How can a custom class call a function in "parent" class?

Question

Say I have an application (ultrasimplified):
public class myApp {
myClass mc;
boolean foo=false;
public static void main(String[] args) {
mc = new myClass();
public static void myFunc(boolean blah) {
foo=blah;
in a separate .java file where my questions lie:
public class myClass {
boolean bar=true;
public void myClass() {
// this is wrong, but how would I do this:
foo = bar; // foo in myApp set to true
// or how would I call "myFunc()" in myApp from this class:
myFunc(bar);
my problem is that I've created a new class that I share between two applications so I could share the code. However, I want this class I created to call a function in the application class that instanciated it. Or alternatively, I would like to set a variable in the class that instanciated myClass.
How would go about this? I've used the "this" parameter in applets to pass the parent class to an inner class, but main() in applications doesn't allow the non-static "this":
myClass my = new myClass(this);
Is there something similar I can do?

Answer 1

You can let MyApp implement an interface and refer to that object in MyClass:
class MyApp implements Something {
main() {
MyApp app = new MyApp();
MyClass mc = new MyClass(app);
public void foo() { }
class MyClass {
Something app;
MyClass(Something app) {
this.app = app;
app.foo();
interface Something {
public void foo();
Better yet, you can let MyApp extend an abstract class that defines foo(). Then MyApp can override the foo() method. If later on, the abstract class needs to add a bar() method then default implementation can be done in the abstract class. If you make it an interface then all implementing classes will have to be updated to implement the new method.