Session bean inheritance

[gus888]

Hi All,

I want to whether it is possible to use inheritance in session beans as follows:

public interface BaseInterface {
 public boolean isNew();

 public void destroy();
}

@Local
public interface ProjectEditor extends BaseInterface {
 ...
 //other business logic
}

public class BaseBean implements BaseInterface {

 @In(create=true)
 private EntityManager entityManager;

 @TransactionAttribute(NOT_SUPPORTED)
 public boolean isNew() {
 return isNew;
 }

 @Destroy @Remove
 public void destroy() {}

}



@Name("projectEditor")
@Stateful
public class ProjectEditorBean extends BaseBean implements ProjectEditor {
 ...
 //other business logic
}

Thank you in advance for any guidance!
Gus

[bfo81]

I think so. Have a look at the "avoiding DRY" thread ;).

[gus888]

Thank you VERY MUCH, bfo81. The "avoiding DRY" is great topic.

[bfo81]

Yes, it is :). Just one more thing:

There are annotations that can be used in abstract superclasses (like @PersistenceContext, @In, @Out, @Logger, @Begin, @End, @Remove, @Destroy...) and there are some that must be applied to the concrete subclasses (@Stateful, @Stateless, @Name (of course *g*), @Conversational, @Scope, ...).

I'm not 100% sure, but I think that you can annotate the methods and properties of a superclass but not the class itself. But as I said, I'm not absolutely sure about that. Maybe someone with a deeper insight into the things going on can tell as a simple rule regarding this ;).

[gavin.king]

Any annotation on a superclass _member_ should be inherited to the subclass. Annotations on the superclass _type_ are not, in general.

[gus888]

BFO81, thank you so much for the excellent detailed explanation.

Gavin, thank you so much for your OFFICIAL confirmation.