[webbeans-dev] Producer fields on EJBs

Andrew Lee Rubinger alr at jboss.org
Fri Jul 31 11:00:22 EDT 2009 

Sure, see you guys there.

S,
ALR

On 07/31/2009 10:58 AM, Pete Muir wrote:
> ALR, Carlo, Jaikiran, can one of you join? It's at
>
>> 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 31 Jul 2009, at 15:57, Kenneth Saks wrote:
>
>>
>> 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/jboss/webbeans/ejb/api/SessionObjectReference.java
>>> 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/webbeans/ejb/api/SessionObjectReference.java
>>>>>>>>
>>>>>>>
>>>>>>> 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 at redhat.com>
>>>>>>>>>> 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 at 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 at 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 at 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 at 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 at 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 at lists.jboss.org
>>>> https://lists.jboss.org/mailman/listinfo/webbeans-dev
>>>
>>
>

-- 
Andrew Lee Rubinger
Sr. Software Engineer
JBoss by Red Hat
http://exitcondition.alrubinger.com

More information about the weld-dev mailing list