package org.paneris.bibliomania.metasearch.util;

 public class TimeoutThread extends Thread {

   private Thread t;

   private int limitMillis, checkMillis, graceMillis;

   public static class ForcedStopException extends RuntimeException {

     private static final long serialVersionUID = 1L;

   }

   /**

    * @param t Thread to decorate

    * @param limitMillis maximum length of time thread may execute for 

    * @param checkMillis time given to thread to die after being interrupted

    * @param graceMillis a little while longer before kill thread

    */

   public TimeoutThread(Thread t,

                        int limitMillis, int checkMillis, int graceMillis) {

     t.checkAccess();

     this.t = t;

     this.limitMillis = limitMillis;

     this.checkMillis = checkMillis;

     this.graceMillis = graceMillis;

     setDaemon(true);

   }

   public TimeoutThread(Thread t, int limitMillis) {

     this(t, limitMillis, 100, 1000);

   }

   public void run() {

     try {

       Thread.sleep(limitMillis);

       t.interrupt();

       Thread.sleep(checkMillis);

       if (t.isAlive()) {

         Thread.sleep(graceMillis);

         t.stop(new ForcedStopException());

       }

     }

     catch (InterruptedException e) {

     }

   }

   public static TimeoutThread forCurrentThread(int limitMillis) {

     TimeoutThread timer = new TimeoutThread(Thread.currentThread(),

                                             limitMillis);

     timer.start();

     return timer;

   }

   public static void run(Runnable r, int limitMillis) {

     TimeoutThread timer = forCurrentThread(limitMillis);

     try {

       r.run();

     }

     finally {

       timer.stop();

     }

   }

 }