obtainable @SomeBinding Instance<SomeType> someInstance;
>
> Which would let you call someInstance.get() to obtain an instance of
> the SomeType with SomeBinding.
>
> This would involve the following new interface:
>
>    public interface Instance<T> {
>       public T get(Annotation... bindings);
>       public boolean isSatisfied(Annotation... bindings);
>    }
>
> This is a *much* simpler API to use.
>
> The isDefined() method would let you determine if any Web Bean exists
> that satisfies the API type and bindings.
>
> --
> Gavin King
> gavin.king at gmail.com
> http://in.relation.to/Bloggers/Gavin
> http://hibernate.org
> http://seamframework.org
>
>
>
> --
> Gavin King
> gavin.king at gmail.com
> http://in.relation.to/Bloggers/Gavin
> http://hibernate.org
> http://seamframework.org
> _______________________________________________
> webbeans-dev mailing list
> webbeans-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/webbeans-dev
>

-- 
Sent from Gmail for mobile | mobile.google.com

---
Nik