[cdi-dev] CDI and generics

Arne Limburg arne.limburg at openknowledge.de
Wed Jul 10 07:16:04 EDT 2013


Hi Martin,

So, which bean should be injected into
@Inject
    private Baz<List<T2>> t2BazList;
?

Baz<T> is also not assignable to Baz<List<String>>, because List<String>
is also not assignable from Object.


Am I right, that the test should throw an UnsatisfiedResolutionException?

Cheers,
Arne

Am 08.07.13 12:17 schrieb "Martin Kouba" unter <mkouba at redhat.com>:

>Re Arne's question:
>Yes, Baz is a managed bean and AmbiguousResolutionException should not
>be thrown because Qux is not a managed bean (doesn't have a public
>no-arg constructor).
>
>Re Marko's findings:
>Yes, the TCK assertions are not up to date and Baz<T> is not assignable
>to Baz<String>, because String is not assignable from Object (no bound
>is defined -> Object is assumed; see JSL 4.4). So I confirm a TCK issue.
>
>IMO this would deserve a proper cleanup...
>
>Martin
>
>Dne 8.7.2013 01:22, Marko Lukša napsal(a):
>> I'd say it's a bug. While Baz indeed is a managed bean, it shouldn't be
>> injected into injection point with type Baz<String> nor Baz<List<Qux>>.
>> So I believe you're right in saying that this test should fail with
>> UnsatisfiedResolutionException.
>> 
>> There was a change made to the spec way back in 2010 (see [1]), but the
>> TCK apparently wasn't updated then. I've filed an issue in the TCK jira
>> [2].
>> 
>> The problem isn't only in the TCK, but also in the spec itself. Some of
>> the examples in section 5.2.4 don't conform to the rules defined in the
>> same section (according to the rules, bean Dao<T extends Persistent>
>> shouldn't be eligible for injection into Dao<Order> or Dao<User>). I
>> remember asking about this a year ago ([3]), but I didn't articulate the
>> problem properly.
>> 
>> [1]
>> 
>>https://github.com/cdi-spec/cdi/commit/b32243350ace6a0bba337f91a35f5fd05c
>>151f14
>> [2] https://issues.jboss.org/browse/CDITCK-349
>> [3] http://lists.jboss.org/pipermail/cdi-dev/2012-April/001742.html
>> 
>> Marko
>> 
>> On 7.7.2013 16:04, Arne Limburg wrote:
>>> Hi all,
>>>
>>> At the OpenWebBeans list we are currently discussing handling of
>>> generics in CDI.
>>> I found a test in the CDI 1.1 TCK, which imho has a bug. The test
>>> is 
>>>org.jboss.cdi.tck.tests.inheritance.generics.MemberLevelInheritanceTest
>>> and the (simplified) deployment scenario is the following:
>>>
>>> public class Baz<T> {
>>> }
>>>
>>> public class Qux extends Baz<String> {
>>> }
>>>
>>> @Vetoed
>>> public class Bar<T1, T2> {
>>>   @Inject
>>>   private Baz<T1> baz;
>>>   @Inject
>>>   private Baz<List<T2>> t2BazList;
>>> }
>>>
>>> @RequestScoped
>>> public class Foo extends Bar<String, Qux> {
>>> }
>>>
>>> public class Producer {
>>>   @Produces
>>>   @Amazing
>>>   public String produceString() {
>>>     return "ok";
>>>   }
>>>
>>>   @Produces
>>>   public String[] produceStringArray() {
>>>     return new String[0];
>>>   }
>>>
>>>   @Produces
>>>   public Baz<Baz<Qux>> produceBazBazQux() {
>>>     return new Baz();
>>>   }
>>> }
>>>
>>> The class Bar has some more injection points, but that does not matter.
>>> Due to the TCK this deployment should work, but I don't know how.
>>> Question: Is Baz a Bean (I suppose so) and may it be injected into
>>> Bean Foo, more precisely into the second injection point of class Bar?
>>> - If yes, it also should be injected into the first injection
>>> point, right? This would lead to an AmbiguousResolutionException since
>>> Qux may also be injected into the first injection point.
>>> - If no, the deployment should fail with a
>>> UnsatisfiedResolutionException since there is no Bean that can be
>>> injected into that injection point.
>>>
>>> Is this a bug in the TCK and if not, how is this supposed to work?
>>>
>>> Cheers,
>>> Arne
>>>
>>>
>>> _______________________________________________
>>> cdi-dev mailing list
>>> cdi-dev at lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/cdi-dev
>> 
>> 
>> 
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