I need help to write some Aspectj advice on this particular case:
Suppose we have this class:
package org.group;
public class Person {
public void method1(String id, String number) {
//some code
List<String> list = getList(number);
//some code
}
public List<String> getList(String number) {
return Arrays.asList(number);
}
}
I want to create an Aspectj advice into method1 to get the result of getList. I try this:
@Pointcut("execution(* org.group.Person.getList(..))")
public void methodGetList() {
}
@AfterReturning(pointcut = "methodGetList()", returning = "result")
public void afterMethodGetList(JoinPoint joinPoint, List<String> result) {
System.out.println("I can see the list result: " + result.toString());
}
This advice works on all executions of getList method, but what I want exactly, is to get the result inside the method1 call to get an information with the method1's id , for example like this:
'I can see the list result [4] for the person with id : XXX'
Thank you for your help.
You need to limit your pointcut to the executions within the control flow - cflow()
- of the calling method and also bind the calling method's parameter of interest via args()
.
Application:
package org.group;
import java.util.Arrays;
import java.util.List;
public class Person {
public void method1(String id, String number) {
// some code
List<String> list = getList(number);
// some code
}
public List<String> getList(String number) {
return Arrays.asList(number);
}
public static void main(String[] args) {
// Should not be intercepted
new Person().getList("22");
// Should be intercepted
new Person().method1("John Doe", "11");
}
}
Aspect:
package de.scrum_master.aspect;
import java.util.List;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
@Aspect
public class MyAspect {
@Pointcut("execution(* org.group.Person.getList(..))")
public void methodGetList() {}
@Pointcut("execution(* org.group.Person.method1(..)) && args(id, *)")
public void methodMethod1(String id) {}
@AfterReturning(
pointcut = "methodGetList() && cflow(methodMethod1(id))",
returning = "result"
)
public void afterMethodGetList(JoinPoint joinPoint, String id, List<String> result) {
System.out.println(
"I can see the list result " + result +
" for the person with id " + id
);
}
}
Console log:
I can see the list result [11] for the person with id John Doe