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javaspringaopspring-aop

Pointcut for annotated methods or methods in annotated classes


I need a pointcut for methods in classes annotated with @X or methods annotated with @X. I also need the annotation object. If both the class and the method are annotated I prefer to get the method annotation as argument.

I tried the following, which creates an "inconsistent binding" warning. (Why not just set them null?)

@Around("@annotation(methodLevelX) || @within(classLevelX)")
public Object advise(ProceedingJoinPoint pjp, X methodLevelX, X classLevelX)

The following creates a "ambiguous binding of parameter(s) x across '||' in pointcut" warning. (Which does not necessarily make sense in my opinion: Why not bind the first short circuited evaluation?)

@Around("@annotation(x) || @within(x)")
public Object advise(ProceedingJoinPoint pjp, X x)

Splitting the previous attempt in two naturally results in two method calls if class and method annotations are present.

I know I could just get the method and class with reflection and my desired annotation with a pointcut like this:

@Around("@annotation(com.package.X) || @within(com.package.X)")

But I'd prefer not to.

Is there any "one pointcut, one method, one annotation argument", solution for my requirement that does not require reflection?


Solution

  • Not quite, but almost. You will need two pointcuts, two advices, but you can delegate the work to a single method. Here's how it would look like:

    @Aspect
    public class AnyAspectName {
    
        @Pointcut("execution(@X * *.*(..))")
        void annotatedMethod() {}
    
        @Pointcut("execution(* (@X *).*(..))")
        void methodOfAnnotatedClass() {}
    
        @Around("annotatedMethod() && @annotation(methodLevelX)")
        public Object adviseAnnotatedMethods(ProceedingJoinPoint pjp, X methodLevelX) 
                throws Throwable {
            return aroundImplementation(pjp, methodLevelX);
        }
    
        @Around("methodOfAnnotatedClass() && !annotatedMethod() && @within(classLevelX)")
        public Object adviseMethodsOfAnnotatedClass(ProceedingJoinPoint pjp, X classLevelX) 
                throws Throwable {
            return aroundImplementation(pjp, classLevelX);
        }
    
        public Object aroundImplementation(ProceedingJoinPoint pjp, X annotation) 
                throws Throwable {
            return pjp.proceed();
        }
    
    }
    

    Note that besides splitting apart the @annotation() and @within() pointcuts, I added restrictions to the resulting pointcuts so that they aren't too broad. I suppose you want method execution join points, so I added the needed pointcut expressions that would restrict it to method execution. They are matching

    1. execution of any method annotated with @X with any return type in any class being in any package for the first advice
    2. execution of any method with any return type in any class annotated with @X for the second.

    Further restricting @within(X) and @annotation(X) comes in handy, because @within(X) by itself would match

    any join point where the associated code is defined in a type with an annotation of type X

    which would include method-execution, method-call, constructor-execution, constructor-call, pre-initialization, static initialization, initialization, field set, field get, exception-handler, lock type join points (not all join points are valid for around advices though). Similarly, @annotation(X) by itself would mean

    any join point where the subject has an annotation of type X

    which could also mean most of the previously mentioned join points, depending on the target type of your annotation.