An AnnotationProvider pipeline would provide two very nice features:
- The possibility of converting one annotation into another. This could easily allow for Tapestry-IoC recognize Spring or EJB or Guice dependency-injection annotations, for example.
- The possibility to easily add annotations to classes, fields and methods that do not have them. Example: use of JPA and Hibernate Validator annotations to provide BeanEditor/BeanEditForm validation without using @Validate on the entity classes. Maybe we need an specialized validation pipeline, as JPA annotations (@Column(nullable= false), for example) would add one validation rule, but Hibernate Validator (@Email) would provide another validation rule, not overwriting the first one.