www.pudn.com > jnp-src.rar > Alarm.java

/*
 * Java Network Programming, Second Edition
 * Merlin Hughes, Michael Shoffner, Derek Hamner
 * Manning Publications Company; ISBN 188477749X
 *
 * http://nitric.com/jnp/
 *
 * Copyright (c) 1997-1999 Merlin Hughes, Michael Shoffner, Derek Hamner;
 * all rights reserved; see license.txt for details.
 */

public class Alarm implements Runnable { 
  public Alarm (int time, Alarmable target) { 
    this (time, target, null); 
  } 
 
  protected Alarmable target; 
  protected Object arg; 
  protected int time; 
  public Alarm (int time, Alarmable target, Object arg) { 
    this.time = time; 
    this.target = target; 
    this.arg = arg; 
  } 
 
  protected Thread alarm; 
  public synchronized void start () { 
    if (alarm == null) { 
      alarm = new Thread (this); 
      alarm.start (); 
    } 
  } 
 
  public synchronized void stop () { 
    if (alarm != null) { 
      alarm.interrupt (); 
      alarm = null; 
    } 
  } 
 
  public void run () { 
    try { 
      Thread.sleep (time); 
      synchronized (this) { 
        if (Thread.interrupted ()) 
          return; 
        alarm = null; 
      } 
      target.alarmCall (arg); 
    } catch (InterruptedException ignored) { 
    } 
  } 
}