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

public class HelloWeb4 extends Applet implements Runnable {
  int messageX = 125, messageY = 95;
  String theMessage;
  Button theButton;
  Color[] someColors = {
    Color.black, Color.red, Color.green, Color.blue, Color.yellow };
  int colorIndex = 0;
  Thread blinkThread;
  boolean blinkState;

  public void init() {
    theMessage = getParameter("message");
    theButton = new Button("Change Color");
    add(theButton);
  }

  public void paint(Graphics gc) {
    gc.setColor(blinkState ? Color.white : currentColor());
    gc.drawString(theMessage, messageX, messageY);
  }

  public boolean action(Event e, Object arg) {
    if (e.target == theButton) {
      changeColor();
      return true;
    }
    return false;
  }

  public boolean mouseDrag(Event evt, int x, int y) {
    messageX = x;
    messageY = y;
    repaint();
    return true;
  }

  synchronized private Color currentColor() {
    return someColors[colorIndex];
  }

  synchronized private void changeColor() {
    if (++colorIndex == someColors.length)
      colorIndex = 0;
    theButton.setForeground(currentColor());
    repaint();
  }

  public void run() {
    while ( true ) {
      blinkState = !blinkState;
      repaint();
      try {
        Thread.sleep(500);
      }
      catch(InterruptedException e) {
      }
    }
  }

  public void start() {
    if ( blinkThread == null ) {
      blinkThread = new Thread(this);
      blinkThread.start();
    }
  }

  public void stop() {
    if ( blinkThread != null ) {
      blinkThread.stop();
      blinkThread = null;
    }
  }
}