The killer argument is that nobody succeed to provide a way to prevent opt-in and keep backward compaibility. The problem comes from the fact that producer and consumer can be in different jar compiled with different version of CDI  and running on CDI 2.0 preventing using opt-out.
If you have the solution without opt-in I’m all ears.


Le 19 mars 2015 à 16:52, José Paumard <jose.paumard@gmail.com> a écrit :

> So it seems impossible to avoid opt-in on the observer side
What is the "killer" argument for that ? 

José

2015-03-19 16:44 GMT+01:00 Antoine Sabot-Durand <antoine@sabot-durand.net>:

Le 19 mars 2015 à 15:51, Romain Manni-Bucau <rmannibucau@gmail.com> a écrit :

sounds like a quick and dirty solution to me. @Async will arrive

Yes like in “Async is coming” ;)

- maybe too early today - but adding @ObservesAsync just cause we dont have yet @Async will make this API obselete pretty quickly isn't it (already cause of EJB actually).

and if we add an @Async in our spec you think it’s better ?


Do we really want this feature at this price?

#1 requested feature by users.

If yes AsyncObserves sounds an acceptable compromise but still will mess up the API IMO.

The question is “Is it more or less messy than @Async @Observes?"  I don’t know… It has pros and cons as I listed... 



Romain Manni-Bucau
@rmannibucau |  Blog | Github | LinkedIn | Tomitriber

2015-03-19 15:36 GMT+01:00 Antoine Sabot-Durand <antoine@sabot-durand.net>:
Hi guys,


So it seems impossible to avoid opt-in on the observer side for the sake of awkward compatibility.
Adding a member to @Observes could also be a source of issues when old CDI lib will be used with CDI 2.0 runtime. Some of us (including me) don’t want to add an @Async annotation to CDI spec, so perhaps we should add an async alternative to @Observes with an @AsyncObserves or @ObservesAsync ?

So it would be

public void myObserver(@AsyncObserves payload) {}

instead of

@Async
public void myObserver(@Observes payload) {}


Pros :
- it’s a cleaner way to manage the opt-in than to put 2 annotations or add a member to an existing one
- it could have new members related to async behavior (context propagation, concurrent scenario, etc…)
- As it won’t be in legacy code no risk to see old observers called asynchronously  

Cons :
- Still not clear for users when fire() is called to see @AsyncObserves launched synchronously
- Yet another annotation added

wdyt ?

Antoine

_______________________________________________
cdi-dev mailing list
cdi-dev@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/cdi-dev

Note that for all code provided on this list, the provider licenses the code under the Apache License, Version 2 (http://www.apache.org/licenses/LICENSE-2.0.html). For all other ideas provided on this list, the provider waives all patent and other intellectual property rights inherent in such information.



_______________________________________________
cdi-dev mailing list
cdi-dev@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/cdi-dev

Note that for all code provided on this list, the provider licenses the code under the Apache License, Version 2 (http://www.apache.org/licenses/LICENSE-2.0.html). For all other ideas provided on this list, the provider waives all patent and other intellectual property rights inherent in such information.



--
M : +33 6 76 82 91 47