Spring AOP: how to get the annotations of the adviced method

hugri picture hugri · Apr 1, 2010 · Viewed 14.9k times · Source

I'd like to implement declarative security with Spring/AOP and annotations. As you see in the next code sample I have the Restricted Annotations with the paramter "allowedRoles" for defining who is allowed to execute an adviced method.

    @Restricted(allowedRoles="jira-administrators")
        public void setPassword(...) throws UserMgmtException {             
               // set password code
               ...
        }

Now, the problem is that in my Advice I have no access to the defined Annotations:

public Object checkPermission(ProceedingJoinPoint pjp) throws Throwable {

    Signature signature = pjp.getSignature();
    System.out.println("Allowed:" + rolesAllowedForJoinPoint(pjp));
            ...
}

private Restricted rolesAllowedForJoinPoint(ProceedingJoinPoint thisJoinPoint)
        {
            MethodSignature methodSignature = (MethodSignature) thisJoinPoint.getSignature();
            Method targetMethod = methodSignature.getMethod();

            return targetMethod.getAnnotation(Restricted.class);
        }

The method above always returns null (there are no annotations found at all). Is there a simple solution to this?

I read something about using the AspectJ agent but I would prefer not to use this agent.

Answer

Oleg picture Oleg · Mar 9, 2011

To whoever is still having problem after changing annotation retention to Runtime, you might be having the same problem I had: getMethod() returns interface method instead of the implementing class. So, if you have your annotations in the class then naturally getAnnotations() on the interface method returns null.

The following solution solved this problem:

final String methodName = pjp.getSignature().getName();
final MethodSignature methodSignature = (MethodSignature)pjp.getSignature();
Method method = methodSignature.getMethod();
if (method.getDeclaringClass().isInterface()) {
    method = pjp.getTarget().getClass().getDeclaredMethod(methodName, method.getParameterTypes());    
}

and if you like, you have the option of handling interface annotations here too.

Some more comments available here: getting template method instance from ProceedingJoinPoint

Oleg