781: Mainline

One way to write the listener class in which you define the mouseClicked method is to define the listener class as a local class in the MovieApplication class, as shown in the following example, which also features a modification to a setter that calls the addMouseListener method, which the Meter class inherits from the Component class.

The setMeter setter is not as complex as the setMovie setter because setMeter is called just once, whereas setMovie is called many times, once a choice list is added in Chapter 46,

import javax.swing.*;
import java.awt.event.*;
import java.util.*;
public class MovieApplication extends JFrame {
 public static void main (String argv []) {
  new MovieApplication("Movie Application");
 }
 // Declare instance variables:
 private Meter meter;
 private Movie movie;
 // Define constructor
 public MovieApplication(String title) {
  super(title);
  // Create model
  getMovie();
  // Create and connect view to application
  getContentPane().add("Center", getMeter());
  // Connect window listener, size and show
  addWindowListener(new LocalWindowListener());
  setSize(300, 100);
  show();
 }
 // Define getters and setters
 public Meter getMeter () {
  if (meter == null) {setMeter(new Meter(0, 30));}
  return meter;
 }
 public Movie getMovie () {
  if(movie == null) {setMovie(new Movie (10, 10, 10, "On to Java"));}
  return movie;
 }
 public void setMovie (Movie m) {
  if(movie == m) {return;}
  if(movie instanceof Movie) {movie.deleteObservers();}
  if(m instanceof Movie) {
   movie = m;
   movie.addObserver(new LocalMovieObserver());
   movie.changed();
 }}
 public void setMeter (Meter m) {                                     
  meter = m;                                                          
  meter.addMouseListener(new LocalMeterListener());                   
 }                                                                    
 // Define observer:
 private class LocalMovieObserver implements Observer {
  public void update (Observable observable, Object object) {
   getMeter().setValue(getMovie().rating());
   getMeter().setTitle(getMovie().getTitle());
  }
 }
 // Define mouse adapter:
 private class LocalMeterListener extends MouseAdapter {              
  public void mouseClicked (MouseEvent e) {                           
   int x = e.getX();                                                  
   int y = e.getY();                                                  
   int v = (int) Math.round(getMeter().getValueAtCoordinates (x, y)   
                 / 3.0);                                              
   getMovie().setScript(v);                                           
   getMovie().setActing(v);                                           
   getMovie().setDirection(v);                                        
  }                                                                   
 }                                                                    
 // Define window adapter        
 private class LocalWindowListener extends WindowAdapter { 
  public void windowClosing(WindowEvent e) { 
   System.exit(0); return; 
  } 
 } 
}