problem with refactored program

[Randall Twede]

the other day i finished refactoring an old java1 applet. i spent about a half hour fixing the cimpiler errors and a couple runtime problems but there is still one problem remaining and i cant seem to figure out what i did wrong. the new version has 4 classes. the problem must be in Farm.java or TextScroller.java since the DisplayArea works just fine. it displays the various images and plays the associated audio clips when clicked. the problem is the text scroller no longer appears. i appologize for posting so much code but i have no idea where exactly the problem is. if you can see the problem or have suggestions on how i can track it down i will be grateful.

ps. sorry about the bad copy and paste. i guess i should start using notepad instead of wordpad.

/*
 * @author Randall Twede
 */

import java.awt.*; 
import java.awt.event.*; 
import java.applet.*;

public class Farm extends Applet implements ItemListener
{
    Animal[] animals;	//allow DisplayArea and TextScroller access
    Choice choice;	//allow DisplayArea and TextScroller access
    String message;	//allow TextScroller access
    private DisplayArea farm;
    private TextScroller scroller;
    private int selection;
    private Thread runner;

    public void init()
    {
        animals = new Animal[6];
        choice = new Choice();
        message = "Select an animal";
        farm = new DisplayArea(this);
        scroller = new TextScroller(this);
        selection = 6;
        initComponents();
        setBackground(Color.BLACK);
        setLayout(new BorderLayout());
        add(scroller, BorderLayout.SOUTH);
        add(farm, BorderLayout.CENTER);
        add(choice, BorderLayout.WEST);
        runner = new Thread(scroller);
    }

    private void initComponents()
    {
        animals[0] = new Animal("sheep", "sheep.jpg", "sheep.au", "Click the sheep");
        animals[1] = new Animal("dog", "dog.gif", "dog.au", "Click the dog");
        animals[2] = new Animal("bird", "bird.jpg", "bird.au", "Click the bird");
        animals[3] = new Animal("cow", "cow.jpg", "cow.au", "Click the cow");
        animals[4] = new Animal("rooster", "rooster.jpg", "rooster.au", "Click the rooster");
        animals[5] = new Animal("donkey", "donkey.jpg", "donkey.au", "Click the donkey");        
        choice.setFont (new Font("Dialog", 0, 11));
        choice.setBackground(Color.white);
        choice.setForeground(Color.black);
        for(int i = 0; i < 6; i++)
	  {
            Animal animal = (Animal)animals[i];
            choice.add(animal.getName());
        }
        choice.addItemListener(this);       
    }

    public void itemStateChanged(ItemEvent e)
    {
	  Animal animal;
        Image image;
	  
        selection = choice.getSelectedIndex();
	  animal = (Animal)animals[choice.getSelectedIndex()];
        image = this.getImage(this.getDocumentBase(), animal.getImage());
        farm.updateImage(image); 
    } 
}

/*class to display scrolling text
 *to scroll a single message pass a String to it
 *to scroll a variety of messages pass "this" to it
 *
 *comment out specified lines for single message version
 *edit specified lines for multiple message version
 */

/*
 * @author Randall Twede
 */

import java.awt.*; 

public class TextScroller extends Canvas implements Runnable
{
    private String message;
    private Farm parent;	//comment out or edit
    private Image OSC;
    private Graphics OSC_graphics;
    private int min_x, max_x;
    private int message_x, message_y = 16;
    private int scroll_frames = 100;
    private int sleepTime = 100;
    private int width = 400;
    private int height = 20;

    public TextScroller(String message)
    {
        this.message = message;
        setSize(width,height);
    }

    public TextScroller(String message, int width)
    {
        this.message = message;
	  this.width = width;
        setSize(width,height);
    }

    public TextScroller(Farm parent)	//comment out or edit
    {							//comment out or edit
        this.parent = parent;			//comment out or edit
        setSize(width,height);		//comment out or edit
    }							//comment out or edit

    public TextScroller(Farm parent, int width)	//comment out or edit
    {								//comment out or edit
        this.parent = parent;				//comment out or edit
	  this.width = width;				//comment out or edit
        setSize(width,height);			//comment out or edit
    }								//comment out or edit

