Add toString method to class using AspectJ

Question

I have a class which I can't modify but I want to change the behaviour of one of it's methods.

public class TestClass {
}

I would like to pointcut the toString method inside of it so instead of returning "TestClass@a8d8as" it will return "hello".

@Around("execution(* *(..)) && this(com.test.TestClass)")

This works If I define the toString method inside TestClass, but won't work with the implicit one.

I haven't worked with aspects for a long time and I'm quite new at them, is there something I'm missing or a way to do what I want?

Thanks!

Answer 1

You asked for an AspectJ solution despite having solved the problem via Javassist. So here it is according to Nándor's suggestion:

package de.scrum_master.app;

public class TestClass {
  private String tableName;

  public TestClass(String tableName) {
    this.tableName = tableName;
  }

  public static void main(String[] args) {
    System.out.println(new TestClass("Invoice"));
    System.out.println(new TestClass("InvoiceItem"));
  }
}

package de.scrum_master.aspect;

import de.scrum_master.app.TestClass;

public privileged aspect ToStringAspect {
  public String TestClass.toString() {
    return tableName;
  }
}

Console log:

Invoice
InvoiceItem