java - How to instrument / advice a Spring Data (JPA) repository?

Question

I'm failing in my effort to advice a spring data jpa repository. The goal is to instrument (around) all non-void public methods in a particular repository annotated with a custom annotation (ResourceNotFound in this example) and throw an exception when the return value is either null or an empty collection.

@Repository 
@ResourceNotFound
@Transactional(readOnly = true)
public interface CityRepository extends JpaRepository<City, Long>, JpaSpecificationExecutor<City> { … }

The following advice is to wire all public methods of the implementations of the interface annotated with @ResourceNotFound.

@Pointcut("within(com.digitalmisfits.spring.aop.annotation.ResourceNotFound *)")
public void beanAnnotatedWithResourceNotFound() {}

@Pointcut("execution(public * *(..))")
public void publicMethod() {}

@Around("beanAnnotatedWithResourceNotFound() && publicMethod()")
public Object publicMethodInsideAClassMarkedWithResourceNotFound(ProceedingJoinPoint pjp) throws Throwable {

    System.out.println("publicMethodInsideAClassMarkedWithResourceNotFound " + pjp.getTarget().toString());;

    Object retVal =  pjp.proceed();

    if(((MethodSignature) pjp.getSignature()).getReturnType() != Void.TYPE && isObjectEmpty(retVal))
        throw new RuntimeException("isObjectEmpty == true");

    return retVal;
}

The publicMethodInsideAClassMarkedWithResourceNotFound(…) method works when the pointcut isspecified as:

@Pointcut("execution(public * package.CityRepository+.*(..))")

However, the @ResourceNotFound annotation is not being picked up. This might be due to the fact that the underlying class of the repository interface is a (proxied) SimpleJpaRepository which does not have that particular annotation.

Is there a way to propagate @ResourceNotFound to the implementation?

-- update --

Changed the question to reflect the fact that the advice (around) only should apply to repositories with a custom annotation.

Answer 1

If you want to intercept the repository call on the repository level, you don't actually need to introduce a custom annotation for that. You should be able to get this working with a plain type match:

 @Pointcut("execution(public !void org.springframework.data.repository.Repository+.*(..))")

This will intercept the execution of all non-void methods of all Spring beans that extend the Spring Data Repository interface.

A slightly related example can be found in the Spring Data examples repository.