    synchronized public void paint(Graphics g)
    {
        if (OSC != null)  // if off-screen image exists, copy it to screen
        {
            g.drawImage(OSC,0,0,this);
        }
        else  // otherwise, fill the canvas with the background color
        {
            g.setColor(getBackground());
            g.fillRect(0,0,width,height);
        }
    }    
       
    public void update(Graphics g)
    {
        // redefine update() so that it doesn't erase the applet;
        // this will avoid flickering when the applet is redrawn
        paint(g);
    }

    synchronized private void drawNextFrame(int scroll_frame)
    {
        OSC = createImage(width,height);
        OSC_graphics = OSC.getGraphics();
        Font font = getFont();
        font = new Font("TimesRoman",Font.PLAIN,15);
        OSC_graphics.setFont(font);
        FontMetrics fm = getFontMetrics(font);
        min_x = -fm.stringWidth(message);
        max_x = width;
        message_x = max_x - ((scroll_frame * (max_x-min_x)) / scroll_frames);
        OSC_graphics.setColor(Color.white);
        OSC_graphics.fillRect(0,0,width,height);
        OSC_graphics.setColor(Color.black);
        OSC_graphics.drawString(message,message_x,message_y);
    }

    public void run()
    {
	  Animal animal;
        int scroll_frame = 0;

        while(true)
        {
		//just to be safe
            if(parent != null)									//comment out or edit
            {												//comment out or edit
		    animal = (Animal)parent.animals[parent.choice.getSelectedIndex()];	//comment out or edit
		    message = animal.getMessage();							//comment out or edit
            }												//comment out or edit
            drawNextFrame(scroll_frame);
            repaint();
            scroll_frame++;
            if (scroll_frame > scroll_frames)
            {
                scroll_frame = 0;
            }
            try
            {
                Thread.sleep(sleepTime);
            }
            catch (InterruptedException e) { }
        }
    }
}

the original code that works in spite of its terrible design

/*
 * farm.java
 *
 * Created on May 30, 2000, 9:39 AM
 */
import java.awt.*; 
import java.awt.event.*; 
import java.applet.*; 


/** 
 *
 * @author  frontoffice
 * @version 
 */
public class Farm extends java.applet.Applet implements ItemListener {
  Animals an;
  Text text;
  Thread runner = null;
  public static int selection;
  /** Initializes the applet farm */
  public void init () {
    selection = 6;
    an = new Animals(this);
    text = new Text();
    initComponents ();
    picts.add("sheep.jpg");
    picts.add("dog.gif");
    picts.add("bird.jpg");
    picts.add("cow.jpg");
    picts.add("rooster.jpg");
    picts.add("donkey.jpg");
    add(BorderLayout.SOUTH,text);
    add(BorderLayout.CENTER,an);
    picts.addItemListener(this);
  }

  /** This method is called from within the init() method to
   * initialize the form.
   * WARNING: Do NOT modify this code. The content of this method is
   * always regenerated by the FormEditor.
   */
  private void initComponents () {//GEN-BEGIN:initComponents
    picts = new java.awt.Choice ();
    setLayout (new java.awt.BorderLayout ());
    setBackground(Color.green);
    picts.setFont (new java.awt.Font ("Dialog", 0, 11));
    picts.setBackground (java.awt.Color.white);
    picts.setForeground (java.awt.Color.black);


    add (picts, java.awt.BorderLayout.WEST);

  }//GEN-END:initComponents


  // Variables declaration - do not modify//GEN-BEGIN:variables
  private java.awt.Choice picts;
  // End of variables declaration//GEN-END:variables

  synchronized public void itemStateChanged(final java.awt.event.ItemEvent p1) {
    selection = picts.getSelectedIndex();
     Image im = this.getImage(this.getDocumentBase(),picts.getSelectedItem()); 
  an.updateImage(im); 
  }
  public void start() {
    if (runner == null) {
      runner = new Thread(text);
      runner.start();
    }
    else if (runner.isAlive()) {
      runner.resume();
    }
  }
  public void stop() {
    if (runner.isAlive())
    runner.suspend();
  }
  public void destroy() {
    if (runner.isAlive()) {
      runner.stop();
      runner = null;
    }
  }
  
