Call a method from the parent class?

[Znupi]

Is there a way to call from an instantiated class a method of the instantiating class? Here's what I mean, let's say I have two files:

MainClass.java

public class MainClass {
public static void testFunc() {
System.out.println("testFunc() was called!");
}
public static void main(String[] args) {
SubClass mySubClass = new SubClass();
}
}

SubClass.java

public class SubClass {
public static void SubClass() {
PARENT_CLASS.testFunc();
}
}

Is there a way to do this? I am very new to Java so please bear with me and tell me if I'm dead wrong :o

[chazzy]

well, that depends

Does SubClass extend MainClass? if so then you can call it using the super keyword.

If it doesn't, then you need to create an instance of MainClass to invoke it.

[Znupi]

No, it doesn't extend it. But here's another method I think wold work (didn't test it yet):
MainClass.java

public class MainClass {
public static void testFunc() {
System.out.println("testFunc() was called!");
}
public static void main(String[] args) {
SubClass mySubClass = new SubClass(this);
}
}

SubClass.java

public class SubClass {
public static void SubClass(MainClass parentClass) {
parentClass.testFunc();
}
}

Eventually I can store parentClass in an instance variable. Is this a good way of doing it? Are there better ways?

Thanks :)

[chazzy]

just so you know, when you talk about a "parent class" and "subclass" it's typically expected that the parent class means that it's the base class for the subclass. :)

there's several forms of polymorphism - there's polymorphism by inclusion/containment and polymorphism by extension. both work. containment is better at encapsulating changes, but extending is standard.

As for your example, you can't use "this" keyword in a static method. static methods have no instance relationship.

[Znupi]

That makes sense. Actually, in my application I wasn't using it in a static method, I was using this in a class constructor, like:
BaseClass.java

import javax.swing.*;

public class BaseClass extends JApplet {
public BaseClass() {
SubClass subclass = new SubClass(this);
}
}

I guess this way it should work, right?
Thanks for your replies :)