Question

I have methods set to public because they must be called by an exterior class, but I only ever want them called by one or two methods. Being called by other methods could create bugs in my program. So, in order to prevent me from accidentally programming around my own methods, I have been doing stuff like this within the methods of which I want to restrict callers:

if(trace.length<2){
    throw new Exception("Class should not call its own function.");
}else if(trace[1].getClassName()!=desiredClassName || trace[1].getMethodName()!=desiredMethodName){
    throw new Exception(trace[1].getClassName()+"\" is invalid function caller. Should only be called by "+desiredClassName+"->"+desiredMethodName+".");
}

Is there something else I should be doing, or should I just not forget how my program works?

Answer 1

You should be using visibility to restrict calling – making a method public (or for that matter, javadocing it) is not going to work unless you have dicipline (and you control the callers too). From your description, you are neither.

What you can do is make the class package private, and put it in the same package as the two callers of that class. As long as you have a proper package structure, this can work. E.g.:
Your class that should only be called by A and B:

package thepackage.of.a.and.b;
//imports here
class CallableByAB {
 public void methodA(){}
 public void methodB(){}
}

A:

package thepackage.of.a.and.b;
public class A { 
   /*...other code here */
   new CallableByAB().methodA();
   /*...other code here */
}

B:

package thepackage.of.a.and.b;
public class B { 
   /*...other code here */
   new CallableByAB().methodB();
   /*...other code here */
}

other classes cannot call new CallableByAB() or import it. hence, safety.