[FIXED] Confirmation message using Spring AOP - AspectJ

Issue

I am trying to learn Spring AOP implementation using AspectJ. I have 5 classes in different packages.

package com.sample.a;
Class A{
    public void save(){
    }
    }
}

---

package com.sample.b;
Class B {
    public void save(){
    }
}

---

package com.sample.c;
Class C {
    public void save(){
    }
}

---

package com.sample.d;
Class D{
    public void save(){
    }
}

---

package com.sample.e;
Class E{
    public void save(){
    }
}

Whenever these method gets called, I need to print "Hello World", How can I achieve the above scenario using Spring AOP (AspectJ). I have done the following so far -

1) Enabled Spring AspectJ support in applicationContext.xml

<aop:aspectj-autoproxy />

2) Defined reference of Aspect in applicationContext.xml

<bean id="sampleAspectJ" class="com.sample.xxxxxxxx" />

3) Aspect Class

/**
 * aspect class that contains after advice 
 */
package com.sample;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;

@Aspect
public class SpringAopSample{

    @After(value = "execution(* com.sample.*.Save(..))")
    public void test(JoinPoint joinPoint) {


        System.out.println("Hello World");



    }

}

is there any better way to achieve the above scenario? what if these 5 classes are in different packages and have different method names? Do I need to write 5 different methods in aspect (annotated with @after advice)

Solution

You should get acquainted with AspectJ pointcut syntax. For instance

• your own pointcut execution(* com.sample.*.Save(..)) from the example will not match any of the sample save() methods because
  • you wrote Save() with a capital "S", but the methods have lower-case "s" as their first character,
  • your classes would rather match com.sample.*.* (sub-package!) than just com.sample.*.
• So you can match all save() methods in sub-package classes like this: execution(* com.sample.*.*.save(..)). The first * is the subpackage a to d, the second * is the class name.
• If you want to match sub-packages and even classes hierarchically to any depth you can just use the .. syntax like this: execution(* com.sample..save(..))
• If you want to match only public void methods of any name and without parameters in all sub-packages, you can use execution(public void com.sample..*())

And so forth. I hope this answers your question even though it is kind of unclear what exactly you want to know.

Answered By - kriegaex