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
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[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(a)uk.ibm.com>
To: weld-dev(a)lists.jboss.org
Cc: "Emily Jiang" <EMIJIANG(a)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?
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