Spring AOP Terminology

There are some important terms in Spring AOP which we need to know about. All total there are 8 terms which are as follows :

1. Aspect

2. Advice

3. JoinPoint

4. PointCut

5. Advisor

6. Target

7. Proxy

8. Weaving

Aspect : It is one of the main concept in AOP which is programmatically represented as Middle Level Services(Sercurity, transaction, log etc) . Advices are applied to the Aspect.

For ex- Aspects are the middle level services like SecurityService, LogService, TransactionService etc are applied to the three JoinPoints of the Business Logic through Advices. 

Advice :  It is the required implementation of the Middle Level Services which tells about the method execution of different Aspects at the joinPoint. 

Advice is a Java class which contains the information about the execution of method of Middle level services at the different joinPoints. So basically it tells the container what to execute?  

JoinPoint : It is point or concept which tells where we want to apply Advice. It tells container when to execute?

Basically there are three joinPoints are provided by the Spring AOP i.e

1. Method Before 

2. Method Returning 

3. Method Throwing  

a) Method Before : It tell the container to execute the codes before the core logic to be execute. It is provided by the Spring in the form of a method called Before() present in the MethodBeforeAdvice interface.

b) Method Returning : It tells the container to execute the codes after successfully returning the control from the core logic. It is iimplemented using methodAfterReturning() method present in the methodAfterReturningAdvice interface.

c) Method Throwing : It tells the container to execute the codes when container throws execution while executing the core logic. It is implemented using methodAfterThrowing() method provided in the ThrowsAdvice interface. 

PointCut : It is the collection of JoinPoints. Previously JoinPoints are common for all core logic but now with the pointCut we have the option to tell Container to apply which JoinPoints to which core logics. 

Advisor : For telling the Container to apply these JoinPoints to the selected core logic we need joinPoint and Advice to configure in a Advisor. So Advisor is a collection of both JoinPoints and PointCuts. 

Target : It is the main object of our Business Service before applying the Advices or Advisors.It will directly call and execute the codes of core logic. 

Proxy : It is an object of our business service after applying Advices or Advisors. Calling the core logic with the Proxy calls the dynamic code generated by the Container which contains advices with the core logic. 

Weaving : It is the process of applying the Advice/Advisor to the target objects at given PointCuts to get the proxy objects.