The CDI 4.0 spec says in section 2.8.1 ( https://jakarta.ee/specifications/cdi/4.0/jakarta-cdi-spec-4.0#event_type... ): "Any Java type may be an observed event type." That means I can do this: private void primitive(@Observes int i) { // any type, including int, can be an observed event type System.out.println("primitive: " + i); } And this: private void wrapper(@Observes Integer i) { System.out.println("wrapper: " + i); } Then of course the only way to fire an event is by using the Event object and specifying the type of even you want to fire as its sole type argument: // for example @Inject private Event<Integer> e; (Type arguments of course cannot be primitive.) No mention in the specification's section on observer resolution talks about primitive types and/or wrapper types and how they interact. (Obviously there are unrelated sections regarding typesafe resolution in the context of dependency injection that do talk about this, but they do not seem to apply here without a biiiiiig stretch (observed event parameters are not injection points; event types are not bean types).) If I do e.fire(Integer.valueOf(42)), the primitive(int) observer method above is called (in Weld 5.1.3.Final). So is the wrapper(Integer) observer method. This certainly is convenient and I'm kind of glad it works that way, but is it correct? Is it a Weld value-add? Or should the spec have said something about interoperability of primitives and wrapper types in observer resolution? Best, Laird _______________________________________________ weld-dev mailing list -- weld-dev(a)lists.jboss.org To unsubscribe send an email to weld-dev-leave(a)lists.jboss.org Privacy Statement: https://www.redhat.com/en/about/privacy-policy List Archives: https://lists.jboss.org/archives/list/weld-dev@lists.jboss.org/message/ID...

I think that it makes a lot of sense to follow the rules from type-safe resolution here, i.e. https://jakarta.ee/specifications/cdi/4.1/jakarta-cdi-spec-4.1#primitive_... . Martin On 17. 10. 24 9:39, Matej Novotny wrote: > Hello, > > this is a good candidate for spec issue. I've created one - > https://github.com/jakartaee/cdi/issues/829 > <https://github.com/jakartaee/cdi/issues/829> > My personal take is that Weld behavior is a way to go as otherwise you'd > have no use for observing primitive types. > Strictly speaking, it is ATM Weld value-add but I don't see why the spec > couldn't cover this or at least have some TCK for it (I found none). > > Matej > > On Thu, Oct 17, 2024 at 4:06 AM Laird Nelson <ljnelson(a)gmail.com > <mailto:ljnelson@gmail.com>> wrote: > > The CDI 4.0 spec says in section 2.8.1 > ( https://jakarta.ee/specifications/cdi/4.0/jakarta-cdi-spec-4.0#event_type... < https://jakarta.ee/specifications/cdi/4.0/jakarta-cdi-spec-4.0#event_type... >): > > "Any Java type may be an observed event type." > > That means I can do this: > > private void primitive(@Observes int i) { // any type, including > int, can be an observed event type > System.out.println("primitive: " + i); > } > > And this: > > private void wrapper(@Observes Integer i) { > System.out.println("wrapper: " + i); > } > > Then of course the only way to fire an event is by using the Event > object and specifying the type of even you want to fire as its sole > type argument: > > // for example > @Inject > private Event<Integer> e; > > (Type arguments of course cannot be primitive.) > > No mention in the specification's section on observer resolution > talks about primitive types and/or wrapper types and how they > interact. (Obviously there are unrelated sections regarding typesafe > resolution in the context of dependency injection that do talk about > this, but they do not seem to apply here without a biiiiiig stretch > (observed event parameters are not injection points; event types are > not bean types).) > > If I do e.fire(Integer.valueOf(42)), the primitive(int) observer > method above is called (in Weld 5.1.3.Final). So is the > wrapper(Integer) observer method. This certainly is convenient and > I'm kind of glad it works that way, but is it correct? Is it a Weld > value-add? Or should the spec have said something about > interoperability of primitives and wrapper types in observer resolution? > > Best, > Laird > _______________________________________________ > weld-dev mailing list -- weld-dev(a)lists.jboss.org > <mailto:weld-dev@lists.jboss.org> > To unsubscribe send an email to weld-dev-leave(a)lists.jboss.org > <mailto:weld-dev-leave@lists.jboss.org> > Privacy Statement: https://www.redhat.com/en/about/privacy-policy > <https://www.redhat.com/en/about/privacy-policy> > List Archives: > https://lists.jboss.org/archives/list/weld-dev@lists.jboss.org/message/ID... < https://lists.jboss.org/archives/list/weld-dev@lists.jboss.org/message/ID... > > > > _______________________________________________ > weld-dev mailing list -- weld-dev(a)lists.jboss.org > To unsubscribe send an email to weld-dev-leave(a)lists.jboss.org > Privacy Statement: https://www.redhat.com/en/about/privacy-policy > List Archives: https://lists.jboss.org/archives/list/weld-dev@lists.jboss.org/message/FZ... -- Martin Kouba Principal Software Engineer Red Hat, Czech Republic