Re: [webbeans-dev] Re: Producer fields on EJBs

I thought through this some, and bounced ideas off Andy. Gavin, I'm not sure that producer fields on SLSBs makes much sense - SLSBs instance state is undefined I think (some EJB expert correct if I'm wrong ;-). I think the spec should say that the behaviour of producer fields on SLSBs is undefined. Assuming the above, I would still argue for a getFieldValue SPI that throws IllegalStateException if invoked on an SLSB reference - and I think this removes the issue Ken has with a many-to-one instances.

I'm slipping this for the upcoming release as we are too far from consensus. On 6 Apr 2009, at 18:22, Pete Muir wrote: > > On 6 Apr 2009, at 18:00, Kenneth Saks wrote: > >> >> On Apr 6, 2009, at 12:31 PM, Pete Muir wrote: >> >>> Carlo, Ken, Andrew, >>> >>> JSR-299 supports the notion of a producer field. By adding the >>> annotation @Produces to a field, you make it into a bean, which can >>> be used as the source of injections. The field can also be >>> associated with a scope. When you first look up an instance of a >>> bean, the field value is accessed, and stored in the context for >>> it's lifetime. >>> >>> As we deal with EJB references, we can't directly access the field >>> value (using reflection) so I think we should use the SPI here. >>> >>> I propose we add a method with this signature to the >>> SessionObjectReference we previously created for the purpose of >>> casting/removing EJBs >>> https://svn.jboss.org/repos/webbeans/ri/trunk/spi/src/main/java/org/jboss... >>> >> >> There isn't necessarily a one-to-one relationship between an ejb >> reference and a bean instance. For stateless session beans, any one >> of the bean instances can be used for any invocation. >> >> Can't this behavior be handled by the web beans interceptor? By >> definition, each interceptor instance has the same life cycle as its >> associated bean instance, and the bean instance is available via the >> Interceptor InvocationContext. > > I did consider this, but not sure how to retrieve the result > invocationContext.getTarget() at the time it is needed for accessing > the producer field. We can't just store it from the construction point > onwards (serializability) and I can't see a way to access it at some > other point in the lifecycle - the only way to run an @AroundInvoke is > to call a method, and in this case which method would you run, and how > would you guarantee it has no side effects? > >> >> >>> >>> /** >>> * Retrieve the value of a (possibly private) field >>> * >>> * @param field >>> * the field to retrieve the value of >>> * @return the retrieved value >>> * @throws IllegalArgumentException >>> * if the field doesn't exist on this session object >>> instance >>> */ >>> public Object getFieldValue(Field field); >>> >>> Any comments? >>> >>> >>> On 29 Mar 2009, at 22:57, Pete Muir wrote: >>> >>>> Ok, I would think that some language in the spec to hint at this >>>> might be good, as instances of session beans elsewhere in the spec >>>> implies a EJB reference. >>>> >>>> On 29 Mar 2009, at 18:04, Gavin King wrote: >>>> >>>>> Yes, this is a good question - the 299 implementation would need >>>>> direct integration with the EJB container for this. (Not the only >>>>> place this is needed.) >>>>> >>>>> >>>>> On Sat, Mar 28, 2009 at 7:18 PM, Pete Muir <pmuir(a)redhat.com&gt; wrote: >>>>>> Hey >>>>>> >>>>>> Not quite sure how this is supposed to work as everywhere we hold a >>>>>> reference (proxy) to the EJB, and therefore don't have access to the >>>>>> instance and therefore can't get hold of the fields. Any pointers? >>>>>> >>>>>> Thanks! >>>>>> >>>>>> >>>>>> -- >>>>>> Pete Muir >>>>>> http://www.seamframework.org >>>>>> http://in.relation.to/Bloggers/Pete >>>>>> >>>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> Gavin King >>>>> gavin.king(a)gmail.com >>>>> http://in.relation.to/Bloggers/Gavin >>>>> http://hibernate.org >>>>> http://seamframework.org >>>> >>>> -- >>>> Pete Muir >>>> http://www.seamframework.org >>>> http://in.relation.to/Bloggers/Pete >>>> >>>> _______________________________________________ >>>> webbeans-dev mailing list >>>> webbeans-dev(a)lists.jboss.org >>>> https://lists.jboss.org/mailman/listinfo/webbeans-dev >>> >>> -- >>> Pete Muir >>> http://www.seamframework.org >>> http://in.relation.to/Bloggers/Pete >>> >> >> _______________________________________________ >> webbeans-dev mailing list >> webbeans-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/webbeans-dev > > -- > Pete Muir > http://www.seamframework.org > http://in.relation.to/Bloggers/Pete > > _______________________________________________ > webbeans-dev mailing list > webbeans-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/webbeans-dev -- Pete Muir http://www.seamframework.org http://in.relation.to/Bloggers/Pete _______________________________________________ webbeans-dev mailing list webbeans-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/webbeans-dev