toolkit/test/accessibility/MessageArea.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.awt.Font;
  20 import java.awt.Color;
  21 import java.awt.Graphics;
  22 import javax.swing.JScrollPane;
  23 import javax.swing.JTextArea;
  24 import javax.swing.JScrollBar;
  25
  26
  27
  28 /** A message area displays text in a scrollable text widget.  It is a
  29     singleton.  Other objects can access it directly to display messages.
  30 */
  31 public class MessageArea
  32     extends JScrollPane
  33 {
  34     public static synchronized MessageArea Instance ()
  35     {
  36         if (saInstance == null)
  37             saInstance = new MessageArea ();
  38         return saInstance;
  39     }
  40
  41
  42
  43
  44     /** Create a new message area.  This method is private because the class is
  45         a singleton and may therefore not be instantiated from the outside.
  46     */
  47     private MessageArea ()
  48     {
  49         maText = new JTextArea();
  50         maText.setBackground (new Color (255,250,240));
  51         maText.setFont (new Font ("Helvetica", Font.PLAIN, 9));
  52         setViewportView (maText);
  53         setVerticalScrollBarPolicy (JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
  54         setHorizontalScrollBarPolicy (JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
  55
  56         printMessage (
  57             "class path is " + System.getProperty ("java.class.path") + "\n");
  58     }
  59
  60
  61
  62
  63     /** Show the given string at the end of the message area and scroll to make
  64         it visible.  Indent the string as requested.
  65     */
  66     private static synchronized void print (int nIndentation, String aMessage)
  67     {
  68         while (nIndentation-- > 0) {
  69             aMessage = " " + aMessage;
  70         }
  71         Instance().printMessage(aMessage);
  72     }
  73
  74
  75
  76
  77     /** Show the given string at the end of the message area and scroll to make
  78         it visible.
  79     */
  80     public static void println (String aMessage)
  81     {
  82         println (0, aMessage);
  83     }
  84
  85
  86
  87
  88     /** Show the given string at the end of the message area and scroll to make
  89         it visible.
  90     */
  91     private static void println (int nIndentation, String aMessage)
  92     {
  93         print (nIndentation, aMessage+"\n");
  94     }
  95
  96
  97
  98
  99     @Override
 100     public void paintComponent (Graphics g)
 101     {
 102         synchronized (g)
 103         {
 104             JScrollBar sb = getVerticalScrollBar();
 105             if (sb != null)
 106             {
 107                 int nScrollBarValue = sb.getMaximum() - sb.getVisibleAmount() - 1;
 108                 sb.setValue (nScrollBarValue);
 109             }
 110             super.paintComponent (g);
 111         }
 112     }
 113
 114
 115
 116
 117     /** Append the given string to the end of the text and scroll so that it
 118         becomes visible.  This is an internal method.  Use one of the static
 119         and public ones.
 120     */
 121     private synchronized void printMessage (String aMessage)
 122     {
 123         maText.append (aMessage);
 124     }
 125
 126
 127
 128
 129     private static MessageArea saInstance = null;
 130     private final JTextArea maText;
 131 }