Hi all,

First Laird, thanks you for all your feedback on CDI, they are very helpful.

This section is indeed not clear, but my understanding is this one:

1) As we mention the fact that BeanManager.fire() can be invoked in an extension lifecycle event observer, it makes sense to say observer on lifecycle payload are supported in extension, otherwise firing an event during the BeforeBeanDiscovery lifecycle event for instance would be useless since the only CDI elements "discovered" at this step are portable extensions

I tested in various Weld and OWB version, observers on non lifecycle payload are called when BeanManager.fire() is called

2) If extension can contain observers with custom payload that can be invoked during container bootstrapping, it is quite understandable that adding parameters to these observer can bring issue: matching bean may not have been discovered yet and will result in an error. So for me, it makes sense to say that having an observer injecting something else than BeanManager in an extension is not safe and shouldn't be supported

In other words

void MyObserver(@Observes MyPayload payload) { ... )

and

void MyObserver(@Observes MyPayload payload, BeanManager bm) { ... )

are supported in an extension, but

void MyObserver(@Observes MyPayload payload, MyBean bean) { ... )

is not because MyBean may be not discovered yet when observer will be triggered.

Weld doesn't support it, while OWB does, so we face a non portable feature here ;).

3) A side effect of your mail made me also realise that we mention BeanManger.fire() in this section despite its deprecation in CDI 2.0 (we should mention BeanManager.getEvent().select().fire())

This section really needs clarification, I'll create the ticket when we agree on what is part of the spec and not ;).

Antoine

On Fri, Feb 17, 2017 at 9:16 AM Martin Kouba <mkouba@redhat.com> wrote:

Dne 17.2.2017 v 07:08 Matej Novotny napsal(a):
> Hi, comment inline.
>
> ----- Original Message -----
>> From: "Laird Nelson" <ljnelson@gmail.com>
>> To: cdi-dev@lists.jboss.org
>> Sent: Thursday, February 16, 2017 11:11:41 PM
>> Subject: [cdi-dev] Extensions and spec-related observer method injection points question
>>
>> This section (
>> http://docs.jboss.org/cdi/spec/2.0-PFD/cdi-spec.html#init_events ) says: "If
>> other beans [other than the BeanManager ] are injected into an [portable]
>> extension’s observer methods, non-portable behavior results."
>>
>> Rephrased: a portable extension's observer methods must have a minimum of one
>> parameter (the event being observed) and a maximum of two parameters (that
>> plus the BeanManager ), and none other if you want to stay truly portable.
>
> That's correct interpretation.
>
>> For true container lifecycle events, I understand this (you don't have beans
>> to inject yet). But given that a bean must be provided by the container for
>> a portable extension (
>> http://docs.jboss.org/cdi/spec/2.0-PFD/cdi-spec.html#init_events ), wouldn't
>> it be reasonable to permit extra injection points in a portable extension's
>> non -container-lifecycle-event-observing observer methods?
>>
>> Concretely, I'd like to do this:
>>
>> // In my portable extension
>> private static final void doSomethingAtStartup(@Observes
>> @Initialized(ApplicationScoped.class) final Object event, final Frobnicator
>> someBean) {
>> someBean.doSomething();
>> }
>
> While you cannot do this, you can still get hold of BeanManager and use it to resolve your bean.
>
>>
>> ...but that would seem to be in violation of the specification. Could someone

It's not a violation, it's a non-portable behavior. Weld should not
complain about the injection points of the doSomethingAtStartup()
observer method.

>> kindly explain why?
>
> Not really sure, perhaps Martin or Antoine can share the details.
> But I would say this could create quite some confusion if in some observer you could inject certain beans and in others you couldn't.

Yes, I think the possible confusion was the only reason.

> Even in your sample, you can only inject AppScoped beans, so imagine you do such observer for, say, SessionScoped, what can you inject there?
> SessionScoped for sure, how about Req? Conversation?
>
>>
>> Thanks,
>> Best,
>> Laird
>>
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--
Martin Kouba
Senior Software Engineer
Red Hat, Czech Republic
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