[cdi-dev] Should javax.enterprise.inject.Produces be inherited?

[Mark Struberg]

> Right now inheritance of managed beans is itself problematic, as 

> injecting the base class can cause these ambiguous resolutions.

Yes, that's why we originally introduced @Typed.



Your sample wont work as an Alternative as it extends a concrete class and doesn't implement any interface.
Did you mean @Specializes?
Note that with @Alternative you won't make the original producer go away.You would also need to add @Alternative to the producer method imo. The rules for making an alternative producer method are really a bit confusing ;) I think the most portable way is to annotate both the class and the producer method with @Alternative.


LieGrue,
strub


On Monday, 12 September 2016, 0:57, John Ament <john.ament at spartasystems.com> wrote:
>
>Hi Emily,
>
>
>I disagree, at least it doesn't add any new ambiguous injections.  The use-case is specifically to Specialized/Alternative beans.  Right now inheritance of managed beans is itself problematic, as injecting the base class can cause these ambiguous resolutions.
>
>
>The example I sent out actually works correctly (in weld at least), really my propose is to remove the need to have Produces a second time and update the spec to clarify what happens here (FWIW, I don't believe the case is currently described in the spec), hopefully to say that qualifiers and scopes from the base method remain in effect, unless explicitly overridden.
>
>
>John
>
>
>
>________________________________
> 
>From: Emily Jiang <EMIJIANG at uk.ibm.com>
>Sent: Sunday, September 11, 2016 5:59 PM
>To: John Ament
>Cc: cdi-dev
>Subject: Re: [cdi-dev] Should javax.enterprise.inject.Produces be inherited? 
> 
>I think this is very problematic as you will get AmbiguousResolutionException all the time once we introduce this inheritance. 
>
>Many thanks,
>Emily
>===========================
>Emily Jiang
>WebSphere Application Server, CDI Development Lead 
> 
>MP 211, DE3A20, Winchester, Hampshire, England, SO21 2JN
>Phone:  +44 (0)1962 816278  Internal: 246278
>
>Email: emijiang at uk.ibm.com 
>Lotus Notes: Emily Jiang/UK/IBM at IBMGB
>
>
>
>
>From:        John Ament <john.ament at spartasystems.com> 
>To:        cdi-dev <cdi-dev at lists.jboss.org> 
>Date:        11/09/2016 20:04 
>Subject:        [cdi-dev] Should javax.enterprise.inject.Produces be inherited? 
>Sent by:        cdi-dev-bounces at lists.jboss.org 
>>________________________________
> 
>
>
>All, 
>
>I was just thinking about alternatives and producer methods.  Suppose I have the following bean: 
>
>@ApplicationScoped 
>public class Boop { 
>
>    @Produces 
>    @ApplicationScoped 
>    public Simpler makeSimpler() { 
>        return new Simpler("Boop"); 
>    } 
>} 
>
>If I want to override the producer method, I need to declare fully: 
>
>@Alternative 
>@Priority(100) 
>@ApplicationScoped 
>public class BoopAlternative extends Boop{ 
>    @Override 
>    @Produces 
>    public Simpler makeSimpler() { 
>        return new Simpler("Boop2"); 
>    } 
>} 
>
>For some reason, scopes are inherited, but the produces annotation is not.  At least in the case of a producer method, it seems like it would be useful for @Produces to be inherited as well. 
>
>John 
>
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