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Spring AOP not working, when the method is called internally within a bean

Posted by: admin December 28, 2021 Leave a comment

Questions:

I have several Aspects coded in my application. All others works except for the following.

Service Interface

package com.enbiso.proj.estudo.system.service;
...
public interface MessageService {
     ...
     Message reply(Message message);
     Message send(Message message);
     ...
}

Service Implementation

package com.enbiso.proj.estudo.system.service.impl;
....
@Service("messageService")
public class MessageServiceImpl implements MessageService {
   ...
   @Override
   public Message reply(Message message) {
        ...
        return this.send(message);
   }

   @Override
   public Message send(Message message) {
         ...
   }
}

Aspect

@Aspect
@Component
public class NewMessageAspect {
    ...
    @AfterReturning(value = "execution(* com.enbiso.proj.estudo.system.service.impl.MessageServiceImpl.send(..))", 
                    returning = "message")
    public void perform(Message message){
       ...
    }
}

When I try to execute the send method the debug point is not getting hit in the aspect perform.

UPDATE

I did some investigations and found that this doesn’t work, when the send method is invoked from the reply method as below

@Autowire MessageService messageService;
...
messageService.reply(message);

But if I call the method messageService.send(message) it works fine. But as reply method is calling send method internally, shouldn’t it also invoke the aspect?

I have no idea what i have done wrong. Please help me.

Answers:

Thank you jst for clearing the things up. Just for the information purposes for the future developer in SO, I’m posting the full answer to this question


Lets assume that there is a bean from SimplePojo

public class SimplePojo implements Pojo {
    public void foo() {
        this.bar();
    }
    public void bar() {
        ...
    }
}

When we call the method foo(), it reinvokes the method bar() inside it. Even thought the method foo() is invoked from the AOP Proxy, the internal invocation of the bar() is not covered by the AOP Proxy.

Proxy calls

So eventually this makes, if there are any advices attached to the method bar() to not get invoked

Solution

Use AopContext.currentProxy() to call the method. Unfortunately this couples the logic with AOP.

public void foo() {
   ((Pojo) AopContext.currentProxy()).bar();
}

Reference:

http://docs.spring.io/spring/docs/current/spring-framework-reference/html/aop.html#aop-understanding-aop-proxies

###

You are running into a limitation of Spring AOP on self-invocation. You basically can get around it by using AopContext.currentProxy(), refactor code into different beans, or use full ApsectJ weaving.

See explanation here and workaround(s).
http://docs.spring.io/spring/docs/current/spring-framework-reference/html/aop.html#aop-understanding-aop-proxies

###

I guess the problem is the @args condition.

Spring documentation states the following:

@args - limits matching to join points (the execution of methods when using Spring AOP) where the runtime type of the actual arguments passed have annotations of the given type(s) 

Therefore the parameter of @args has to be a type expression. So the correct pointcut expression is

@AfterReturning(value = "execution(* com.enbiso.proj.estudo.system.service.impl.MessageServiceImpl.send(..)) && args(com.enbiso.proj.estudo.system.service.impl.Message")

or simply

@AfterReturning(value = "execution(* com.enbiso.proj.estudo.system.service.impl.MessageServiceImpl.send(com.enbiso.proj.estudo.system.service.impl.Message))")

Please adjust the package of Message if it doesn’t fit.