Implementing a listener interface

Switch discussion to source-listener event handling.  With this event model

• Listener object is instantiated from class that implements specific listener interface. 
  • (Will use MouseListener interface.)
• Listener object is registered on  object that fires events of type associated with listener interface. 
  • (Will be events of type MouseEvent.)
• When source object fires event of  specified type,
  • one of methods belonging to registered listener object is called. 

Different methods belonging to the listener object are declared in the implemented listener interface.