[weld-issues] [JBoss JIRA] Commented: (WELD-904) Observer method inheritance broken

[Pete Muir (JIRA)]

    [ https://issues.jboss.org/browse/WELD-904?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12601292#comment-12601292 ] 

Pete Muir commented on WELD-904:
--------------------------------

To answer your point about why the confusion - this area of the spec received heavy editing just before the spec was submitted (in an ideal world there would be a period during which the spec is not changed to allow the TCK to catch up, this didn't happen in this case) so quite a few resources were out of date and it took a while to get it correct.

> Observer method inheritance broken
> ----------------------------------
>
>                 Key: WELD-904
>                 URL: https://issues.jboss.org/browse/WELD-904
>             Project: Weld
>          Issue Type: Bug
>          Components: Events
>    Affects Versions: 1.1.1.Final
>            Reporter: Christian Bauer
>            Priority: Minor
>
> {code}
> /*
> <beans xmlns="http://java.sun.com/xml/ns/javaee"
>        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">
>     <alternatives>
>         <class>Foo$Bar</class>
>     </alternatives>
> </beans>
>  */
> @ApplicationScoped
> public class Foo {
>     public static void main(String[] args) {
>         WeldContainer weld = new Weld().initialize();
>         weld.event().select(MyEvent.class).fire(new MyEvent());
>     }
>     static class MyEvent {
>     }
>     @Qualifier
>     @Target({FIELD, PARAMETER})
>     @Retention(RUNTIME)
>     public @interface SomeQualifier {
>     }
>     @PostConstruct
>     void init() {
>         System.out.println("INIT FOO");
>     }
>     void onEvent(@Observes MyEvent e) {
>         System.out.println("EVENT FOO");
>     }
>     @Alternative
>     @Specializes
>     static public class Bar extends Foo {
>         @Override
>         void init() {
>             System.out.println("INIT BAR");
>         }
>         @Override
>         void onEvent(@Observes @SomeQualifier MyEvent e) {
>             System.out.println("EVENT BAR");
>         }
>     }
> }
> {code}
> The expected output is:
> INIT BAR
> The actual output is:
> INIT BAR
> EVENT BAR
> Removing the @SomeQualifier annotation on the Bar#onEvent() method results in:
> INIT BAR
> EVENT BAR
> EVENT BAR
> Removing also the @Observes annotation on the Bar#onEvent() method results in:
> INIT BAR
> EVENT BAR
> One or several of these outcomes is wrong. Also, section 4.2 of the spec says that observer methods are only inherited if the subclass doesn't override the method. I'm confused why everyone (e.g. https://issues.jboss.org/browse/CDITCK-186) seems to assume the exact opposite.

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