}  
class Animals extends Canvas implements MouseListener {
  Image im;
  AudioClip sheep;
  AudioClip dog;
  AudioClip bird;
  AudioClip cow;
  AudioClip rooster;
  AudioClip donkey;
 public Animals(Farm newHome) {
  addMouseListener(this);
  Farm fm = newHome;
  sheep = fm.getAudioClip(fm.getDocumentBase(),"sheep.au");
  dog = fm.getAudioClip(fm.getDocumentBase(),"dog.au");
  bird = fm.getAudioClip(fm.getDocumentBase(),"bird.au");
  cow = fm.getAudioClip(fm.getDocumentBase(),"cow.au");
  rooster = fm.getAudioClip(fm.getDocumentBase(),"rooster.au");
  donkey = fm.getAudioClip(fm.getDocumentBase(),"donkey.au");
 }
 synchronized public void paint(Graphics g) 
 { 
  if (im != null) 
   g.drawImage(im,0,0,this); 
 }
 public void updateImage(Image im) 
 { 
  this.im = im; 
  repaint(); 
 }
 public void mouseReleased(final java.awt.event.MouseEvent p1) {
 }
 public void mouseEntered(final java.awt.event.MouseEvent p1) {
  this.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR)); 
 }
 public void mouseClicked(final java.awt.event.MouseEvent p1) {
 }
 public void mousePressed(final java.awt.event.MouseEvent p1) {
  switch(Farm.selection) {
    case 0:
      sheep.play();
      break;
    case 1:
      dog.play();
      break;
    case 2:
      bird.play();
      break;
    case 3:
      cow.play();
      break;
    case 4:
      rooster.play();
      break;
    case 5:
      donkey.play();
    }  
 }
 public void mouseExited(final java.awt.event.MouseEvent p1) {
  setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR)); 
 }
}
class Text extends Canvas implements Runnable {
  String message = "Select an animal";
  int message_x, message_y = 16;
  int min_x, max_x;
  int scroll_frames = 100;
  int sleepTime = 100;
  Image OSC = null;
  Graphics OSC_graphics;
  int width = 400;
  int height = 20;
  public Text() {
    setSize(400,20);
  }
  synchronized public void paint(Graphics g) {
      if (OSC != null)  // if off-screen image exists, copy it to screen
          g.drawImage(OSC,0,0,this);
      else {  // otherwise, fill the canvas with the background color
          g.setColor(getBackground());
          g.fillRect(0,0,size().width,size().height);
      }
   }
       
   public void update(Graphics g) {
         // redefine update() so that it doesn't erase the applet;
         // this will avoid flickering when the applet is redrawn
      paint(g);
   }
   synchronized void drawNextFrame(int scroll_frame) {
    OSC = createImage(width,height);
    OSC_graphics = OSC.getGraphics();
    Font font = getFont();
    font = new Font("TimesRoman",Font.PLAIN,15
    
    
    
    );
    OSC_graphics.setFont(font);
    FontMetrics fm = getFontMetrics(font);
    min_x = -fm.stringWidth(message);
    max_x = width;
    message_x = max_x - ((scroll_frame * (max_x-min_x)) / scroll_frames);
    OSC_graphics.setColor(Color.white);
    OSC_graphics.fillRect(0,0,width,height);
    OSC_graphics.setColor(Color.black);
    OSC_graphics.drawString(message,message_x,message_y);
  }
  public void run() {
    int scroll_frame = 0;
    while(true) {
      switch(Farm.selection) {
        case 0:
          message = "Click the sheep";
          break;
        case 1:
          message = "Click the dog";
          break;
        case 2:
          message = "Click the bird";
          break;
        case 3:
          message = "Click the cow";
          break;
        case 4:
          message = "Click the rooster";
          break;
        case 5:
          message = "Click the donkey";
        }
      drawNextFrame(scroll_frame);
      repaint();
      scroll_frame++;
      if (scroll_frame > scroll_frames)
        scroll_frame = 0;
      try { Thread.sleep(sleepTime); }
      catch (InterruptedException e) { }
    }
  }

[Randall Twede]

i found the problem. i forgot to start the thread.