Monday 29 April 2013

Spring AOP - After Advice





After Advice (After Returning Advice)

  • Both (After Advice and After Returning Advice) are almost same and similar to before advice; only difference is that these services are applied after completion of our business logic.

  • We should implement AfterReturningAdvice interface and override afterReturning(Object returnVal, Method method, Object[] arg, Object target) method in order to create AfterReturningAdvice implementation class.

  • First parameter contains the return value of the business method or null, rest of the parameters is similar to before Advice method parameters.
Syntax Of  AfterReturningAdvice afterReturning() Method
public void afterReturning(Object returnVal, Method method, Object[] arg,
            Object target) throws Throwable {
        }

Steps for creating implementation for AfterreturningAdvice :-

1) Create a java file in com.gaurav.aop.advices package and name it as TraceLogAfterReturnMethodExecution.



2) Place the below code in that java file.

3) Create a java bean InternetClientService in the com.gaurav.aop.services package and place the below code in the bean file.


4) Create a xml bean file names spring-internet-client-service-beans-afteradvice.xml inside src folder and place the below code in that file.

5) Create a java file TraceLogMethodAfterAdviceClient.java in the package com.gaurav.aop.advices.client inside src folder.Place the below available code in that file.
 

TraceLogAfterReturnMethodExecution.java

package com.gaurav.aop.advices;

import java.lang.reflect.Method;

import org.springframework.aop.AfterReturningAdvice;

public class TraceLogAfterReturnMethodExecution implements AfterReturningAdvice {

    @Override
    public void afterReturning(Object returnVal, Method method, Object[] arg,
            Object target) throws Throwable {
        System.out
                .println("\n TraceLogAfterReturningAdvice:-Entered inside AfterReturningAdvice");

    }

}


InternetClientService.java

package com.gaurav.aop.services;

import org.springframework.transaction.IllegalTransactionStateException;

public class InternetClientService {
    private int internetUserId;
    private String internetUserName;
    private String connectionURL;

    public void setInternetUserId(int internetUserId) {
        this.internetUserId = internetUserId;
    }

    public void setInternetUserName(String internetUserName) {
        this.internetUserName = internetUserName;
    }

    public void setConnectionURL(String connectionURL) {
        this.connectionURL = connectionURL;
    }

    public void displayInternetUserId() {
        System.out.println("Internet User ID : " + this.internetUserId);
    }

    public void displayInternetUserName() {
        System.out.println("Internet User Name : " + this.internetUserName);
    }

    public void displayConnectionURL() {
        System.out.println("Connection URL in Internet is : "
                + this.connectionURL);
    }

    public void displayThrowException() {
        throw new IllegalTransactionStateException(internetUserName);
    }

}

spring-internet-client-service-beans-afteradvice.xml

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <bean id="internetClientService" class="com.gaurav.aop.services.InternetClientService">
        <property name="internetUserId" value="315260" />
        <property name="internetUserName" value="Gaurav Kumar" />
        <property name="connectionURL" value="http://www.javatechtipssharedbygaurav.com/" />
    </bean>

    <bean id="traceLogAfterMethodBean" class="com.gaurav.aop.advices.TraceLogAfterReturnMethodExecution" />

    <bean id="internetClientServiceProxy"
                class="org.springframework.aop.framework.ProxyFactoryBean">

        <property name="target" ref="internetClientService" />

        <property name="interceptorNames">
            <list>
                <value>traceLogAfterMethodBean</value>
            </list>
        </property>
    </bean>
</beans>

TraceLogMethodAfterAdviceClient.java

package com.gaurav.aop.advices.client;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.gaurav.aop.services.InternetClientService;

public class TraceLogMethodAfterAdviceClient{
    public static void main(String[] args) {
        ApplicationContext appContext = new ClassPathXmlApplicationContext(
                new String[] { "spring-internet-client-service-beans-afteradvice.xml" });

        InternetClientService internetClientService = (InternetClientService) appContext
                .getBean("internetClientServiceProxy");

        System.out
                .println(" \n ##### InternetUser ID in client application is as below ");

        internetClientService.displayInternetUserId();

        System.out
                .println(" \n ##### InternetUser Name in client application is as below ");

        internetClientService.displayInternetUserName();

        System.out
                .println(" \n ##### Connection URL for Internet in client application is as below ");

        internetClientService.displayConnectionURL();

        try {
            internetClientService.displayThrowException();
        } catch (Exception e) {

        }

    }
}

Result:- 





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