2:13 a.m.
What Arne was concerned about is that we cannot inject the same instance
into two different typed injection points. We can't have an object that
is a list of strings and a list of integers at the same time. We would
need such an object if we wanted to inject it into both @Inject
List<String> and @Inject List<Integer>.
What I pointed out is that CDI has this covered, as it requires all
beans with a parameterized bean class to be dependent scoped and by
definition not sharable across multiple injection points. CDI will
create a _new instance_ for each injection point, therefore it actually
can inject bean MyClass<T> into both @Inject MyClass<String> and @Inject
MyClass<Integer>, since it injects two different instances. There is no
need to have a custom extension and register MyClass<T> multiple times
(as MyClass<String>, MyClass<Integer>, etc.).
So this means the change at [1] was a mistake.
[1]
https://github.com/cdi-spec/cdi/commit/b32243350ace6a0bba337f91a35f5fd05c...
Marko
On 16.7.2013 7:17, Romain Manni-Bucau wrote:
Hmm not sure i get the Dependent limit. Using a custom extension
you'll register the same bean as many times as needed but using
different values for parameters and the scope you want.
Why CDI wouldnt be able of it out of the box?
It is really something basic in 2013 and find really sad that's look
so complicated. Please explain me what i'm missing if so.
Le 16 juil. 2013 00:15, "Marko Lukša" <marko.luksa(a)gmail.com
<mailto:marko.luksa@gmail.com>> a écrit :
Actually, it will never be the same instance, since all beans with
a parameterized bean class must be @Dependent scoped.
Marko
On 15.7.2013 23:46, Arne Limburg wrote:
> No, I understood you right ;-)
> In Java the same instance cannot be MyClass<String> and
> MyClass<Integer> at the same time.
> We would do exactly that, if we had two injection points like
> @Inject
> MyClass<String> myStringClass;
> @Inject
> MyClass<Integer> myIntegerClass;
> In plain java this could never be the same instances without
> heavy (compile-time) casting, thus this should not be the same
> instances in CDI.
>
> Cheers,
> Arne
>
> Von: Romain Manni-Bucau <rmannibucau(a)gmail.com
> <mailto:rmannibucau@gmail.com>>
> Datum: Montag, 15. Juli 2013 23:41
> An: Arne Limburg <arne.limburg(a)openknowledge.de
> <mailto:arne.limburg@openknowledge.de>>
> Cc: Mark Struberg <struberg(a)yahoo.de <mailto:struberg@yahoo.de>>,
> Martin Kouba <mkouba(a)redhat.com <mailto:mkouba@redhat.com>>,
> "cdi-dev(a)lists.jboss.org <mailto:cdi-dev@lists.jboss.org>"
> <cdi-dev(a)lists.jboss.org <mailto:cdi-dev@lists.jboss.org>>
> Betreff: Re: [cdi-dev] CDI and generics
>
> hmm think you misunderstood what i said (sorry if it was unclear)
>
> basically my point was a generic bean or produced bean should be
> injectable everywhere so MyClass<T> should match @Inject
> MyClass<String>. In plain java we do: new MyClass<String>().
>
> /Romain Manni-Bucau/
> /Twitter: @rmannibucau <https://twitter.com/rmannibucau>/
> /Blog: //http://rmannibucau.wordpress.com//
> /LinkedIn: //_http://fr.linkedin.com/in/rmannibucau_/
> /Github: https://github.com/rmannibucau/
>
>
>
> 2013/7/15 Arne Limburg <arne.limburg(a)openknowledge.de
> <mailto:arne.limburg@openknowledge.de>>
>
> Hi Romain,
>
> In plain old java the behavior would depend on where the type
> variable is declared.
> See the following samples:
>
> public class MyClass<T> {
>
> List<T> myList = new ArrayList<T>();
>
> List<String> myStringList = myList;
> }
>
> public class MyClass {
>
> <T> List<T> myList() {
> return new ArrayList<T>();
> }
>
> List<String> myStringList = myList();
> }
>
> The first example does not work and the second works.
