[seam-dev] Retrieving the Bean object for an interceptor

[Gavin King]

On Thu, Apr 22, 2010 at 12:38 AM, Marius Bogoevici
<marius.bogoevici at gmail.com> wrote:
> On 10-04-21 10:36 PM, Stuart Douglas wrote:
>> I have attempted to add a temporary fix for this issue to weld-extensions to allow interceptors to get at the AnnotatedType of the object being intercepted.
>>
>> The extension wraps the InjectionTarget of Beans that need this functionality, and the inject method of the InjectionTarget stores a mapping from the instance to the AnnotatedType in a WeakHashMap.
>>
>> I have a few questions:
>>
>> - Is InvocationContext.getTarget() guaranteed to return the instance of the bean or can it return a proxy? If it can return a proxy this technique is not going to work.
>>
> The Interceptor specification says just that "getTarget() returns the
> associated target instance", so that would normally mean  "the original
> intercepted instance". The introduction of decorators made things more
> complicated, and in the current implementation (1.0.1), getTarget() will
> return the decorator proxy if the bean has both interceptors and
> decorators.

Then that is a bug, since it is contrary to the specified behavior of
getTarget().

> However, once we move to subclassing (1.0.2), the call will
> return the single instrumented instance, which is essentially a subclass
> of the bean class. It would be necessary to retrieve the original bean
> class from that. But I can see a few options for doing that, one being a
> mixin interface with methods that can retrieve information about the
> original type of the target object.

Hrm. That's a problem I had not thought of with the subclassing
approach. The assumption in EJB is that getTarget() returns an
unintercepted/undecorated reference. Urm.


-- 
Gavin King
gavin.king at gmail.com
http://in.relation.to/Bloggers/Gavin
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