Spring AOP target() vs this()

spring spring-aop
rapt picture rapt · Aug 12, 2012 · Viewed 13.4k times · Source

From Spring Documentation:

  • any join point (method execution only in Spring AOP) where the proxy implements the AccountService interface:

    this(com.xyz.service.AccountService)

  • any join point (method execution only in Spring AOP) where the target object implements the AccountService interface:

    target(com.xyz.service.AccountService)

I don't understand what "target object" and the expression target(...) mean.

How is target different from this?

Answer

Biju Kunjummen picture Biju Kunjummen · Aug 12, 2012

this(AType) means all join points where this instanceof AType is true. So this means that in your case once the call reaches any method of AccountService this instanceof AccountService will be true.

target(AType) means all join points where anObject instanceof AType . If you are calling a method on an object and that object is an instanceof AccountService, that will be a valid joinpoint.

To summarize a different way - this(AType) is from a receivers perspective, and target(AType) is from a callers perspective.

Related questions

Spring - @Transactional - What happens in background?

I want to know what actually happens when you annotate a method with @Transactional? Of course, I know that Spring will wrap that method in a Transaction. But, I have the following doubts: I heard that Spring creates a proxy …

Read More
Spring AOP: What's the difference between JoinPoint and PointCut?

I'm learning Aspect Oriented Programming concepts and Spring AOP. I'm failing to understand the difference between a Pointcut and a Joinpoint - both of them seem to be the same for me. A Pointcut is where you apply your advice …

Read More
Spring AOP vs AspectJ

I am under the impression that Spring AOP is best used for application specific tasks such as security, logging, transactions, etc. as it uses custom Java5 annotations as a framework. However, AspectJ seems to be more friendly design-patterns wise. Can …

Read More