[cdi-dev] Producer#dispose(T instance) and similar

[Mark Struberg]

Oki, sounds ok so far. 

What about InjectionTarget<T> ?

InjectionTarget#postConstruct(T instance)
InjectionTarget#preDestroy(T instance)


They don't have a CreationalContext parameter. Where do they take the interceptors? And of course there _are_ interceptors allowed for InjectionTargets imo.
That could only work if 'instance' is a proxy already, isn't?


LieGrue,
strub



----- Original Message -----
> From: Pete Muir <pmuir at redhat.com>
> To: Arne Limburg <arne.limburg at openknowledge.de>
> Cc: Mark Struberg <struberg at yahoo.de>; cdi-dev <cdi-dev at lists.jboss.org>
> Sent: Wednesday, December 5, 2012 4:55 PM
> Subject: Re: [cdi-dev] Producer#dispose(T instance) and similar
> 
> Hey Arne,
> 
> No, they can't :-) It's specifically called out in Chapter 8 and Chapter 
> 9 that decorators and interceptors aren't applied to the result of producer 
> methods.
> 
> Pete
> 
> On 5 Dec 2012, at 14:47, Arne Limburg wrote:
> 
>>  Hi Pete,
>> 
>> 
>>  A little of topic and I don't want to disturb your discussion, but:
>> 
>>  Beans produced by producer methods CAN have interceptors as stereotypes
>>  are supported on producer methods.
>> 
>>  Cheers,
>>  Arne
>> 
>>  Am 04.12.12 17:46 schrieb "Pete Muir" unter 
> <pmuir at redhat.com>:
>> 
>>>  Hi Mark, I'll try to answer inline, but I'm missing a bit of 
> background
>>>  about what you are doing...
>>> 
>>>  On 4 Dec 2012, at 14:20, Mark Struberg wrote:
>>> 
>>>>  Another problem probably being an interceptor on the @Disposes 
> method
>>>>  itself.
>>>>  Where does the Proucer#dispose(T instance) get the interceptor 
> from?
>>>> 
>>>>  LieGrue,
>>>>  strub
>>>> 
>>>> 
>>>> 
>>>> 
>>>>  ----- Original Message -----
>>>>>  From: Mark Struberg <struberg at yahoo.de>
>>>>>  To: cdi-dev <cdi-dev at lists.jboss.org>
>>>>>  Cc: 
>>>>>  Sent: Tuesday, December 4, 2012 3:16 PM
>>>>>  Subject: [cdi-dev] Producer#dispose(T instance) and similar
>>>>> 
>>>>>  Hi!
>>>>> 
>>>>>  I'm currently stumbling over implementing
>>>>> 
>>>>>  Producer#dispose(T instance) properly
>>>>> 
>>>>>  The Producer#produce(CreationalContext)
>>>>> 
>>>>>  has the CreationalContext parameter but the dispose
>>> 
>>>  Right, it would have been good to have included it here. I'm not 
> sure why
>>>  it wasn't, however I don't believe that it causes a problem 
> with the CDI
>>>  1.0 spec, but just limits us going forward.
>>> 
>>>>>  and others do not have it.
>>> 
>>>  Yes.
>>> 
>>>>> 
>>>>>  Problem here is that a Producer could probably get exchanged 
> via a
>>>>>  portable 
>>>>>  extension via ProcessProducer#setProducer(Producer)
>>> 
>>>  Yes, this is definitely supported
>>> 
>>>>>  so it could be from a
>>>>>  foreign source which must not know anything about container
>>>>>  implementation 
>>>>>  details.
>>> 
>>>  Yes.
>>> 
>>>  I think the critical part of the spec to understand this is 11.2. 
> I'm
>>>  quoting here from the CDI 1.1 spec, into which we have add the
>>>  clarification that "The instance returned by produce() may be a 
> proxy.".
>>>  The part about building interceptors and decorators is there in CDI 
> 1.0.
>>> 
>>>>  For a Producer that represents a class:
>>>> 
>>>>      € produce() calls the constructor annotated @Inject if it 
> exists, or
>>>>  the constructor with no parameters otherwise, as defined in
>>>>  [instantiation], and returns the resulting instance. If the class 
> has
>>>>  interceptors,produce() is responsible for building the interceptors 
> and
>>>>  decorators of the instance. The instance returned by produce() may 
> be a
>>>>  proxy.
>>>> 
>>>>      € dispose() does nothing.
>>> 
>>>  and
>>> 
>>>>  For a Producer that represents a producer method or field:
>>>> 
>>>>      € produce() calls the producer method on, or accesses the 
> producer
>>>>  field of, a contextual instance of the bean that declares the 
> producer
>>>>  method, as defined in [methods].
>>>> 
>>>>      € dispose() calls the disposer method, if any, on a contextual
>>>>  instance of the bean that declares the disposer method, as defined 
> in
>>>>  [methods], or performs any additional required cleanup, if any, to
>>>>  destroy state associated with a resource.
>>> 
>>>  Now, let me start to break down your sentence :-)
>>> 
>>>>> 
>>>>>  What now about having an interceptor on @PreDestroy?
>>> 
>>>  For a start, it's worth remembering interceptors can only be 
> associated
>>>  with beans defined by a class. If the bean is a producer, then you 
> can't
>>>  intercept the instance produced (only the invocation of the producer).
>>> 
>>>>>  This is what you get if
>>>>>  your interceptor has a at PreDestroy method himself as per the
>>>>>  interceptors and EJB
>>>>>  specs. That would mean that the instance passed to dispose() 
> whould be
>>>>>  the 
>>>>>  proxy? That purely sounds wrong to me.
>>> 
>>>  Based on my comment from above, I think it's clear that dispose() 
> should
>>>  never try to invoke predestroy methods. That is the job of
>>>  InjectionTarget.preDestroy(). I would expect a proxy to be passed to
>>>  preDestroy().
>>> 
>>>> 
>>>> 
>>>>> 
>>>>>  Another issue being InjectionTarget#postConstruct() only having 
> the
>>>>>  instance T 
>>>>>  as well. Now what about @PostConstruct interceptors as defined 
> in the
>>>>>  interceptors spec?
>>> 
>>>  Again, I would expect a proxy to be passed to postConstruct(). Anyway,
>>>  I'm not sure why you need access to the creational context in the
>>>  postConstruct()? Here you should just invoke the postConstruct 
> callback,
>>>  which should create any new dependent objects.
>>> 
>>>>>  Currently we have a dirty hack in OWB to pass over the
>>>>>  CreationalContext which
>>>>>  contains the dependent scoped interceptors for our own 
> Producers and
>>>>>  InjectionTargets. But I have no clue yet how that should get
>>>>>  implemented if one
>>>>>  plugs in a portable Producer via an Extension ^^
>>>>> 
>>>>>  Who is responsible of performing the interception? The 
> Producer? Or
>>>>>  must the 
>>>>>  instance being handed into already be a Proxy?
>>> 
>>>  The instance returned from produce() should have interceptors and
>>>  decorators applied.
>>> 
>>>  Please let me know if above makes sense, it took me a while to work out
>>>  whether what was defined was sane. After quite a lot of thinking +
>>>  talking to Jozef and Stuart I came to the conclusion it was, but  if 
> you
>>>  can poke holes then please do!
>>>  _______________________________________________
>>>  cdi-dev mailing list
>>>  cdi-dev at lists.jboss.org
>>>  https://lists.jboss.org/mailman/listinfo/cdi-dev
>> 
>