Hello Friends, After discussing the pointcuts in last post Now discuss on Joinpoint . A Joinpoint is a point in the execution of the application where an aspect can be plugged in. this point could be a method being called Here is a example to understands the use of pointcuts-
Output
Circle.java-
package com.test.App;
public class Circle {
String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
Triangle.java
package com.test.App;
public class Triangle {
String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
LogAspect.java
package com.test.aspect;
import org.aspectj.lang.JoinPoint;
//import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
@Aspect
public class LogAspect {
@Before("allGetters()")
public void loggingAd(JoinPoint jp)
{
System.out.println(jp.toString());
}
@Before("allcircle()")
public void loggingAdvice(JoinPoint jp)
{
System.out.println(jp.toString());
}
@Pointcut("execution(* get*())")
public void allGetters()
{
System.out.println("Wel Come With....allgetters");
}
@Pointcut("within(com.test.App.Circle)")
public void allcircle()
{
System.out.println("Wel Come With....circle");
}
}
Shape.java
package com.test.service;
import com.test.App.Circle;
import com.test.App.Triangle;
public class Shape {
Circle circle;
Triangle triangle;
public Circle getCircle() {
return circle;
}
public void setCircle(Circle circle) {
this.circle = circle;
}
public Triangle getTriangle() {
return triangle;
}
public void setTriangle(Triangle triangle) {
this.triangle = triangle;
}
}
Main.java-
package com.test.aop;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.test.service.Shape;
public class Main {
public static void main(String[] args) {
ApplicationContext context=new ClassPathXmlApplicationContext("spring.xml");
Shape sh=context.getBean("shape", Shape.class);
System.out.println(sh.getTriangle().getName());
System.out.println(sh.getCircle().getName());
}
}
Spring.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"
xmlns:context="http://www.springframework.org/schema/context">
<aop:aspectj-autoproxy/>
<bean id="triangle" class="com.test.App.Triangle">
<property name="name" value="triangle drawn"></property>
</bean>
<bean id="circle" class="com.test.App.Circle">
<property name="name" value="circle drawn"></property>
</bean>
<bean id="shape" class="com.test.service.Shape" autowire="byName">
</bean>
<bean id="log" class="com.test.aspect.LogAspect"></bean>
</beans>
Output
execution(Triangle com.test.service.Shape.getTriangle())
execution(String com.test.App.Triangle.getName())
triangle drawn
execution(Circle com.test.service.Shape.getCircle())
execution(String com.test.App.Circle.getName())
execution(String com.test.App.Circle.getName())
circle drawn
JoinPoint class contain the information related to the object which pass by pointcut.
execution(String com.test.App.Triangle.getName())
triangle drawn
execution(Circle com.test.service.Shape.getCircle())
execution(String com.test.App.Circle.getName())
execution(String com.test.App.Circle.getName())
circle drawn
For Further Reading,
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