[seam-dev] CDI EG requires feedback

[Pete Muir]

This would still work, you are replacing an existing annotated type, not adding a new one for the same type.

We're talking about having an AnnotatedType<Foo>, and adding another one of AnnotatedType<Foo>.

On 15 Aug 2012, at 17:42, Lincoln Baxter, III wrote:

> I believe that Forge creates new Annotated Types to replace the existing one in the event-bus extension. This is done so that Qualifiers may be added to parameters of event observers.
> 
> You can see the code here. I'm not sure if this is related to your discussion, but it seems close so I thought I would mention it: 
> 
> https://github.com/forge/core/blob/master/event-bus-api/src/main/java/org/jboss/forge/bus/cdi/ObserverCaptureExtension.java
> 
> This extension took a good deal of work to produce, and is used throughout Forge. As long as we can capture events like we are doing here, it could be re-implemented, but it would potentially be a lot of work.
> 
> ~Lincoln
> 
> On Wed, Aug 15, 2012 at 9:17 AM, Pete Muir <pmuir at redhat.com> wrote:
> All, the CDI EG requires feedback on an item in the spec which is not clear, and has been implemented differently between implementations, and is not TCK tested. As Seam-dev contains lots of extensions authors, requesting feedback. Please either send direct to me, or post to cdi-dev at lists.jboss.org :-)
> 
> Stuart, your feedback on this would be good, as it relates to XML config.
> 
> ------------------------------------------------------------------------------------------------------------------------------------------------
> 
> Multiple Annotated Types
> ====================
> 
> https://issues.jboss.org/browse/CDI-58
> 
> This concerns whether there can be greater than one annotated type per class instance in the JVM. Gavin intended there should be, principally to support an XML configuration dialect, which could introduce multiple versions of a class, each with a different qualifier. However, this is not TCK tested, and implementations vary in how they support this.
> 
> We discussed that this makes an implementation considerably more complex (as there is no easy way to uniquely identify an annotated type e.g. for serialization), and also is pretty confusing for a user (as you now get multiple ProcessAnnotatedType events for each class, making it hard to know which one you want to change).
> 
> We looked at alternative solutions, and concluded that if all use cases can be satisfied by adding a new bean, rather than a new annotated type, we would like to explicitly specify that there is only one annotated type per class instance. In CDI 1.1 it is already much easier to add and manipulate beans from annotated types, so we believe that the correct thing here is take this route.
> 
> ------------------------------------------------------------------------------------------------------------------------------------------------
> 
> Does anyone create multiple AnnotatedTypes per class instance? If so, can you please describe:
> 
> a) why you need to do this
> b) whether you could reimplement by directly creating beans (given that CDI 1.1 allows you to [1])
> c) how much effort it would be to reimplement/how much of your codebase this would affect
> 
> Thanks!
> 
> Pete
> 
> [1]
> 
> BeanAttributes ba = beanManager.cerateBeanAttributes(annotatedType);
> InjectionTarget it = beanmanager.createInjectionTarget(annotatedType);
> Bean b = beanManager.createBean(ba, clazz, it);
> 
> or
> 
> BeanAttributes ba = beanManager.cerateBeanAttributes(annotatedFieldOrMethod);
> Producer p = beanmanager.createProducer(annotatedFieldOrMethod);
> Bean b = beanManager.createBean(ba, clazz, p);
> 
> The Bean can then be registered using
> 
> afterBeanDiscovery.addBean(b);
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> 
> 
> 
> -- 
> Lincoln Baxter, III
> http://ocpsoft.org
> "Simpler is better."