Spring Tutorials

There are five types of Advices as given below:

1. before advice: It is applied before calling the actual business logic.<aop:before></aop:before>
2. after-returning advice: It is applied after calling the actual business logic . It can be used to intercept the return value in advice. <aop:after-returning></aop:after-returning>
3. after-throwing advice: It is applied if actual business logic method throws exception.<aop:after-throwing></aop:after-throwing>
4. after advice: It is applied after calling the actual business logic.<aop:after></aop:after>
5. around advice: It is applied before and after calling the actual business logic.<aop:around></aop:around>

You can declare any of the five advices inside an <aop:aspect>...</aop:aspect> using the <aop: name="name">...</aop:>element as given below: Before advice runs before a matched method execution. It is declared inside an <aop:aspect> using the <aop:before> element.

<aop:aspect id="beforeExample" ref="loginAspect">
<aop:before pointcut-ref="businessService"
method="logRequiredTask">
...
</aop:before>
</aop:aspect>

After returning advice runs when a matched method execution completes normally. It is declared inside an <aop:aspect> in the same way as before advice.

<aop:aspect id="afterReturningExample" ref="loginAspect">
<aop:after-returning
pointcut-ref="businessService"
returning="retVal"
method="logRequiredTask"/>
...
</aop:aspect>

The logRequiredTask method must declare a parameter named retVal. For example, the method signature may be declared as:

 public void logRequiredTask(Object retVal) {...

After throwing advice executes when a matched method execution exits by throwing an exception. It is declared inside an <aop:aspect> using the after-throwing element:

<aop:aspect id="afterThrowingExample" ref="loginAspect">
<aop:after-throwing
pointcut-ref="businessService"
throwing="ex"
method="logRequiredTask"/>
...
</aop:aspect>

The logRequiredTask method must declare a parameter named ex. For example, the method signature may be declared as:

public void logRequiredTask(DataAccessException ex) {...

After (finally) advice runs however a matched method execution exits. It is declared using the after element:

<aop:aspect id="afterExample" ref="loginAspect">
<aop:after
pointcut-ref="businessService"
method="logRequiredTask"/>
...
</aop:aspect>

The final kind of advice is around advice. Around advice runs "around" a matched method execution. It has the opportunity to do work both before and after the method executes, and to determine when, how, and even if, the method actually gets to execute at all. Around advice is often used if you need to share state before and after a method execution in a thread-safe manner.

<aop:aspect id="aroundExample" ref="loginAspect">
<aop:around
pointcut-ref="businessService"
method="logRequiredTask"/>
...
</aop:aspect>