>
> And even, if you would access myList from outside, the first
> example just works, if you instantiate myClass with the type
> argument:
>
> List<String> myStringList = new MyClass<String>().myList;
>
> To transfer this to CDI: We would need an instance of Bean
> MyClass with MyClass<String> in the type closure. And we
> would have to do this for every type argument that can be
> found within the injection points, i.e., if we had the
> injection points
> @Inject
> MyClass<String> myStringClass;
> @Inject
> MyClass<Integer> myIntegerClass;
> either the type closure of my class would have to contain
> MyClass<String> AND MyClass<Integer> or we would need to have
> different beans for both types. I think, we cannot do either.
>
> I suggest to handle TypeVariables declared at class level
> different than TypeVariables declared at (producer-)method
> level. Thus we could handle Mark Strubergs case and leave the
> rest like it is in plain old java.
>
> I suggest to change the fourth bullet point of chapter 5.2.4:
> "the required type parameter is an actual type, the bean type
> parameter is a type variable that is declared at class level
> and the actual type is assignable from the upper bound of the
> type variable,"
> and add another bullet point:
> "the required type parameter is an actual type, the bean type
> parameter is a type variable that is declared at method level
> and the actual type is assignable to the upper bound of the
> type variable, or"
> And add a footnote: "If no explicit upper bound is defined,
> the implicit upper bound java.lang.Object is assumed"
>
> BTW. Should we create a spec issue for that?
>
> WDYT?
> Regards,
> Arne
>
> P.S.: I don't think this is a backward compatibility issue,
> just because Weld and OpenWebBeans implemented it differently
> in the past. It just was not clear in 1.0 and is not in 1.1.
> The misleading part is the "if any" in the fourth bullet
> point. A TypeVariable ALWAYS has an upper bound. "If no bound
> is given for a type variable, Object is assumed" (Java Lang
> Spec 4.4)
>
> Von: Romain Manni-Bucau <rmannibucau(a)gmail.com
> <mailto:rmannibucau@gmail.com>>
> Datum: Montag, 15. Juli 2013 07:55
> An: Mark Struberg <struberg(a)yahoo.de <mailto:struberg@yahoo.de>>
> Cc: Martin Kouba <mkouba(a)redhat.com
> <mailto:mkouba@redhat.com>>, Arne Limburg
> <arne.limburg(a)openknowledge.de
> <mailto:arne.limburg@openknowledge.de>>,
> "cdi-dev(a)lists.jboss.org <mailto:cdi-dev@lists.jboss.org>"
> <cdi-dev(a)lists.jboss.org <mailto:cdi-dev@lists.jboss.org>>
> Betreff: Re: [cdi-dev] CDI and generics
>
> +1, if we are no more aligned on something so simple in plain
> java we are useless i fear :(
>
> (i used and saw it used in a lot of real apps)
>
>
> /Romain Manni-Bucau/
> /Twitter: @rmannibucau <https://twitter.com/rmannibucau>/
> /Blog: //http://rmannibucau.wordpress.com//
> /LinkedIn: //_http://fr.linkedin.com/in/rmannibucau_/
> /Github: https://github.com/rmannibucau/
>
>
>
> 2013/7/14 Mark Struberg <struberg(a)yahoo.de
> <mailto:struberg@yahoo.de>>
>
> folks, this breaks backward compatibility
>
>
> In CDI 1.0 it was perfectly fine to do the following
>
> @Produces
> @Dependent
> public <KEY, VALUE extends Serializable> Cache<KEY,
> VALUE> getDefaultCache(InjectionPoint injectionPoint) {
> Type ipType = injectionPoint.getType();
> String cacheName = null;
>
> if (ipType instanceof ParameterizedType) {
> ParameterizedType generic =
> (ParameterizedType) ipType;
> Type[] paramTypes =
> generic.getActualTypeArguments();
> if (paramTypes == null || paramTypes.length
> != 2) {
> throw new RuntimeException("illegal param
> types for generic type " + ipType);
> }
>
> if (paramTypes[1] instanceof Class) {
> cacheName = ((Class)
> paramTypes[1]).getSimpleName();
> }
> else {
> cacheName = paramTypes[1].toString();
> }
> }
>
> return getCache(cacheName);
> }
>
>
>
> usage:
>
>
> @Inject
> private Cache<String, IdmUser> userCache;
>
>
> With your new interpretation you basically trash this, right?
