Getting invoker object

Question

How could I get the reference of a calling object?
An example:
class A {
method() {
B b = new B();
class B {
public B() {
/*getInstanceOfClassA*/
In class B I need the instance of the class A (a), without passing "this" to B (or b).
I suppose that it could be possible by using the stack trace or reflections, couldn't it?
Thanx
Marc

Answer 1

i'm interested to know what problem you're trying to solve that you would need this capability. i mean, if you want a method to have visibility to the object that called it, why not just pass it as a parameter to the method?
generally speaking, the "don't talk to strangers" design principle (also known as the "law of demeter") tells us that a method should send messages only to direct objects to avoid unnecessary coupling--a) self; b) a parameter of the method; c) an attribute of self; d) an element of a collection which is an attribute of self; or e) an object created within the method.
flipping this around a bit, if you want the calling object to be visible to the called object, you can create the visibility by passing the calling object as a parameter to the method, or making it globally visible somehow. i don't see how you'd get around that, or why you'd want to. i need to understand the problem you're trying to solve using the technique you desire.
you can discover the name of the method that called your method by creating a new Throwable and parsing its stack trace. Log4J uses this trick to discover the name of the class and method requesting that a log be written. this is discussed in numerous other posts.