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https://issues.jboss.org/browse/CDI-408?page=com.atlassian.jira.plugin.sy...
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Antoine Sabot-Durand edited comment on CDI-408 at 3/18/14 10:59 AM:
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Yes [~pmuir] and [~jason.greene] we all agree on that (I hope so). For me it was implicit
that option 3) includes a mention in the spec regarding that, while option 2) would warn
the user at boot time.
Now the majority chose the option 3 (aka the RTFM option) we should be sure that the spec
include something about it : "you shouldn't use default bean discovery mode to
use Producers and Observers or annotate the beans that contains them with bean defining
annotation (that's pretty clear). Should we spread it in different chapters (Producers
and Event) or should we put it somewhere else ?
was (Author: antoinesabot-durand):
Yes [~pmuir] and [~jason.greene] we all agrre on that (I hope so) for me it was
implicit that option 3) includes a mention in the spec regarding that, while option 2)
would warn the user at boot time.
Now the majority chose the option 3 (aka the RTFM option) we should be sure that the spec
include something about it : "you shouldn't use default bean discovery mode to
use Producers and Observers or annotate the beans that contains them with bean defining
annotation (that's pretty clear). Should we spread it in different chapters (Producers
and Event) or should we put it somewhere else ?
bean-discovery-mode="annotated" and Producers/Observers in
@Dependent beans
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Key: CDI-408
URL:
https://issues.jboss.org/browse/CDI-408
Project: CDI Specification Issues
Issue Type: Clarification
Components: Beans
Reporter: Jens Schumann
Assignee: Antoine Sabot-Durand
Labels: CDI_spec_chge
Fix For: 1.2 Proposed
Right now bean-discovery-mode="annotated" skips beans that are not annotated
with an bean-defining annotation even if they contain an observer method or producer
method/field. I would not recommend having (not annotated) @Dependent beans with @Observes
or @Produces - I just had them by accident while playing around with Wildfly.
However there are two impacts:
1. Someone might be confused by ignored @Producer's. Not a major issue here, the CDI
runtime will report it. We could optionally document the behavior in the spec, so it's
clear to everyone. However I think it's inconsistent, since @Produces may contain a
scope (and has a default scope too). Therefore I would vote for @Produces support in
bean-discovery-mode="annotated". Of course the enclosing class is not a managed
bean that may be injected somewhere.
2. Since Observer methods in "not annotated" beans fail silently this can be a
major issue for applications, especially if you migrate from CDI 1.0 (CDI 1.0 source code
and CDI 1.0 thinking model). Therefore I believe @Observer methods have to be included in
bean-discovery-mode="annotated" even if the enclosing bean does not have a
bean-defining annotation. Of course the enclosing class is not a managed bean that may be
injected somewhere.
I understand that the proposal above might have negative impacts on class scanning
performance in bean-discovery-mode="annotated". However silently failing
@Observes can be a major cause of defects that have to be treated because of technical and
political reasons. Technical - because it may cause bugs. And political - because in my
experience many people are still skeptical that CDI events are a trustworthy
achievement[1]. Possibly skipped observer methods won't make live easier.
If you believe the proposal would kill the original intent of
bean-discovery-mode="annotated" please document the impact for Producers and
Observers in the spec and even in the XSD.
--
[1] I have trained a couple hundred people in using CDI and CDI events. And every time I
have to argument against the uncertainty on event delivery: "How do I know which
observers are active?", "Who ensures that event's are delivered?"... I
personally LOVE events;)
Btw: Which JIRA version is CDI 1.1 Final?
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