> For having a generic producer you would need to create a
> distinct producer method for each and every usage. This
> just doesn't work out in practice...
>
>
>
> LieGrue,
> strub
>
>
>
>
>
> ----- Original Message -----
> From: Martin Kouba <mkouba(a)redhat.com
> <mailto:mkouba@redhat.com>>
> To: Arne Limburg <arne.limburg(a)openknowledge.de
> <mailto:arne.limburg@openknowledge.de>>
> Cc: "cdi-dev(a)lists.jboss.org
> <mailto:cdi-dev@lists.jboss.org>"
> <cdi-dev(a)lists.jboss.org <mailto:cdi-dev@lists.jboss.org>>
> Sent: Wednesday, 10 July 2013, 14:01
> Subject: Re: [cdi-dev] CDI and generics
>
> No, it's not necessary. We'll fix this within CDITCK-349
> [1]. Leave a
> comment if you wish :-)
>
> Thanks
> Martin
>
> [1]
> https://issues.jboss.org/browse/CDITCK-349
>
>
> Dne 10.7.2013 13:52, Arne Limburg napsal(a):
> > OK, so shall I create a TCK issue for that?
> >
> >
> > Cheers,
> > Arne
> >
> > Am 10.07.13 13:50 schrieb "Martin Kouba" unter
> <mkouba(a)redhat.com <mailto:mkouba@redhat.com>>:
> >
> >> Hi Arne,
> >>
> >> I think so (except the required type is
> Baz<List<Qux>>) - there is no
> >> bean with assignable bean type for this IP (according
> to CDI 1.1 rules
> >> of course).
> >>
> >> Martin
> >>
> >> Dne 10.7.2013 13:16, Arne Limburg napsal(a):
> >>> 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(a)redhat.com <mailto:mkouba@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/b32243350ace6a0bba337f91a35f5fd0
> >>>>> 5c
> >>>>> 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.MemberLevelInheritanceTes
> >>>>>> t
> >>>>>> 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(a)lists.jboss.org
> <mailto:cdi-dev@lists.jboss.org>
> >>>>>>
https://lists.jboss.org/mailman/listinfo/cdi-dev
> >>>>>
> >>>>>
> >>>>>
> >>>>> _______________________________________________
> >>>>> cdi-dev mailing list
> >>>>> cdi-dev(a)lists.jboss.org
> <mailto:cdi-dev@lists.jboss.org>
> >>>>> https://lists.jboss.org/mailman/listinfo/cdi-dev
> >>>>>
> >>>> _______________________________________________
> >>>> cdi-dev mailing list
> >>>> cdi-dev(a)lists.jboss.org
<mailto:cdi-dev@lists.jboss.org>
> >>>> https://lists.jboss.org/mailman/listinfo/cdi-dev
> >>>
> >
>
> _______________________________________________
> cdi-dev mailing list
> cdi-dev(a)lists.jboss.org <mailto:cdi-dev@lists.jboss.org>
> https://lists.jboss.org/mailman/listinfo/cdi-dev
>
> _______________________________________________
> cdi-dev mailing list
> cdi-dev(a)lists.jboss.org <mailto:cdi-dev@lists.jboss.org>
> https://lists.jboss.org/mailman/listinfo/cdi-dev
>
>
>
>
>
> _______________________________________________
> cdi-dev mailing list
> cdi-dev(a)lists.jboss.org <mailto:cdi-dev@lists.jboss.org>
> https://lists.jboss.org/mailman/listinfo/cdi-dev
_______________________________________________
cdi-dev mailing list
cdi-dev(a)lists.jboss.org <mailto:cdi-dev@lists.jboss.org>
https://lists.jboss.org/mailman/listinfo/cdi-dev