Spring AOP - How to get annotation of parent(caller) method - aop

Question

#Before(value="#annotation(com.aspect.Loggable)",argNames="taskId")
public void logEmail(JoinPoint joinPoint) {
System.out.println("#Before is running!");
System.out.println("hijacked : " + joinPoint.getSignature().getName());
System.out.println("******");
}
i have a pointCut on method sendEmail() with custom annotation.
This method sendEmail() is called from differnt location in our application .
Like we call sendEmail from paymentApproved () method of paymentManager when payment is approved.
We call sendEmail from taskComplete() method of taskManger when task is completed.
i have to find out the event for which sendEmail is triggered.
I applied custom annotation #EVENT("PAYMENT") on paymentApproved () of paymentManager and #EVENT("TASK") on taskComplete() method of taskManger.
How can i get the value of #EVENT in logEmail(JoinPoint joinPoint) aspect.

Answer 1

Scaffolding:
Sorry, I do not like all-caps class names and I also used my own package names as an example because my template already generates them.
package de.scrum_master.app;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
#Retention(RetentionPolicy.RUNTIME)
public #interface Loggable {}
package de.scrum_master.app;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
#Retention(RetentionPolicy.RUNTIME)
public #interface Event {
String value();
}
Driver application:
This is pure Java because I am not a Spring user. Just imagine it is one or more #Components.
Please also note that in one case sendEmail() is called from a method not annotated by #Event. This should not trigger the aspect, only the two calls from the annotated methods.
package de.scrum_master.app;
public class Application {
public static void main(String[] args) {
Application application = new Application();
application.doSomething();
application.paymentApproved();
application.taskComplete();
}
public void doSomething() {
sendEmail();
}
#Event("paymentApproved")
public void paymentApproved() {
sendEmail();
}
#Event("taskComplete")
public void taskComplete() {
sendEmail();
}
#Loggable
public void sendEmail() {}
}
Aspect:
Your pointcut wants to express: Catch methods annotated with #Loggable within the control flow of methods annotated by #Event. Control flow can be expressed by cflow() or cflowbelow() pointcuts.
package de.scrum_master.aspect;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import de.scrum_master.app.Event;
#Aspect
public class LogAspect {
#Before(
"#annotation(de.scrum_master.app.Loggable) &&" +
"execution(* *(..)) &&" + // only needed for AspectJ, not for Spring AOP
"cflow(#annotation(event))"
)
public void logEmail(JoinPoint thisJoinPoint, Event event) {
System.out.println(thisJoinPoint + " -> " + event);
}
}
Console log:
execution(void de.scrum_master.app.Application.sendEmail()) -> #de.scrum_master.app.Event(value=paymentApproved)
execution(void de.scrum_master.app.Application.sendEmail()) -> #de.scrum_master.app.Event(value=taskComplete)
Update: If you were using full AspectJ (e.g. via load-time weaving) instead of Spring AOP, you just could have used a call() pointcut and from there get the enclosing joinpoint's static information. Then the #Event annotation would not have been necessary. But Spring AOP is just "AOP lite" and does not support call().

Answer 2

You can access to the annotation receiving it as a parameter. Something like this:
#Before(value="#annotation(EVENT)",argNames="taskId")
public void logEmail(JoinPoint joinPoint, Event event) {
// do what you need with event. For example, if the field is called value you can do this:
if ("PAYMENT".equals(event.value())) {
// do sth
}
System.out.println("#Before is running!");
System.out.println("hijacked : " + joinPoint.getSignature().getName());
System.out.println("******");
}