[cdi-dev] How about documenting Alternatives on producers ?

[Antonio Goncalves]

BTW, if I take the @Alternative producer out (so there is no more
@Alternative) but leave the <alternative> element, the Weld error message
is :

WELD-001422: Enabled alternative
<class>org.agoncal.cdi.PrefixProducer</class> in file:/beans.xml at 7 is not
an alternative

Again, the error message is very "bean" oriented, don't you think ?

Antonio

On Tue, Oct 21, 2014 at 4:10 PM, Antonio Goncalves <
antonio.goncalves at gmail.com> wrote:

> Hi all,
>
> I often use code such as the one below: one bean, two producers and one
> producer is an alternative (not the bean) :
>
> *public class *PrefixProducer
> {
>    @Produces
>    *public *String *prefixNonAlt *= *"non-alternative"*;
>
>    @Produces
> *   @Alternative*
>    *public *String *prefixAlt *= *"alternative"*;
> }
>
> I enable the alternative, as usual, by declaring the bean in the beans.xml
> :
>
> <*alternatives*>
>   <*class*>org.agoncal.cdi.PrefixProducer</*class*>
> </*alternatives*>
>
> This works fine, no problem. But I just realized that Intellij IDEA
> displays the warning "Alternative class expected here". I've looked around,
> read the spec, the Weld documentation, and didn't find any example of the
> code above. I think people are unware of this. The only reference of
> alternative producers I found is in the spec :
>
> *5.1.1.2*
> *An alternative is selected for the bean archive if either:*
>
> ** the alternative is a producer method, field or resource, and the bean
> class that declares the method or field is listed*
>
> I think for such easy use cases (i.e PrefixProducer) there is no need to
> multiply beans, so the code is fine and easy to read. But the code you see
> around, tend to multiply beans (people think that Alternatives are *only*
> for beans, not for producers).
>
> Shouldn't the spec/Weld documentation mention this case a bit more often,
> by giving an example ?
>
> WDYT ?
>
> Antonio
>
>
>
>
>
>
>
>
>
>
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-- 
Antonio Goncalves
Software architect, Java Champion and Pluralsight author

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