Re: ambiguous dependencies when using multiple qualifiers
OK, thanks for the clarification!
Regards,
Jakob
2010/9/29 Joseph Bergmark bergm...@apache.org:
I think you hit the nail on the head with your last paragraph.
Basically it only matters that the bean (or producer in this case)
matches all of the qualifiers on the injection point. From the
perspective of the specification it doesn't matter if the bean has
extra qualifiers beyond those on the injection point. Section 5.3 is
another key section here.
Sincerely,
Joe
On Wed, Sep 29, 2010 at 12:30 PM, Jakob Korherr jakob.korh...@gmail.com
wrote:
Hi,
I tested some scenarios when using multiple qualifiers for test-cases
in MyFaces CODI and stumbled upon the following scenario, which is not
totally clear to me.
Image you have the following producer methods:
�...@produces
�...@qualifier2
�...@applicationscoped
public ProducerBean createWithQualifier2()
{
return new ProducerBean();
}
�...@produces
�...@qualifier1
�...@qualifier2
�...@applicationscoped
public ProducerBean createWithQualifier1And2()
{
return new ProducerBean();
}
and you want to inject the instances produced by these producers. Now
you can use @Inject @Qualifier1 or @Inject @Qualifier1 @Qualifier2,
but when using @Inject @Qualifier2 you will get an exception, because
the injection point is ambiguous (both producers provide @Qualifier2).
However I was wondering if this is really unresolvable ambiguous,
because if you think about it, it would make sence to take the
producer createWithQualifier2() in this scenario (because the other
one provides additional qualifiers).
I also took a look in the CDI spec about this, but could only find the
following from section 2.3.4: A bean may only be injected to an
injection point if it has all the qualifiers of the injection point.
Of course this applies to both producers and thus, yes, it's kinda
ambiguous.
WDYT?
Regards,
Jakob
--
Jakob Korherr
blog: http://www.jakobk.com
twitter: http://twitter.com/jakobkorherr
work: http://www.irian.at
--
Jakob Korherr
blog: http://www.jakobk.com
twitter: http://twitter.com/jakobkorherr
work: http://www.irian.at
Re: ambiguous dependencies when using multiple qualifiers
I also took a look in the CDI spec about this, but could only find the following from section 2.3.4: A bean may only be injected to an injection point if it has all the qualifiers of the injection point. Of course this applies to both producers and thus, yes, it's kinda ambiguous. 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. If there is exactly one bean remaining, the container will select this bean, and the ambiguous dependency is called resolvable. The spec says both producers satisfy the injection point, and does not allow it to discard the one with additional qualifiers. -- Eric Covener cove...@gmail.com
Re: ambiguous dependencies when using multiple qualifiers
I think you hit the nail on the head with your last paragraph.
Basically it only matters that the bean (or producer in this case)
matches all of the qualifiers on the injection point. From the
perspective of the specification it doesn't matter if the bean has
extra qualifiers beyond those on the injection point. Section 5.3 is
another key section here.
Sincerely,
Joe
On Wed, Sep 29, 2010 at 12:30 PM, Jakob Korherr jakob.korh...@gmail.com wrote:
Hi,
I tested some scenarios when using multiple qualifiers for test-cases
in MyFaces CODI and stumbled upon the following scenario, which is not
totally clear to me.
Image you have the following producer methods:
�...@produces
�...@qualifier2
�...@applicationscoped
public ProducerBean createWithQualifier2()
{
return new ProducerBean();
}
�...@produces
�...@qualifier1
�...@qualifier2
�...@applicationscoped
public ProducerBean createWithQualifier1And2()
{
return new ProducerBean();
}
and you want to inject the instances produced by these producers. Now
you can use @Inject @Qualifier1 or @Inject @Qualifier1 @Qualifier2,
but when using @Inject @Qualifier2 you will get an exception, because
the injection point is ambiguous (both producers provide @Qualifier2).
However I was wondering if this is really unresolvable ambiguous,
because if you think about it, it would make sence to take the
producer createWithQualifier2() in this scenario (because the other
one provides additional qualifiers).
I also took a look in the CDI spec about this, but could only find the
following from section 2.3.4: A bean may only be injected to an
injection point if it has all the qualifiers of the injection point.
Of course this applies to both producers and thus, yes, it's kinda
ambiguous.
WDYT?
Regards,
Jakob
--
Jakob Korherr
blog: http://www.jakobk.com
twitter: http://twitter.com/jakobkorherr
work: http://www.irian.at
