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 import gov.nasa.worldwind.WorldWind;
  10
  11 import java.beans.*;
  12
  13 /**
  14  * @author dcollins
  15  * @version $Id: KeyPollTimer.java 3704 2007-12-04 17:49:12Z tgaskins $
  16  */
  17 class KeyPollTimer implements java.awt.event.KeyListener
  18 {
  19     private java.util.Timer timer;
  20     private java.util.TimerTask timerTask;
  21     private final int period;
  22     private final java.awt.event.ActionListener listener;
  23     private java.util.ArrayList<Integer> keys = new java.util.ArrayList<Integer>();
  24     private java.util.Stack<Integer> keyStack = new java.util.Stack<Integer>();
  25     private int modifiers;
  26
  27     public KeyPollTimer(int period, java.util.Collection<Integer> keys, java.awt.event.ActionListener listener)
  28     {
  29         if (period < 0)
  30         {
  31             String message = Logging.getMessage("Awt.KeyPollTimer.PeriodLessThanZero");
  32             Logging.logger().severe(message);
  33             throw new IllegalArgumentException(message);
  34         }
  35         if (keys == null)
  36         {
  37             String message = Logging.getMessage("nullValue.CollectionIsNull");
  38             Logging.logger().severe(message);
  39             throw new IllegalArgumentException(message);
  40         }
  41         this.timer = new java.util.Timer();
  42         this.period = period;
  43         this.listener = listener;
  44         this.keys.addAll(keys);
  45
  46         WorldWind.addPropertyChangeListener(WorldWind.SHUTDOWN_EVENT, new PropertyChangeListener()
  47         {
  48             public void propertyChange(PropertyChangeEvent propertyChangeEvent)
  49             {
  50                 KeyPollTimer.this.timer.cancel();
  51                 KeyPollTimer.this.timer = null;
  52             }
  53         });
  54     }
  55
  56     public synchronized boolean isRunning()
  57     {
  58         return this.timerTask != null;
  59     }
  60
  61     public void keyTyped(java.awt.event.KeyEvent e)
  62     {
  63     }
  64
  65     public void keyPressed(java.awt.event.KeyEvent e)
  66     {
  67         if (e == null)
  68             return;
  69
  70         if (this.onKeyEvent(e))
  71         {
  72             if (this.timerTask == null)
  73                 this.start();
  74         }
  75     }
  76
  77     public void keyReleased(java.awt.event.KeyEvent e)
  78     {
  79         if (e == null)
  80             return;
  81
  82         if (this.onKeyEvent(e))
  83         {
  84             if (this.timerTask != null && this.keyStack.empty())
  85                 this.stop();
  86         }
  87     }
  88
  89     private synchronized boolean onKeyEvent(java.awt.event.KeyEvent e)
  90     {
  91         this.modifiers = e.getModifiersEx();
  92
  93         Integer keyCode = e.getKeyCode();
  94         if (this.keys.contains(keyCode))
  95         {
  96             if (this.keyStack.contains(keyCode))
  97                 this.keyStack.remove(keyCode);
  98             if (e.getID() == java.awt.event.KeyEvent.KEY_PRESSED)
  99                 this.keyStack.push(keyCode);
 100             return true;
 101         }
 102
 103         return false;
 104     }
 105
 106     public synchronized void start()
 107     {
 108         if (this.timerTask == null)
 109         {
 110             this.timerTask = new java.util.TimerTask()
 111             {
 112                 public void run()
 113                 {
 114                     long time = System.currentTimeMillis();
 115                     if (time - this.scheduledExecutionTime() >= 2 * KeyPollTimer.this.period)
 116                         return;
 117                     KeyPollTimer.this.updateAndNotify(KeyPollTimer.this.listener);
 118                 }
 119             };
 120             this.timer.schedule(timerTask, 0, this.period);
 121         }
 122     }
 123
 124     public synchronized void stop()
 125     {
 126         if (this.timerTask != null)
 127         {
 128             this.timerTask.cancel();
 129             this.timerTask = null;
 130         }
 131     }
 132
 133     private synchronized void updateAndNotify(java.awt.event.ActionListener listener)
 134     {
 135         if (listener == null)
 136             return;
 137         if (this.keyStack.empty())
 138             return;
 139         listener.actionPerformed(new java.awt.event.ActionEvent(keyStack.peek(), 0, null, modifiers));
 140     }
 141 }