Difference between this and target in Spring AOP?

[yazad3]

Hi,

As per the documentation in section 6.2.3.1

this - limits matching to join points (the execution of methods when using Spring AOP) where the bean reference (Spring AOP proxy) is an instance of the given type

target - limits matching to join points (the execution of methods when using Spring AOP) where the target object (application object being proxied) is an instance of the given type

While I understand the 2 statements in essence, what confuses me is the benefit of these 2 being separately spelled out in Spring, since in Spring AOP all target objects in Spring AOP would always be proxied, as per section 6.1.1 of the documentation,

Target object: object being advised by one or more aspects. Also referred to as the advised object. Since Spring AOP is implemented using runtime proxies, this object will always be a proxied object.

-Yazad Khambata

[yazad3]

I read the Introductions section and saw an example on use of this, and everything started to fall in place. Thanks my question is answered I guess!

@Aspect
public class UsageTracking {

  @DeclareParents(value="com.xzy.myapp.service.*+",
                  defaultImpl=DefaultUsageTracked.class)
  public static UsageTracked mixin;
  
  @Before("com.xyz.myapp.SystemArchitecture.businessService() &&" +
          "this(usageTracked)")
  public void recordUsage(UsageTracked usageTracked) {
    usageTracked.incrementUseCount();
  }
  
}

It's "this" that implements UsageTracked and NOT "target"!