Capturing advice execution (advising advice) in AspectJ

Question

I'm trying to capture the execution of an advice using annotation in Maven, but it says that advice has not been applied. Here is the code:

package testMaven8;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Around;


@Aspect
public class aspecter {

    public static int a;

    public void setA(int a) {
        this.a = a;
    }

    public int getA() {
        return a;
    }

    @Before("execution(*  testMaven8.das.qwe(..))")
    public void testBefore2(){
        System.out.println("yoo2");
        setA(102);
        System.out.println(a);
    }

    @Before("execution (* testMaven8.aspecter.testBefore2(..))")
    public void advice1(){
        System.out.println("advicing advice testBefore2");
    }

}

Is there something wrong with the code? I'm trying to avoid the usage of Aspect class if it's possible. Any help is appreciated.

Thanks

Answer 1

Advice execution is something special in AspectJ, not a normal method execution. Thus, if you want to capture advice execution you also need a special pointcut with the surprising name - adviceexecution() ;-)

Here is some sample code:

Driver application:

package de.scrum_master.app;

public class Application {
    public static void main(String[] args) {
        new Application().doSomething();
    }

    public void doSomething() {
        System.out.println("Doing something");
    }
}

Aspect capturing method executions:

package de.scrum_master.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class MethodInterceptor {
    @Before("execution(!static * *(..))")
    public void interceptMethod(JoinPoint thisJoinPoint) {
        System.out.println(thisJoinPoint);
    }
}

Aspect capturing advice executions:

package de.scrum_master.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;

@Aspect
public class AdviceInterceptor {
    @Before("!within(AdviceInterceptor) && adviceexecution()")
    public void interceptAdvice(JoinPoint thisJoinPoint) {
        System.out.println(thisJoinPoint);
    }
}

Please do not try to pack the advice execution interceptor into the same aspect as another advice because you can easily end up in an endless recursion if you cannot exclude the adviceexecution() pointcut from capturing itself via !within(AdviceInterceptor).

Console log:

adviceexecution(void de.scrum_master.aspect.MethodInterceptor.interceptMethod(JoinPoint))
execution(void de.scrum_master.app.Application.doSomething())
Doing something