/** A template to control the state of a thread through setting
 *  an internal flag.
 *
 *  Taken from Core Web Programming from 
 *  Prentice Hall and Sun Microsystems Press,
 *  http://www.corewebprogramming.com/.
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted. 
 */

public class StoppableThread extends Thread {

   public static final int STOP    = 0;
   public static final int RUN     = 1;
   public static final int WAIT    = 2;
   private int state = RUN;

  /** Public method to permit setting a flag to stop or
   *  suspend the thread.  The state is monitored through the
   *  corresponding checkState method.
   */

   public synchronized void setState(int state) {
      this.state = state;
      if (state==RUN) {
         notify();
      }
   }

  /** Returns the desired state of the thread (RUN, STOP, WAIT).
   *  Normally, you may want to change the state or perform some
   *  other task if an InterruptedException occurs.
   */

   private synchronized int checkState() {
      while (state==WAIT) {
        try {
          wait();
        } catch (InterruptedException e) { }
      }
      return state;
   }

  /** An example of thread that will continue to run until
   *  the creating object tells the thread to STOP.
   */

   public void run() {
      while (checkState()!=STOP) {
         ...
      }
   }
}