+1
This will be fabulous -- hooks for decorators and interceptors here.
On Fri, Apr 9, 2010 at 10:01 AM, Pete Muir <pmuir_at_redhat.com> wrote:
> Any CDI based bean container will likely need to do this - if you take a
> look Section 6.4 of the CDI spec:
>
> "all @Dependent scoped contextual instances created during evaluation of a
> Unified EL expression in a JSP or JSF page are destroyed when the evaluation
> completes."
>
> You can see that we have a need to know when an expression starts to be
> evaluated (so that we can start collecting the dependent objects) and stops
> being evaluated (so that we can destroy the dependent objects). We also need
> a add stuff to the collection as the expression evaluates (for which the
> ELContext.putContext() method is ideal). So, IOW we have three requirements:
>
> * be notified when an expression evaluation starts
> * be notified when an expression evaluation ends
> * have the ELContext used for expression evaluation be made available as
> part of the notification.
>
> As starting point, we could add an interface like:
>
> interface ExpressionEvaluationCallback {
>
> void beforeEvaluation(ELContext ctx);
> void afterEvaluation(ELContext ctx);
>
> }
>
> However, IMO, a better (more powerful, fits well with the interceptors
> spec) is reuse the approach there whereby an interceptor method is annotated
> @AroundInvoke, and takes an argument of type InvocationContext, which allows
> access to contextual objects such as (in our case) ELContext, and also has a
> proceed() method which can be used to call the original object (in our case
> the built in evaluation).
>
> Thoughts?
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