[cdi-dev] Tests on observer resolution

[Pete Muir]

Ken’s book is correct in this I think.

On 17 Mar 2014, at 11:56, John D. Ament <john.d.ament at gmail.com> wrote:

> Correct, I don't believe best match is in any of the CDI spec.
> 
> However, this comes straight from Ken's book:
> 
> Say we have observer methods such as the following:
> 
> public void afterFictionBookAdded(@Observes @Book(FICTION)
>  @Added Book book) { ... }
> 
> public void afterBookAdded(@Observes @Added Book book) { ... }
> 
> public void onBookEvent(@Observes Book book) { ... }
> 
> In such cases, only afterFictionBookAdded() will be called as it
> matches the fired event with @Added and @Book(FICTION).
> 
> Now say we had an observer method such as the following:
> 
> public void afterAdding(@Observes @Any Book book) { ... }
> 
> The preceding observer method would also be notified, as @Any informs
> Weld that we want to be notified of all Book events, irrespective of
> what event qualifiers may be set.
> 
> On Mon, Mar 17, 2014 at 7:25 AM, Pete Muir <pmuir at redhat.com> wrote:
>> There are no "best match" semantics in CDI I know of...
>> 
>> On 16 Mar 2014, at 23:56, John D. Ament <john.d.ament at gmail.com> wrote:
>> 
>>> Funny that this comes up now.  I actually hacked into my coworker's
>>> code using an observer on any object.
>>> 
>>> I always assumed the use of @Any in the examples came from a different
>>> version of the event observer pattern where it was a best match, not
>>> an any match.
>>> 
>>> On Sun, Mar 16, 2014 at 1:51 PM, Pete Muir <pmuir at redhat.com> wrote:
>>>> Yeah, agreed, this is something I've puzzled over before.
>>>> 
>>>> On 6 Mar 2014, at 11:51, Antoine Sabot-Durand <antoine at sabot-durand.net> wrote:
>>>> 
>>>>> Hi all
>>>>> 
>>>>> 
>>>>> Yesterday when reviewing Martin Pull Request [1] regarding CDI 422 [2], we started a discussion about Observer Resolution about a possible issue in the spec. I will not repeat what was said on the IRC, if you're interested you can check the transcript [3] from 09:43.
>>>>> 
>>>>> To check if this was an issue or not I did some test this morning with different implementations. You can grab the tests on Github [4]
>>>>> 
>>>>> Good news : OWB and Weld (1.x and 2.x) have the same behavior : the one describe in the current spec, so there are no issue on this point.
>>>>> The only strange thing for me is that @Any seems totally useless regarding events firing
>>>>> 
>>>>> If you write :
>>>>> @Inject Event<Payload> payLoadEvent;
>>>>> or
>>>>> @Inject @Any Event<Payload> payLoadEvent;
>>>>> 
>>>>> You'll always be allowed call payLoadEvent.select(new QualifierLiteral()) in both case...
>>>>> 
>>>>> Perhaps this point can be discussed to see if we remove @Any from the examples in the spec or if we enforce its usage in the specification...
>>>>> 
>>>>> Antoine
>>>>> 
>>>>> [1] https://github.com/cdi-spec/cdi/pull/207
>>>>> [2] https://issues.jboss.org/browse/CDI-422
>>>>> [3] http://transcripts.jboss.org/channel/irc.freenode.org/%23jsr346/2014/%23jsr346.2014-03-05.log.html
>>>>> [4] https://github.com/antoinesd/EventsTest
>>>>> _______________________________________________
>>>>> cdi-dev mailing list
>>>>> cdi-dev at lists.jboss.org
>>>>> https://lists.jboss.org/mailman/listinfo/cdi-dev
>>>> 
>>>> 
>>>> _______________________________________________
>>>> cdi-dev mailing list
>>>> cdi-dev at lists.jboss.org
>>>> https://lists.jboss.org/mailman/listinfo/cdi-dev
>>