Inner class within Interface

by

Yes, we can have classes inside interfaces. One example of usage could be 

public interface Input
{
    public static class KeyEvent {
         public static final int KEY_DOWN = 0;
         public static final int KEY_UP = 1;
         public int type;
         public int keyCode;
         public char keyChar;
    }
    public static class TouchEvent {
         public static final int TOUCH_DOWN = 0;
         public static final int TOUCH_UP = 1;
         public static final int TOUCH_DRAGGED = 2;
         public int type;
         public int x, y;
         public int pointer;
    }
    public boolean isKeyPressed(int keyCode);
    public boolean isTouchDown(int pointer);
    public int getTouchX(int pointer);
    public int getTouchY(int pointer);
    public float getAccelX();
    public float getAccelY();
    public float getAccelZ();
    public List<KeyEvent> getKeyEvents();
    public List<TouchEvent> getTouchEvents();
}

Here the code has two nested classes which are for encapsulating information about event objects which are later used in method definitions like getKeyEvents(). Having them inside the Input interface improves cohesion.

More Related Contents:

  1. Abstract class in Java
  2. Why is there no multiple inheritance in Java, but implementing multiple interfaces is allowed?
  3. Is there more to an interface than having the correct methods
  4. What is an interface in Java?
  5. Why to use Interfaces, Multiple Inheritance vs Interfaces, Benefits of Interfaces?
  6. How should I have explained the difference between an Interface and an Abstract class?
  7. Should we @Override an interface’s method implementation?
  8. Can we create an instance of an interface in Java? [duplicate]
  9. Can we create an object of an interface?
  10. “Non-static variable this cannot be referenced from a static context” when creating an object
  11. How one interface can be used for different background android tasks?
  12. Do/can abstract classes replace interfaces? [duplicate]
  13. When do I have to use interfaces instead of abstract classes? [duplicate]
  14. Should you always Code To Interfaces In Java [closed]
  15. interface as a method parameter in Java
  16. What are the purposes of inner classes
  17. Why are interfaces preferred to abstract classes?
  18. How much interfaces a class file can implement [closed]
  19. The purpose of interfaces continued
  20. What causes error “No enclosing instance of type Foo is accessible” and how do I fix it?
  21. What is the difference between dynamic and static polymorphism in Java?
  22. Instantiating inner class
  23. What does it mean to program to an interface?
  24. Missing return statement in a non-void method compiles
  25. mocking a singleton class
  26. Is it bad practice to make a setter return “this”?
  27. How to do method overloading for null argument?
  28. Casting a class to an unrelated interface
  29. What is the difference between a fluent interface and the Builder pattern?
  30. what is the actual use of interface in java? [duplicate]

Leave a Comment