/* file PhilosopherArea.java */

import java.awt.*;

public class PhilosopherArea extends Canvas {
    PhilAnimator controller;
    Image[] imgs = new Image[3];
    Chopstick[] chopsticks = new Chopstick[NUMPHILS];
    String[] names = { "Arisduktle" ,
		       "Dukrates",
		       "Pythagorduke",
		       "Duko",
		       "Dukimedes" };
    static final int NUMPHILS = 5;

    private static final double MARGIN = 10.0f;
    private double spacing;
    private Philosopher[] philosophers = new Philosopher[NUMPHILS];
    private boolean[] redraw = new boolean[NUMPHILS];

    private boolean running = false;

    public PhilosopherArea(PhilAnimator controller) {
        super();
        this.controller = controller;

        MediaTracker mt;
        mt = new MediaTracker(this);

        imgs[0] = controller.getImage(controller.getCodeBase(),
				      "hungryduke.gif");
        mt.addImage(imgs[0], 0);
        imgs[1] = controller.getImage(controller.getCodeBase(),
				      "rightspoonduke.gif");
        mt.addImage(imgs[1], 1);
        imgs[2] = controller.getImage(controller.getCodeBase(),
				      "bothspoonsduke.gif");
        mt.addImage(imgs[2], 2);

        try {
            mt.waitForID(0);
            mt.waitForID(1);
            mt.waitForID(2);
        } catch (java.lang.InterruptedException e) {
            System.out.println("Couldn't load one of the images");
        }

        spacing = imgs[0].getWidth(this) + MARGIN;
        createPhilosophersAndChopsticks();
    }

    public void paint(Graphics g) {
        g.setColor(Color.lightGray);
        g.fillRect(0, 0, size().width, size().height);
        for (int i = 0; i < NUMPHILS; i++) {
            redraw[i] = true;
        }
        update(g);
    }

    public void update(Graphics g) {
        for (int i = 0; i < NUMPHILS; i++) {
            if (redraw[i]) {
                philosophers[i].paint(g);
                redraw[i] = false;
            }
        }
    }

    public boolean mouseDown(java.awt.Event evt, int x, int y) {
        if (running) {
            for (int i = 0; i < NUMPHILS; i++)
                philosophers[i].suspend();
        } else {
            for (int i = 0; i < NUMPHILS; i++)
                philosophers[i].resume();
        }

        running = !running;
        return true;
    }

    public synchronized void repaintPhil(int id) {
        redraw[id] = true;
        repaint();
    }

    public void startPhilosophers() {
        for (int i = 0; i < NUMPHILS; i++)
            philosophers[i].start();
        running = true;
    }

    public void stopPhilosophers() {
        for (int i = 0; i < NUMPHILS; i++)
            philosophers[i].stopRequested();
    }

    public void createPhilosophersAndChopsticks() {
        double x, y;
        double radius = 80.0;
        double centerAdj = 85.0;
        double radians;

/* for a straight line
        y = MARGIN;
*/
        for (int i = 0; i < NUMPHILS; i++)
            chopsticks[i] = new Chopstick();

        for (int i = 0; i < NUMPHILS; i++) {
/* for a straight line
            x = i * spacing;
*/
            radians = i*(2.0 * Math.PI /(double)NUMPHILS);
            x = Math.sin(radians) * radius + centerAdj; 
            y = Math.cos(radians) * radius + centerAdj; 
            philosophers[i] = new Philosopher(this, x, y, i);
            repaintPhil(i);   
        }
    }
}

_________________________________________________________________

/* file PhilAnimator.java */

import java.awt.*;

public class PhilAnimator extends java.applet.Applet {

    private Button stopStartButton = new Button("start");

