Re: [webbeans-dev] Producer fields on EJBs

Date: Jul 31st 2009 Time: 9:30 to 10:30am PST Dial-in number: (866) 839-8145 Intl: (865)524-6352 Access code: 9032012

On Jul 31, 2009, at 10:52 AM, Pete Muir wrote: > Hi Guys, > > We need to resurrect this discussion. Why don't we go over this on today's concall. > > I've committed a proposed SPI getFieldValue() method to http://anonsvn.jboss.org/repos/webbeans/ri/trunk/spi/src/main/java/org/jb... > which I will wire into Web Beans now. > > Can anyone say if they vehemently disagree with this approach, or > have some improvements to suggest? :-) > > Thanks! > > Pete > > On 16 Apr 2009, at 07:51, Andrew Lee Rubinger wrote: > >> Pete Muir wrote: >>> 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. >> >> UnsupportedOperationException perhaps? >> >>> 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 >> >> -- >> Andrew Lee Rubinger >> Sr. Software Engineer >> JBoss, a division of Red Hat, Inc. >> http://exitcondition.alrubinger.com >> _______________________________________________ >> webbeans-dev mailing list >> webbeans-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/webbeans-dev >