[cdi-dev] Getting injection point from Bean#create

[Martin Kouba]

Hi Arjan,

yep, the behavior changed because of fix for WELD-1823 [1]. The spec 
(6.5.3. Contextual reference for a bean) requires to inject a null value 
if a dependent object is not being injected into any injection point. 
I'm not sure we can distinguish these different types of usage of 
BeanManager.getReference().

By the way, Tomas tested the original way using 
BeanManager.getInjectableReference() and it works fine. For the purpose 
of this use case a custom IP with InjectionPoint as a requested type, 
@Default as a qualifier and "this" as a declaring bean should be enough 
(no need for InjectionPointGenerator).

We're going to add a test in the Weld test suite. I don't think we 
should add this into TCK as it's rather corner case not clearly defined 
in the spec.

Martin

[1]
https://issues.jboss.org/browse/WELD-1823

Dne 27.1.2016 v 15:20 Tomas Remes napsal(a):
>
> Hi Arjan,
>
> Ok I am going to check this. Wrt TCK I am not sure it's suitable to some spec assertion so I wouldn't add it to TCK but we can definitely include this to Weld internal testsuite.
>
> Thank's
>
> Tom
>
> ----- Original Message -----
> From: "arjan tijms" <arjan.tijms at gmail.com>
> To: "Jozef Hartinger" <jharting at redhat.com>
> Cc: cdi-dev at lists.jboss.org
> Sent: Wednesday, January 27, 2016 2:42:00 PM
> Subject: Re: [cdi-dev] Getting injection point from Bean#create
>
> Hi
>
> On Thu, Nov 20, 2014 at 9:42 PM, Jozef Hartinger < jharting at redhat.com > wrote:
>
>
> The simplest thing you can do is:
>
> Bean<InjectionPoint> bean = (Bean<InjectionPoint>) manager.resolve(manager.getBeans(InjectionPoint.class));
> InjectionPoint ip = (InjectionPoint) manager.getReference(bean, InjectionPoint.class, manager.createCreationalContext(bean));
>
> I just tried this again, and unfortunately it now fails on Weld.
>
> I quickly tried a series of Weld versions and this is the result:
>
> Weld
> 2.2.6 works
> 2.2.8 works
> 2.2.9 fails
> 2.2.13 fails
> 2.2.14 fails
> 2.2.16 fails
> 2.3.0 fails
> 2.3.2 fails
>
> So apparently it broke between 2.2.8 and 2.2.9.
>
> Would it be possible to add a TCK test for this? This would be really helpful as we'd like to use this for the JSF 2.3 RI.
>
> Kind regards,
> Arjan Tijms
>
>
>
>
>
>
>
>
>
>
> On 11/19/2014 05:06 PM, arjan tijms wrote:
>
>
>
> Hi,
>
> In a producer method it's trivial to get access to an InjectionPoint
> instance representing the point where the value produced by the
> producer will be injected.
>
> When registering a Bean manually from an extension using
> AfterBeanDiscovery#addBean, this is not immediately obvious.
>
> After some fumbling with the CDI APIs I came up with the following
> code that seems to work on both Weld and OWB (didn't test CanDI yet).
>
> It uses a small "dummy" class, which is used to grab an InjectionPoint off:
>
> In a Bean:
>
> public Object create(CreationalContext<Object> creationalContext) {
>
> InjectionPoint injectionPoint = (InjectionPoint)
> beanManager.getInjectableReference(
> resolve(beanManager,
> InjectionPointGenerator.class).getInjectionPoints().iterator().next(),
> creationalContext
> );
>
> With InjectionPointGenerator being the following class:
>
> public class InjectionPointGenerator {
> @Inject
> private InjectionPoint injectionPoint;
> }
>
> And resolve being the following method:
>
> public static <T> Bean<T> resolve(BeanManager beanManager, Class<T> beanClass) {
> Set<Bean<?>> beans = beanManager.getBeans(beanClass);
>
> for (Bean<?> bean : beans) {
> if (bean.getBeanClass() == beanClass) {
> return (Bean<T>)
> beanManager.resolve(Collections.<Bean<?>>singleton(bean));
> }
> }
>
> return (Bean<T>) beanManager.resolve(beans);
> }
>
> As mentioned, while this seems to work, I wonder if it's the best approach.
>
> Kind regards,
> Arjan
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-- 
Martin Kouba
Software Engineer
Red Hat, Czech Republic