The listener interface for receiving mouse wheel events on a component.
 (For clicks and other mouse events, use the MouseListener.
 For mouse movement and drags, use the MouseMotionListener.)
 
The class that is interested in processing a mouse wheel event implements this interface (and all the methods it contains).
 The listener object created from that class is then registered with a
 component using the component's addMouseWheelListener
 method. A mouse wheel event is generated when the mouse wheel is rotated.
 When a mouse wheel event occurs, that object's mouseWheelMoved
 method is invoked.
 
 For information on how mouse wheel events are dispatched, see
 the class description for MouseWheelEvent.
extends 
MouseWheelEvent