[cdi-dev] Extensions and spec-related observer method injection points question

Matej Novotny manovotn at redhat.com
Fri Feb 17 01:08:24 EST 2017

Hi, comment inline.

----- Original Message -----
> From: "Laird Nelson" <ljnelson at gmail.com>
> To: cdi-dev at 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
> 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.
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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