    // delays can go from 500 to 10,000
    // (they get multiplied by 100 in Philosopher
    Scrollbar grabDelaySlider = new Scrollbar(Scrollbar.HORIZONTAL,
					      5, 100, 0, 100);
    private Label label = new Label("  500 milliseconds");
    private FramedArea framedArea;

    public void init() {
        GridBagLayout gridBag = new GridBagLayout();
        GridBagConstraints c = new GridBagConstraints();

        setLayout(gridBag);

        framedArea = new FramedArea(this);
        c.fill = GridBagConstraints.BOTH;
        c.weighty = 1.0;
        c.gridwidth = GridBagConstraints.REMAINDER; //end row
        gridBag.setConstraints(framedArea, c);
        add(framedArea);

        c.fill = GridBagConstraints.HORIZONTAL;
        c.weightx = 1.0;
        c.weighty = 0.0;
        gridBag.setConstraints(stopStartButton, c);
        add(stopStartButton);


        c.gridwidth = GridBagConstraints.RELATIVE; //don't end row
        c.weightx = 1.0;
        c.weighty = 0.0;
        gridBag.setConstraints(grabDelaySlider, c);
        add(grabDelaySlider);

        c.weightx = 0.0;
        c.gridwidth = GridBagConstraints.REMAINDER; //end row
        gridBag.setConstraints(label, c);
        add(label);

        validate();
    }

    public boolean handleEvent(Event e) {
        if (e.target == stopStartButton) {
            if (stopStartButton.getLabel().equals("stop/reset")) {
                framedArea.stopButton();
                stopStartButton.setLabel("start");
            } else if (stopStartButton.getLabel().equals("start")) {
                framedArea.startButton();
                stopStartButton.setLabel("stop/reset");
            }
        } else if (e.target == grabDelaySlider) {
            label.setText(String.valueOf(100*grabDelaySlider.getValue()) + 
				         " milliseconds");
        }
        return false;
    }
}

_________________________________________________________________

/* file Philosopher.java */

import java.awt.*;

public class Philosopher extends Thread {
    private Chopstick leftStick, rightStick;
    private double x, y;
    private boolean sated;
    private PhilosopherArea parent;
    private int position;
    private boolean stopRequested = false;

    public Philosopher(PhilosopherArea parent,
		       double x, double y, int position) {
        super(parent.names[position]);

        this.parent = parent;
        this.position = position;
        this.x = x;
        this.y = y;

        // identify the chopsticks to my right and left
        this.rightStick = this.parent.chopsticks[position];
        if (position == 0) {
            this.leftStick = this.parent.chopsticks[this.parent.NUMPHILS-1];
        } else {
            this.leftStick = this.parent.chopsticks[position-1];
        }

        // I'm hungry
        this.sated = false;
    }

    public void run() {
        int grabDelay;
        while (stopRequested == false) {
             try {
                grabDelay = parent.controller.grabDelaySlider.getValue() * 100;
                sleep((int)(Math.random() * grabDelay));
                rightStick.grab(this);
                parent.repaintPhil(position);

                grabDelay = parent.controller.grabDelaySlider.getValue() * 100;
                sleep((int)(Math.random() * grabDelay));
                leftStick.grab(this);
                parent.repaintPhil(position);

                grabDelay = parent.controller.grabDelaySlider.getValue() * 100;
                sleep((int)(Math.random() * grabDelay));
                eat();

                grabDelay = parent.controller.grabDelaySlider.getValue() * 100;
                sleep((int)(Math.random() * grabDelay * 4));
                sated = false;
                parent.repaintPhil(position);
            } catch (java.lang.InterruptedException e) {
            }
        }
    }

    public void eat() {
        rightStick.release(this);
        leftStick.release(this);
        sated = true;
        parent.repaintPhil(position);
    }

    public void paint(Graphics g) {
        g.setColor(Color.lightGray);
        g.fillRect((int)x, (int)y, parent.imgs[0].getWidth(parent),
		   parent.imgs[0].getHeight(parent)+25);
        if (sated == false) {
            if (rightStick.owner == this && leftStick.owner != this) {
		// got left only
                g.drawImage(parent.imgs[1], (int)x, (int)y, parent);
            } else if (rightStick.owner == this && leftStick.owner == this) {
		// got both
                g.drawImage(parent.imgs[2], (int)x, (int)y, parent);
            } else {
		// got nothing
                g.drawImage(parent.imgs[0], (int)x, (int)y, parent);
            }
        } else {
            g.drawImage(parent.imgs[0], (int)x, (int)y, parent);
            g.setColor(Color.black);
            g.drawString("Mmm!", ((int)(x)+8),
			 ((int)(y)+parent.imgs[0].getHeight(parent)+13));
        }
    }
    public void stopRequested() {
        stopRequested = true;
    }
}