[cdi-dev] [weld-dev] Question about the spec for BeanManager.getBeans

[Emily Jiang]

Matej,

Thanks for your quick reply!
I think the spec is quite clear by saying the candidates of typesafe 
resolutions defined in Performing typesafe resolutions... surely a 
disabled bean cannot be a candidate. it is simply disquailified. 

It did not say eliminate all beans but one though. I think it should be 
eliminate disqualified ones and leave all qualified at least. 

I am sending to cdi-dev for clarification. Antoine, please comment.

Many thanks,
Emily
===========================
Emily Jiang
WebSphere Application Server, Liberty Architect for MicroProfile and CDI
 
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:   Matej Novotny <manovotn at redhat.com>
To:     Benjamin Confino <BENJAMIC at uk.ibm.com>
Cc:     weld-dev at lists.jboss.org, Emily Jiang <EMIJIANG at uk.ibm.com>
Date:   24/08/2018 16:17
Subject:        Re: [weld-dev] Question about the spec for 
BeanManager.getBeans



Hi

Looking at spec 11.3.6. Obtaining a Bean by type[1] I can see that the 
paragraph ends with "according to the rules for candidates of typesafe 
resolution defined in Performing typesafe resolution.".
The important word here is *candidates* IMO. 
The way typesafe resolution is defined, both the original bean and the 
alternatives are candidates. According to spec, the original bean is still 
considered enabled[2]
Note that CDI spec doesn't say that @Alternative would completely 
eliminate the original bean, it just takes precedence during resolution 
(as opposed to what specialization does[3]).

Last but not least, one thought - if the getBeans() method was to perform 
a typesafe resolution and eliminate all but one bean - why would it return 
a Set (and not throw unsatisfied/ambiguous exceptions)? :)

Matej
______________________________________________________________________________
[1] 
http://docs.jboss.org/cdi/spec/1.2/cdi-spec.html#bm_obtain_bean_by_type

[2] 
http://docs.jboss.org/cdi/spec/1.2/cdi-spec.html#enablement

[3] 
http://docs.jboss.org/cdi/spec/1.2/cdi-spec.html#specialization



----- Original Message -----
> From: "Benjamin Confino" <BENJAMIC at uk.ibm.com>
> To: weld-dev at lists.jboss.org
> Cc: "Emily Jiang" <EMIJIANG at uk.ibm.com>
> Sent: Friday, August 24, 2018 3:10:05 PM
> Subject: [weld-dev] Question about the spec for BeanManager.getBeans
> 
> Hello
> 
> I was made aware of the difference on the return of
> beanManager.getBeans(Object.class) between OWB and Weld
> 
> In OWB, it returns all beans, unless there is an enabled @alternative 
within
> the application. If there is an enabled @alternative getBeans() only 
returns
> beans annotated @alternative.
> 
> However, in Weld, it returns all beans even with an enabled 
@alternative.
> 
> The JavaDoc for BeanMnanager says "according to the rules of typesafe
> resolution" and in the CDI 1.0 spec under typesafe resolution I find one
> mention of alternatives: “When an ambiguous dependency exists, the 
container
> attempts to resolve the ambiguity. The container eliminates all eligible
> beans that are not alternatives, except for producer methods and fields 
of
> beans that are alternatives.” (This text is also in the CDI 1.2 spec)
> 
> However this would imply that if there are no enabled @Alternatives an
> ambiguous resolution like beanManager.getBeans(Object.class) should 
discard
> everything. In this case, the Weld behaviour is incorrect.
> beanManager.getBeans() should only return the resolved or enabled beans.
> 
> Regards
> Benjamin
> 
> Can someone verify this?
> Unless stated otherwise above:
> IBM United Kingdom Limited - Registered in England and Wales with number
> 741598.
> Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 
3AU
> 
> _______________________________________________
> weld-dev mailing list
> weld-dev at lists.jboss.org
> 
https://lists.jboss.org/mailman/listinfo/weld-dev





Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU

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