gov/nasa/worldwind/awt/KeyPollTimer.java

   1 /*
   2 Copyright (C) 2001, 2006 United States Government as represented by
   3 the Administrator of the National Aeronautics and Space Administration.
   4 All Rights Reserved.
   5 */
   6 package gov.nasa.worldwind.awt;
   7
   8 import gov.nasa.worldwind.util.Logging;
   9
  10 /**
  11  * @author dcollins
  12  * @version $Id: KeyPollTimer.java 2471 2007-07-31 21:50:57Z tgaskins $
  13  */
  14 class KeyPollTimer implements java.awt.event.KeyListener
  15 {
  16     private java.util.Timer timer;
  17     private java.util.TimerTask timerTask;
  18     private final int period;
  19     private final java.awt.event.ActionListener listener;
  20     private java.util.ArrayList<Integer> keys = new java.util.ArrayList<Integer>();
  21     private java.util.Stack<Integer> keyStack = new java.util.Stack<Integer>();
  22     private int modifiers;
  23
  24     public KeyPollTimer(int period, java.util.Collection<Integer> keys, java.awt.event.ActionListener listener)
  25     {
  26         if (period < 0)
  27         {
  28             String message = Logging.getMessage("Awt.KeyPollTimer.PeriodLessThanZero");
  29             Logging.logger().severe(message);
  30             throw new IllegalArgumentException(message);
  31         }
  32         if (keys == null)
  33         {
  34             String message = Logging.getMessage("nullValue.CollectionIsNull");
  35             Logging.logger().severe(message);
  36             throw new IllegalArgumentException(message);
  37         }
  38         this.timer = new java.util.Timer();
  39         this.period = period;
  40         this.listener = listener;
  41         this.keys.addAll(keys);
  42     }
  43
  44     public synchronized boolean isRunning()
  45     {
  46         return this.timerTask != null;
  47     }
  48
  49     public void keyTyped(java.awt.event.KeyEvent e)
  50     {
  51     }
  52
  53     public void keyPressed(java.awt.event.KeyEvent e)
  54     {
  55         if (e == null)
  56             return;
  57
  58         if (this.onKeyEvent(e))
  59         {
  60             if (this.timerTask == null)
  61                 this.start();
  62         }
  63     }
  64
  65     public void keyReleased(java.awt.event.KeyEvent e)
  66     {
  67         if (e == null)
  68             return;
  69
  70         if (this.onKeyEvent(e))
  71         {
  72             if (this.timerTask != null && this.keyStack.empty())
  73                 this.stop();
  74         }
  75     }
  76
  77     private synchronized boolean onKeyEvent(java.awt.event.KeyEvent e)
  78     {
  79         this.modifiers = e.getModifiersEx();
  80
  81         Integer keyCode = e.getKeyCode();
  82         if (this.keys.contains(keyCode))
  83         {
  84             if (this.keyStack.contains(keyCode))
  85                 this.keyStack.remove(keyCode);
  86             if (e.getID() == java.awt.event.KeyEvent.KEY_PRESSED)
  87                 this.keyStack.push(keyCode);
  88             return true;
  89         }
  90
  91         return false;
  92     }
  93
  94     public synchronized void start()
  95     {
  96         if (this.timerTask == null)
  97         {
  98             this.timerTask = new java.util.TimerTask()
  99             {
 100                 public void run()
 101                 {
 102                     long time = System.currentTimeMillis();
 103                     if (time - this.scheduledExecutionTime() >= 2 * KeyPollTimer.this.period)
 104                         return;
 105                     KeyPollTimer.this.updateAndNotify(KeyPollTimer.this.listener);
 106                 }
 107             };
 108             this.timer.schedule(timerTask, 0, this.period);
 109         }
 110     }
 111
 112     public synchronized void stop()
 113     {
 114         if (this.timerTask != null)
 115         {
 116             this.timerTask.cancel();
 117             this.timerTask = null;
 118         }
 119     }
 120
 121     private synchronized void updateAndNotify(java.awt.event.ActionListener listener)
 122     {
 123         if (listener == null)
 124             return;
 125         if (this.keyStack.empty())
 126             return;
 127         listener.actionPerformed(new java.awt.event.ActionEvent(keyStack.peek(), 0, null, modifiers));
 128     }
 129 }