CallBack Using Inner Class in Java ?

Create interface seperately Incrementable .java


interface Incrementable {
  void increment();
}


Also create Callbacks.java
// Very simple to just implement the interface:

class Callee1 implements Incrementable {
  private int i = 0;

  public void increment() {
    i++;
    System.out.println(i);
  }
}

class MyIncrement {
  void increment() {
    System.out.println("Other operation");
  }

  static void f(MyIncrement mi) {
    mi.increment();
  }
}

// If your class must implement increment() in
// some other way, you must use an inner class:

class Callee2 extends MyIncrement {
  private int i = 0;

  private void incr() {
    i++;
    System.out.println(i);
  }

  private class Closure implements Incrementable {
    public void increment() {
      incr();
    }
  }

  Incrementable getCallbackReference() {
    return new Closure();
  }
}

class Caller {
  private Incrementable callbackReference;

  Caller(Incrementable cbh) {
    callbackReference = cbh;
  }

  void go() {
    callbackReference.increment();
  }
}

public class Callbacks {

  public static void main(String[] args) {
    Callee1 c1 = new Callee1();
    Callee2 c2 = new Callee2();
    MyIncrement.f(c2);
    Caller caller1 = new Caller(c1);
    Caller caller2 = new Caller(c2.getCallbackReference());
    caller1.go();
    caller1.go();
    caller2.go();
    caller2.go();
  }
}

Output :


Other operation
1
2
1
2