odk/examples/DevelopersGuide/Accessibility/RegistrationThread.java

   1 /*************************************************************************
   2  *
   3  *  $RCSfile: RegistrationThread.java,v $
   4  *
   5  *  $Revision: 1.3 $
   6  *
   7  *  last change: $Author: hr $ $Date: 2003-06-30 15:07:21 $
   8  *
   9  *  The Contents of this file are made available subject to the terms of
  10  *  the BSD license.
  11  *
  12  *  Copyright (c) 2003 by Sun Microsystems, Inc.
  13  *  All rights reserved.
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  15  *  Redistribution and use in source and binary forms, with or without
  16  *  modification, are permitted provided that the following conditions
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  19  *     notice, this list of conditions and the following disclaimer.
  20  *  2. Redistributions in binary form must reproduce the above copyright
  21  *     notice, this list of conditions and the following disclaimer in the
  22  *     documentation and/or other materials provided with the distribution.
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  24  *     contributors may be used to endorse or promote products derived
  25  *     from this software without specific prior written permission.
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  39  *************************************************************************/
  40
  41 import java.awt.event.ActionListener;
  42 import javax.swing.*;
  43 import java.awt.*;
  44 import java.util.*;
  45
  46 import com.sun.star.awt.XTopWindowListener;
  47 import com.sun.star.uno.UnoRuntime;
  48 import com.sun.star.bridge.XUnoUrlResolver;
  49 import com.sun.star.lang.XMultiServiceFactory;
  50 import com.sun.star.accessibility.*;
  51 import com.sun.star.awt.XExtendedToolkit;
  52
  53 /** This class is used as a thread and registers or unregsiters a listener
  54     given the constructor at all nodes of a tree of accessibility objects.
  55 */
  56 public class RegistrationThread
  57     implements Runnable
  58 {
  59     /** Start a new thread that adds or removes the given listener at all
  60         accessible objects in the sub-tree rooted in the given accessible
  61         object.
  62         @param aListener
  63             The listener that is added or removed.
  64         @param xRoot
  65             The root of the sub-tree of accessibility objects.
  66         @param bRegister
  67             This flag decides whether to add or remove the listener.
  68     */
  69     public RegistrationThread (
  70         EventListenerProxy aListener,
  71         XAccessibleContext xRoot,
  72         boolean bRegister,
  73         boolean bShowMessages)
  74     {
  75         maListener = aListener;
  76         mxRoot = xRoot;
  77         mbRegister = bRegister;
  78         mbShowMessages = bShowMessages;
  79
  80         if (mxRoot != null)
  81         {
  82             if (mbShowMessages)
  83                 MessageArea.println ("starting to register at " + mxRoot.getAccessibleName());
  84             new Thread (this, "RegistrationThread").start();
  85         }
  86     }
  87
  88
  89
  90     public void run ()
  91     {
  92         System.out.println ("starting registration");
  93         long nNodeCount = traverseTree (mxRoot);
  94         System.out.println ("ending registration");
  95         if (mbShowMessages)
  96         {
  97             if ( ! mbRegister)
  98                 MessageArea.print ("un");
  99             MessageArea.println ("registered at " + nNodeCount
 100                 + " objects in accessibility tree of " + mxRoot.getAccessibleName());
 101         }
 102     }
 103
 104
 105
 106
 107     /** Register this object as listener for accessibility events at all nodes
 108         of the given tree.
 109         @param xRoot
 110             The root node of the tree at which to register.
 111     */
 112     public long traverseTree (XAccessibleContext xRoot)
 113     {
 114         long nNodeCount = 0;
 115         if (xRoot != null)
 116         {
 117             // Register the root node.
 118             XAccessibleEventBroadcaster xBroadcaster =
 119                 (XAccessibleEventBroadcaster) UnoRuntime.queryInterface (
 120                     XAccessibleEventBroadcaster.class,
 121                     xRoot);
 122             if (xBroadcaster != null)
 123             {
 124                 if (mbRegister)
 125                     xBroadcaster.addEventListener (maListener);
 126                 else
 127                     xBroadcaster.removeEventListener (maListener);
 128                 nNodeCount += 1;
 129             }
 130
 131             // Call this method recursively to register all sub-trees.
 132             try
 133             {
 134                 int nChildCount = xRoot.getAccessibleChildCount();
 135                 for (int i=0; i<nChildCount; i++)
 136                 {
 137                     XAccessible xChild = xRoot.getAccessibleChild (i);
 138                     if (xChild != null)
 139                         nNodeCount += traverseTree (xChild.getAccessibleContext());
 140                 }
 141             }
 142             catch (com.sun.star.lang.IndexOutOfBoundsException aException)
 143             {
 144                 // The set of children has changed since our last call to
 145                 // getAccesibleChildCount().  Don't try any further on this
 146                 // sub-tree.
 147             }
 148             catch (com.sun.star.lang.DisposedException aException)
 149             {
 150                 // The child has been destroyed since our last call to
 151                 // getAccesibleChildCount().  That is OK. Don't try any
 152                 // further on this sub-tree.
 153             }
 154         }
 155         return nNodeCount;
 156     }
 157
 158     private EventListenerProxy maListener;
 159     private XAccessibleContext mxRoot;
 160     private boolean mbRegister;
 161     private boolean mbShowMessages;
 162 }