toolkit/test/accessibility/EventQueue.java

   1 /*
   2  * This file is part of the LibreOffice project.
   3  *
   4  * This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this
   6  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   7  *
   8  * This file incorporates work covered by the following license notice:
   9  *
  10  *   Licensed to the Apache Software Foundation (ASF) under one or more
  11  *   contributor license agreements. See the NOTICE file distributed
  12  *   with this work for additional information regarding copyright
  13  *   ownership. The ASF licenses this file to you under the Apache
  14  *   License, Version 2.0 (the "License"); you may not use this file
  15  *   except in compliance with the License. You may obtain a copy of
  16  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  17  */
  18
  19 import java.util.LinkedList;
  20
  21 /** The event queue singleton dispatches events received from OpenOffice.org
  22     applications in a thread separate from the AWB main thread.
  23
  24     The queue of event objects, LinkedList<Runnable> The queue object will
  25     also serve as lock for the consumer/producer type synchronization.
  26 */
  27 class EventQueue
  28     implements Runnable
  29 {
  30     private boolean mbVerbose = false;
  31     private boolean mbHandleDisposingEventsSynchronous = true;
  32
  33     public synchronized static EventQueue Instance ()
  34     {
  35         if (maInstance == null)
  36             maInstance = new EventQueue ();
  37         return maInstance;
  38     }
  39
  40     public void addEvent (Runnable aEvent)
  41     {
  42         synchronized (maMonitor)
  43         {
  44             if (mbVerbose)
  45                 System.out.println ("queueing regular event " + aEvent);
  46             maRegularQueue.addLast (aEvent);
  47             maMonitor.notify ();
  48         }
  49     }
  50
  51
  52     public void addDisposingEvent (Runnable aEvent)
  53     {
  54         if (mbHandleDisposingEventsSynchronous)
  55             aEvent.run ();
  56         else
  57             synchronized (maMonitor)
  58             {
  59                 if (mbVerbose)
  60                     System.out.println ("queueing disposing event " + aEvent);
  61                 maDisposingQueue.addLast (aEvent);
  62                 maMonitor.notify ();
  63             }
  64     }
  65
  66
  67     private EventQueue ()
  68     {
  69         maRegularQueue = new LinkedList<Runnable>();
  70         maDisposingQueue = new LinkedList<Runnable>();
  71         new Thread(this, "AWB.EventQueue").start();
  72     }
  73
  74
  75     /// This thread's main method: deliver all events
  76     public void run()
  77     {
  78         // in an infinite loop, check for events to deliver, then
  79         // wait on lock (which will be notified when new events arrive)
  80         while( true )
  81         {
  82             Runnable aEvent = null;
  83             do
  84             {
  85                 synchronized (maMonitor)
  86                 {
  87                     if (maDisposingQueue.size() > 0)
  88                     {
  89                         aEvent = maDisposingQueue.removeFirst();
  90                         if (mbVerbose)
  91                             System.out.println ("delivering disposing event " + aEvent);
  92                     }
  93                     else if (maRegularQueue.size() > 0)
  94                     {
  95                         aEvent = maRegularQueue.removeFirst();
  96                         if (mbVerbose)
  97                             System.out.println ("delivering regular event " + aEvent);
  98                     }
  99                     else
 100                         aEvent = null;
 101                 }
 102                 if (aEvent != null)
 103                 {
 104                     try
 105                     {
 106                         aEvent.run();
 107                     }
 108                     catch( Throwable e )
 109                     {
 110                         System.out.println(
 111                             "caught exception during event delivery: " + e );
 112                         e.printStackTrace();
 113                     }
 114                 }
 115             }
 116             while( aEvent != null );
 117
 118             try
 119             {
 120                 synchronized (maMonitor)
 121                 {
 122                     maMonitor.wait();
 123                 }
 124             }
 125             catch (Exception e)
 126             {
 127                 // can't wait? odd!
 128                 System.err.println("Can't wait!");
 129                 e.printStackTrace();
 130             }
 131         }
 132     }
 133
 134     private static EventQueue maInstance = null;
 135     private final Object maMonitor = new Object();
 136     private final LinkedList<Runnable> maRegularQueue;
 137     private final LinkedList<Runnable> maDisposingQueue;
 138 }
 139
 140