[cdi-dev] [JBoss JIRA] (CDI-248) Provide means to observe a group of qualified events ("Qualifier Inheritance"?)

Provide means to observe a group of qualified events ("Qualifier Inheritance"?) -------------------------------------------------------------------------------- Key: CDI-248 URL: https://issues.jboss.org/browse/CDI-248 Project: CDI Specification Issues Issue Type: Feature Request Components: Concepts, Events Reporter: Jens Schumann Fix For: TBD We have been using CDI events for application development quite extensively. For instance we use events to propagate entity lifecycle events (@Created/@Updated/@Deleted Customer customer) or GUI selections (@Selected/@Deselected Customer customer) and implement related business logic in event observers. (e.g. send email for newly created customers, clear cached values on select/deselect/create/update/delete ...). This works quite well, however we have noticed that especially our JSF Presentation Tier contains lots of observer methods implementing the same behavior for a group of related CDI events. Example: {code} public class XyzBean { public void onCustomerCreate(@Observes @Created Customer customer) { reset();} public void onCustomerUpdate(@Observes @Updated Customer customer) { reset();} public void onCustomerDelete(@Observes @Deleted Customer customer) { reset();} } {code} Looks ugly, doesn't it? The above example could be improved if CDI would be able to observe a group of qualified events, e.g. public void onCustomerLifeCycleEvent(@Observes @LifeCycleChange Customer customer) { reset(); } - ignore method and qualifier names for now. Since Java does not support annotation inheritance grouping could be achieved using "qualified qualifier annotations": {code} @Qualifier public @interface LifeCycleChange @Qualifier @LifeCycleChange public @interface Created @Qualifier @LifeCycleChange public @interface Updated @Qualifier @LifeCycleChange public @interface Deleted @Qualifier public @interface SelectionChange @Qualifier @SelectionChange public @interface Selected @Qualifier @SelectionChange public @interface Deselected {code} WDYT? Side effects? Problems?