Code example of the day, want your advice

Question

Update: I have removed the setRunnable method and all the synchronization stuff, which takes care of question a. Now, on part B, can anyone suggest a better name for this class?
I am posting my class ThreadForMultipleAnytimeRuns, plus my Eyes class which was actually the reason I created it.
ThreadForMultipleAnytimeRuns offers the following:
(a) you can run a runnable outside of the GUI thread - important in this case, because if you try to run an animation in the drawing thread you're not going to see anything
(b) It will queue the blinks so they don't all happen at once.
Questions:
1. Is what I've done thread-safe? I added a method to swap the runnable into the class. I have it so that it waits until the job queue (semaphore) is empty before it swaps in the new runnable. Is this safe now? I would love to hear your thoughts
2. I am unsatisfied with the name of this class. Can anyone think of a better name?
BTW, unfortunately this code isn't compilable as posted. To get it to compile, you need to remove the references to MathUtils - all this takes is replacing distance with the euclidean distance formula, and angle with java.lang.Math.atan2, and references to WindowUtilities, which means replacing WindowUtilities.visualize and just building a JFrame and sticking the eyes in it
Thanks for any comments about how I could make this better!
You are welcome to use and modify this code, but please don't change the package or take credit for it as your own code.
package tjacobs.thread;
import java.awt.Dimension;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.concurrent.Semaphore;
import javax.swing.JFrame;
import tjacobs.ui.Eyes;
import tjacobs.ui.WindowUtilities;
public class ThreadForMultipleAnytimeRuns extends Thread {
     private Runnable mRunnable;
     private Semaphore mSemaphore;
     public ThreadForMultipleAnytimeRuns(Runnable arg0) {
          super();
          init(arg0);
     private void init(Runnable r) {
          mRunnable = r;
          mSemaphore = new Semaphore(0);
          setDaemon(true);
     public ThreadForMultipleAnytimeRuns(Runnable arg0, String arg1) {
          super(arg1);
          init(arg0);
     public ThreadForMultipleAnytimeRuns(ThreadGroup arg0, Runnable arg1, String arg2) {
          super(arg0, arg2);
          init(arg1);
     public void run () {
          try {
               while (!isInterrupted()) {
                    // make a local copy so if mRunnable changes
                    // we have the fresh one
                    mSemaphore.acquire();
                    if (getSemaphoreCount() == 0) {
                         Runnable r = mRunnable;
                         synchronized (this) {
                              notifyAll();
                         r.run();
                    mRunnable.run();
          catch (InterruptedException ex) {}
     public void runAgain() {
          mSemaphore.release();
     public void runAgain(int numTimes) {
          mSemaphore.release(numTimes);
     public void stopThread() {
          interrupt();
     public int getSemaphoreCount() {
          return mSemaphore.availablePermits();
     public Runnable getRunnable() {
          return mRunnable;
     public synchronized void setRunnable(Runnable r) {
          if (getSemaphoreCount() > 0) {
               try {
                    wait();
               catch (InterruptedException ex) {
                    return;
          mRunnable = r;
     public static void main(String[] args) {
          final Eyes eyes = new Eyes(true);
          //eyes.addMouseMotionListener(eyes);
          Runnable r = new Runnable() {
               public void run() {
                    eyes.blink();
                    try {
                         Thread.sleep(100);
                    catch(InterruptedException ex) {}
          final ThreadForMultipleAnytimeRuns ar = new ThreadForMultipleAnytimeRuns(r);
          ar.start();
          eyes.addMouseListener(new MouseAdapter() {
               public void mouseClicked(MouseEvent me) {
                    ar.runAgain();
          eyes.setPreferredSize(new Dimension(60,20));
          WindowUtilities.visualize(eyes);
//          JFrame jf = new JFrame();
//          jf.add(eyes);
//          jf.pack();
//          jf.setLocation(100,100);
//          jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//          jf.setVisible(true);
================================================
tjacobs.ui.Eyes
============
package tjacobs.ui;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.JComponent;
import javax.swing.SwingUtilities;
import tjacobs.MathUtils;
public class Eyes extends JComponent implements MouseMotionListener {
     private int mEyeGap = 0;
     private double mEyeDir1 = Double.NaN, mEyeDir2 = Double.NaN;
     private double mEyeRatio = .6;
     private int mBlinkEyesState = 0;
     private Timer mEyeBlinker;
     private long mTimeBetweenBlinks;
     private long mBlinkAnimationSpeed = 100;
     public Eyes() {
          //setBackground(Color.BLACK);
          this(false);
     public Eyes(boolean watchOnEyes) {
          setBackground(Color.PINK);
          setForeground(Color.BLUE);
          if (watchOnEyes) addMouseMotionListener(this);          
     public void setBatAnimationSpeed(long speed) {
          mBlinkAnimationSpeed = speed;
     public long getBatAnimationSpeed() {
          return mBlinkAnimationSpeed;
     public void mouseMoved(MouseEvent me) {
          Point p = SwingUtilities.convertPoint(me.getComponent(), me.getPoint(), this);
          int height = getHeight();
          mEyeDir1 = MathUtils.angle(height / 2, height / 2, p.x, p.y);
