Tracking every time a method is called in some object?

Question

Hi,
I would like to use reflection to log every time some method is called in an object.
Example;
public class A {
public void x () { }
public void y () { }
I would like some automatic mechanism that would allow me to register this object such that every time method x() is called, I have a System.out.println (or some other logging) saying "method 'x' called" and the same for every time method y() is called ... without having to modify the body of each method I want to track. If I have to put my logging calls into every method, then it defeats the purpose of what I'm trying to accomplish.
Thank you,
Gene

Answer 1

If your method calls are through an interface, set up a proxy that logs the calls using java.lang.reflect.Proxy.
If they're through a class, you can't use reflection and need to either use code generation or bytecode manipulation (either roll your own or use an aspect oriented programming kit - logging is the canonical AOP example).
Pete