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Re: [aspectj-users] @Entity but not subclass of @Entity 
Hi Andy,
I think I didn't explain it clearly. I have

@Entity
public class Bean {

}

and a number of sub-beans :

@Entity
public class SubBean extends Bean {

}

How can I match Bean but not SubBean based on the @Entity annotation? That is, how can I write "A class annotated with @Entity which is NOT a subclass of another class annotated with @Entity".

Since the only "subclass" operator in AspectJ is the "+", which is inclusive, writing (@Entity *) && !((@Entity *)+) is useless, as it would be using an interface instead of (@Entity *).

If I had a construct to say "only subclasses" (suppose #, merely for illustrative purposes) I could write:
- (@Entity *) && ((@Entity *)#) to find only those entities which super class is also an entity
- (@Entity *) && !((@Entity *)#) to find only those classes which are entities but does not extend another entity
- (Bean) && !(Bean#), as a slower alternative to within(Bean).

Such an operator is not present cause it is (nearly) useless when only classes and interfaces are used, because :
- They are always inherited, as opposed to annotations
- Declaring an interface on a class and on one or more of its subclasses is (nearly) useless and has no strange side effects.
- Taking ITD methods with that interface would result in method overriding with same implementation, which is (usually) acceptable and invisible.

But annotations are more flexible from this point of view, and in this case I need a bit more flexibility.

Is there a way to emulate this?

The "if" pointcut could solve situations where we are advicing (if(!thisJoinPointStaticPart.getSignature().getDeclaringType().getSuperClass().hasAnnotation(Entity.class))) but not when we are declaring parents cause a TypePattern is required there, nor when we are declaring a warning cause "if" is not statically determinable.

Am I missing something relevant here?

Simone

Andy Clement wrote:
Just to mention a possibly existing bug in this area to do with annotation inheritance:

https://bugs.eclipse.org/bugs/show_bug.cgi?id=128664

Andy

2009/8/12 Simone Gianni <simoneg@xxxxxxxxxx <mailto:simoneg@xxxxxxxxxx>>

    Hi All,
    I have a problem. I add some methods to beans annotated with
    @Entity. Some @Entity extends other @Entity, with the result that
    methods are added to both types. I added a check to avoid adding
    them if they are already there (using !hasmethod(...)), but it
    works or does not work depending on the class loading sequence
    (which is IMHO a bug I'll write another mail about).

    Anyway, it could be easy to solve writing "Apply this to @Entity
    beans that does not subclass another @Entity bean", I tried
    writing "(@Entity *) && !((@Entity *)+)", but it does not work
    obviously. I also tried an if on thisJoinPointStaticPart, but it
    is not usable there.

    Is there a way to do it? Is there an "exclusive +" that matches
    subclasses but not also the base class? While it is handy to write
    execution(MyClass+ .....) to match both class and subclass, and
    while there is a way to select all subclasses when the class name
    is known, I can't find a way to do it with annotations.

    Simone

-- Simone Gianni CEO Semeru s.r.l. Apache Committer
http://www.simonegianni.it/

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Simone Gianni            CEO Semeru s.r.l.           Apache Committer
http://www.simonegianni.it/