When to use @Pointcut & @Before, @After AOP Annotations

Question

Am learning AOP concepts in Spring. I am now pretty aware of the usages of @Before and @After Annotations and started using it for Time capturing purpose.

This is pretty much satisfying all my AOP related needs. Wondering what is that @pointcut annotation that every spring guide talks about ? Is that a redundant functionality ? or does it has separate needs ?

Answer 1

In simple words whatever you specify inside @Before or @After is a pointcut expression. This can be extracted out into a separate method using @Pointcut annotation for better understanding, modularity and better control. For example

    @Pointcut("@annotation(org.springframework.web.bind.annotation.RequestMapping)")
    public void requestMapping() {}

    @Pointcut("within(blah.blah.controller.*) || within(blah.blah.aspect.*)")
    public void myController() {}

    @Around("requestMapping() && myController()")
    public Object logAround(ProceedingJoinPoint joinPoint) throws Throwable {
      ...............
   }  

As you can see instead of specifying the pointcut expressions inside @Around, you can separate it to two methods using @Pointcut.