Implementing Advice

As you know that, Spring provides five types of advices, let's see work flow of one by one.

Advice type - Before

Let's see the following figure for before advice. This advice executes the before the target method:

As you can see in figure, before advice is executed first and then it calls the Target method. As we know that Spring AOP is proxy-based. So a Proxy object is created of target class. It is based on Proxy design pattern and Decorator Design Pattern.

Before Advice example

Let's see the use of @Before annotation:

    //Before transfer service 
    @Before("execution(* com.packt.patterninspring.chapter6.
    bankapp.service.TransferService.transfer(..))")  
    public void validate(){ 
      System.out.println("bank validate your credentials before amount 
      transferring"); 
    } 
 
    //Before transfer service 
    @Before("execution(* com.packt.patterninspring.chapter6.
    bankapp.service.TransferService.transfer(..))")  
    public void transferInstantiate...