Java Tutorial/Spring/AfterReturningAdvice

After Returning Advice

File: Main.java

   <source lang="java">

import java.lang.reflect.Method; import org.springframework.aop.AfterReturningAdvice; import org.springframework.aop.framework.ProxyFactory; public class Main {

 public static void main(String[] args) throws Exception {
   MessageWriter target = new MessageWriter();
   // create the proxy
   ProxyFactory pf = new ProxyFactory();
   pf.addAdvice(new SimpleAfterReturningAdvice());
   pf.setTarget(target);
   MessageWriter proxy = (MessageWriter) pf.getProxy();
   // write the messages
   proxy.writeMessage();
 }

} class MessageWriter {

 public void writeMessage() {
     System.out.println("A");
 }

} class SimpleAfterReturningAdvice implements AfterReturningAdvice {

 public void afterReturning(Object returnValue, Method method, Object[] args,
         Object target) throws Throwable {
     System.out.println("After method: " + method.getName());
 }

}</source>

Check Logic In After Returning Advice

File: Main.java

   <source lang="java">

import java.lang.reflect.Method; import org.springframework.aop.AfterReturningAdvice; import org.springframework.aop.framework.ProxyFactory; public class Main {

 public static void main(String[] args) {
   KeyGenerator target = new KeyGenerator();
   ProxyFactory factory = new ProxyFactory();
   factory.setTarget(target);
   factory.addAdvice(new WeakKeyCheckAdvice());
   KeyGenerator keyGen = (KeyGenerator) factory.getProxy();
   System.out.println("Key: " + keyGen.getKey());
 }

} class KeyGenerator {

 public static final long WEAK_KEY = 1L;
 public static final long STRONG_KEY = 2L;
 public long getKey() {
   return WEAK_KEY;
   // return STRONG_KEY;
 }

} class WeakKeyCheckAdvice implements AfterReturningAdvice {

 public void afterReturning(Object returnValue, Method method, Object[] args, Object target)
     throws Throwable {
   if ((target instanceof KeyGenerator) && ("getKey".equals(method.getName()))) {
     long key = (Long) returnValue;
     if (key == KeyGenerator.WEAK_KEY) {
       System.out.println("a weak key");
     }
   }
 }

}</source>