          mEyeDir2 = MathUtils.angle((3 * height) / 2 + mEyeGap, height / 2, p.x, p.y);
          repaint();
     public void mouseDragged(MouseEvent me) {
          mouseMoved(me);
     public int getEyeGap() {
          return mEyeGap;
     public void setEyeGap(int gap) {
          mEyeGap = gap;
     public void setBlinkEyes(long timeBetweenBlinks) {
          mTimeBetweenBlinks = timeBetweenBlinks;
          if (mEyeBlinker != null) {
               mEyeBlinker.cancel();
               mEyeBlinker = null;
          if (timeBetweenBlinks < mBlinkAnimationSpeed * 8) {
               return;
          else {
               mEyeBlinker = new Timer(true); //allow it to be a daemon thread
               mEyeBlinker.scheduleAtFixedRate(new BlinkEyesTask(), mTimeBetweenBlinks, mTimeBetweenBlinks);
               //Thread t = new Thread(mEyeBlinkter);
               //t.start();
      * makes the eyes blink
      * this method will not function correctly if it is run in the
      * GUI painter thread, as it handles the whole process and calls
      * repaint() sleep() in between steps.
     public void blink() {
          try {
               //System.out.println("bat");
               Thread t = Thread.currentThread();
               mBlinkEyesState = 1;
               repaint();
               t.sleep(mBlinkAnimationSpeed);
               mBlinkEyesState = 2;
               repaint();
               t.sleep(mBlinkAnimationSpeed);
               mBlinkEyesState = 3;
               repaint();
               t.sleep(mBlinkAnimationSpeed);
               mBlinkEyesState = 4;
               repaint();
               t.sleep(mBlinkAnimationSpeed);
               mBlinkEyesState = 3;
               repaint();
               t.sleep(mBlinkAnimationSpeed);
               mBlinkEyesState = 2;
               repaint();
               t.sleep(mBlinkAnimationSpeed);
               mBlinkEyesState = 1;
               repaint();
               t.sleep(mBlinkAnimationSpeed);
               mBlinkEyesState = 0;
               repaint();
          catch (InterruptedException ex) {
               if (mBlinkEyesState != 0) {
                    mBlinkEyesState = 0;
                    repaint();
     private class BlinkEyesTask extends TimerTask {
          public void run() {
               blink();
      * @param angle Either Double.NaN for center, or a value between 0 and 2 PI
     public void setEye1Direction(double angle) {
          mEyeDir1 = angle;
     public double getEye1Direction() {
          return mEyeDir1;
      * @param angle Either Double.NaN for center, or a value between 0 and 2 PI
     public void setEye2Direction(double angle) {
          mEyeDir1 = angle;
     public double getEye2Direction() {
          return mEyeDir2;
     public void paintComponent(Graphics g) {
          int height = getHeight();
          int r = height / 2;
          g.setColor(Color.WHITE);
          g.fillOval(0, 0, height, height);
          g.fillOval(height + mEyeGap + 0, 0, height, height);
          g.setColor(Color.BLACK);
          g.drawOval(0, 0, height, height);
          g.drawOval(height + mEyeGap + 0, 0, height, height);
          g.setColor(getForeground());
          int irisR = (int) (r * mEyeRatio);
          if (Double.isNaN(mEyeDir1)) {
               int x1 = (r - irisR);
               int y1 = x1;
               g.fillOval(x1, y1, irisR * 2, irisR * 2);
          } else {
               int x1 = (r - irisR);
               int y1 = x1;
               x1 -= Math.cos(mEyeDir1) * (r - irisR);
               y1 -= Math.sin(mEyeDir1) * (r - irisR);
               g.fillOval(x1, y1, irisR * 2, irisR * 2);
          if (Double.isNaN(mEyeDir2)) {
               int x1 = (r - irisR) + height + mEyeGap;
               int y1 = (r - irisR);
               g.fillOval(x1, y1, irisR * 2 , irisR * 2);               
          } else {
               int x1 = (r - irisR) + height + mEyeGap;
               int y1 = r - irisR;
               x1 -= Math.cos(mEyeDir2) * (r - irisR);
               y1 -= Math.sin(mEyeDir2) * (r - irisR);
               g.fillOval(x1, y1, irisR * 2, irisR * 2);
//          OLD
//          if (Double.isNaN(mEyeDir1)) {
//               int x1 = (r - irisR);
//               int y1 = x1;
//               g.fillOval(x1, y1, irisR * 2, irisR * 2);
//               x1 += height + mEyeGap;
//               g.fillOval(x1, y1, irisR * 2 , irisR * 2);               
//          } else {
//               int x1 = (r - irisR);
//               int y1 = x1;
//               x1 -= Math.cos(mEyeDir1) * (r - irisR);
//               y1 -= Math.sin(mEyeDir1) * (r - irisR);
//               g.fillOval(x1, y1, irisR * 2, irisR * 2);
//               x1 = (r - irisR) + height + mEyeGap;
//               y1 = r - irisR;
//               x1 -= Math.cos(mEyeDir2) * (r - irisR);
//               y1 -= Math.sin(mEyeDir2) * (r - irisR);
//               g.fillOval(x1, y1, irisR * 2, irisR * 2);
          //Eye Blinking
          if (mBlinkEyesState != 0) {
               Rectangle rect = new Rectangle(0,0,getWidth(), getHeight() * mBlinkEyesState / 4);
               g.setClip(rect);
               g.setColor(getBackground());
               g.fillOval(0, 0, height, height);
               g.fillOval(height + mEyeGap + 0, 0, height, height);
      * @param args
     public static void main(String[] args) {
          // TODO Auto-generated method stub
          Eyes eyes = new Eyes(true);
          eyes.setBlinkEyes(10000);
          eyes.setPreferredSize(new Dimension(60,25));
          eyes.setEyeGap(5);
          WindowUtilities.visualize(eyes);
}Message was edited by:
tjacobs01

Answer 1

So, if you shake the panel long enough, do the
contents disappear? :Dno but they get a big headache