Using an abstract method to assign an annotion property

Question

Hi Guys
I have an annotation for specifiying that a method requires a transation. It's very simple, and looks like this:
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface TransationRequired
    PersistenceUnitDescriptor persistenceUnitDescriptor();
}PersistenceUnitDescriptor is a simple enum, and I use Aspect J to weave code around methods annotated with this annotation.
When I annotate a method like this
@TransationRequired(persistenceUnitDescriptor = PersistenceUnitDescriptor.XXX)
     public Boolean func(String xx)
         //TODO: Something
     }It works fine, but when I annotate like this :
@TransationRequired(persistenceUnitDescriptor = getPersistenceUnit())
     public Boolean func(String xx)
         //TODO: Something
     }the apect code is never run.
getPersistenceUnit() is an abstract method and it is the only thing which is different between the two cases.
I'm not sure if this is beacuse of the annotation or because the weaving, but I thought I would ask in the annotation categroy just in case.
Anyone got an idea as to what may be causing this?
Thanks in advance,
Vackar

Answer 1

VackarAfzal wrote:
OK, Thanks for the tip. Pity that it has to be constant, in my opinion annotations would be a lot more powerful if you could dynamically change attributes. That really would make them more than just an alternative to annoying config files. But perhaps there are some technical details that I'm not aware of which makes this idea seem silly.Annotations were designed as a compile-time construct so the values within need to be compile time constants. At runtime, dynamic proxies are used to construct objects whose methods will return the values in question. You are free to construct your own objects implementing the interface of an annotation type at runtime that return values determined more dynamically.