I'm going to tread carefully when arguing this point because I am far from a master at generics. Unfortunately, it seems that the non-normative section of the generics documentation is not consistent with the generics API. For instance, in the documentation, a type parameter is described as a special kind of type variable. But in the generics API, they are two separate things (ParameterizedType and TypeVariable). But I may be mistaken.

With that said, the example I gave fails in Web Beans. Let me give a full example:

public class Artist<T> { ... }

public class Solo { ... }

public class TuneSelect {
    @Any Event<Artist<Solo>> soloArtistEvent;

    public void soloArtistPlaying(Artist<Solo> artist)
    {
        soloArtistEvent.fire(artist);
    }
}

Here's the exception Web Beans spits out.

java.lang.IllegalArgumentException: Event type org.jboss.jsr299.tck.tests.event.eventTypes.Artist is not allowed because it is a generic
    at org.jboss.webbeans.BeanManagerImpl.fireEvent(BeanManagerImpl.java:798)
    at org.jboss.webbeans.event.EventImpl.fire(EventImpl.java:76)

=> same result for soloArtistEvent.fire(new Artist<Solo>())

If you believe that should be valid, then I will simply mark it as ri-broken.

I see what you are saying though in that what is not allowed is a type which is tied to the method parameters, hence acting as a type variable.

-Dan

On Fri, Jul 24, 2009 at 12:46 PM, Pete Muir <pmuir@redhat.com> wrote:
No, the spec prohibits type variables in event objects and event types, it doesn't prohibit type parameters.

This isn't legal

public class Foo{

@Produces <T> Bar make(@Any Event<T> event) {
...

}

and we do need to error at deployment time for such a declaration. Do we?

What you show *is* valid.

It's also not valid to actually pass an event object with a type variable, but it's extremely hard to actually find code that will compile and pass the above deployment test, but still do this and do this so I can't find an example right now ;-)



On 24 Jul 2009, at 17:28, Dan Allen wrote:

In several places, the specification reiterates that an event type may not contain a type variable. However, it appears that this restriction is only enforced at runtime when the event object is passed to either Event#fire() or BeanManager#fireEvent() method. I would suggest that an validation check be added so that the container detects an illegal Event definition at deployment type. Here's an example of an illegal definition (from my understanding):

public class VoterRegistration<T> { ... }

@Any Event<VoterRegistration<Democrat>> democratRegisteredEvent;

-Dan

--
Dan Allen
Senior Software Engineer, Red Hat | Author of Seam in Action
Registered Linux User #231597

http://mojavelinux.com
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http://in.relation.to/Bloggers/Dan
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--
Dan Allen
Senior Software Engineer, Red Hat | Author of Seam in Action
Registered Linux User #231597

http://mojavelinux.com
http://mojavelinux.com/seaminaction
http://in.relation.to/Bloggers/Dan