Get caller instance (via reflection)

Question

Is it somehow possible to get an instance object of a calling class?

class A{ void foo(){ Object o = getCaller(); //?? expect instance of B long val1 = .. // get val1 of o via reflection // do something where val1 is crucial } } class B{ double val1 = Math.random(); public static void main(String[] args) { new B().callFoo(); } void callFoo(){ new A().foo(); } } 

I know that I can recognize a class / method call using stacktrace, but I need a conrete instance to access the instance variables (e.g. val1 in the example).

I know that it is dirty, but class B is in an immutable library, so it is almost impossible to pass the required field without rebuilding everything.

Answer 1

You cannot access the instance of the caller unless the instance is somehow transferred to it or stored in the collection.

To transfer an instance, you can do the following:

 class A{ void foo(Object caller){ long val1 = .. // do something where val1 is crucial } } class B{ double val1 = Math.random(); public static void main(String[] args) { new B().callFoo(); } void callFoo(){ new A().foo(this); } } 

The key "this" will pass the instance of the calling code to the foo method in class A