I am trying to implement one of the suggestion given by our stackoverflow member here Logging entry, exit and exceptions for methods in java using aspects . Since this is different question in itself, posting here again.
I have tried to search but looks like different versions have different ways of doing it and unable to figure out an example online. I have tried the following simple example since I am new to aspect oriented programming and couldn't figure out how to implement. This example is throwing NPE. Please help me understand where I am doing it wrong.
==== Exception
Exception in thread "main" java.lang.NullPointerException
at aoplogging.SimpleCall.call(SimpleCall.java:13)
at aoplogging.App.main(App.java:18)
Exactly at SimpleService.simpleCall();
ApplicationContext:
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:task="http://www.springframework.org/schema/task"
xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.2.xsd">
<aop:aspectj-autoproxy />
<bean id="simpleCall" class="aoplogging.SimpleCall" />
================== App.java
package aoplogging;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class App {
public static void main(String[] args) {
ConfigurableApplicationContext context = new ClassPathXmlApplicationContext("ApplicationContext.xml");
SimpleCall call =(SimpleCall) context.getBean("simpleCall");
call.call();
context.close();
}
============ SimpleCall.java package aoplogging;
import org.springframework.beans.factory.annotation.Autowired;
public class SimpleCall {
@Autowired
private SimpleService SimpleService;
public void call(){
SimpleService.simpleCall();
try {
SimpleService.processingOperator();
} catch (SMSProcessingException | SMSSystemException e) {
e.printStackTrace();
}
}
}
=====Logging.java
package aoplogging;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
@Aspect
public class Logging {
@Pointcut("execution(* aoplogging.*.*(..))")
private void selectAll(){}
/**
* This is the method which I would like to execute
* before a selected method execution.
*/
@Before("selectAll()")
public void beforeAdvice(){
System.out.println("Going to setup student profile.");
}
/**
* This is the method which I would like to execute
* after a selected method execution.
*/
@After("selectAll()")
public void afterAdvice(){
System.out.println("Student profile has been setup.");
}
/**
* This is the method which I would like to execute
* when any method returns.
*/
@AfterReturning(pointcut = "selectAll()", returning="retVal")
public void afterReturningAdvice(Object retVal){
System.out.println("Returning:" + retVal.toString() );
}
/**
* This is the method which I would like to execute
* if there is an exception raised by any method.
*/
@AfterThrowing(pointcut = "selectAll()", throwing = "ex")
public void AfterThrowingAdvice(IllegalArgumentException ex){
System.out.println("There has been an exception: " + ex.toString());
}
}
