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/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
import java.awt.Font;
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JScrollBar;
/** A message area displays text in a scrollable text widget. It is a
singleton. Other objects can access it directly to display messages.
*/
public class MessageArea
extends JScrollPane
{
public static synchronized MessageArea Instance ()
{
if (saInstance == null)
saInstance = new MessageArea ();
return saInstance;
}
/** Create a new message area. This method is private because the class is
a singleton and may therefore not be instantiated from the outside.
*/
private MessageArea ()
{
maText = new JTextArea();
maText.setBackground (new Color (255,250,240));
maText.setFont (new Font ("Helvetica", Font.PLAIN, 9));
setViewportView (maText);
setVerticalScrollBarPolicy (JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
setHorizontalScrollBarPolicy (JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
printMessage (
"class path is " + System.getProperty ("java.class.path") + "\n");
}
/** Show the given string at the end of the message area and scroll to make
it visible. Indent the string as requested.
*/
private static synchronized void print (int nIndentation, String aMessage)
{
while (nIndentation-- > 0) {
aMessage = " " + aMessage;
}
Instance().printMessage(aMessage);
}
/** Show the given string at the end of the message area and scroll to make
it visible.
*/
public static void println (String aMessage)
{
println (0, aMessage);
}
/** Show the given string at the end of the message area and scroll to make
it visible.
*/
private static void println (int nIndentation, String aMessage)
{
print (nIndentation, aMessage+"\n");
}
@Override
public void paintComponent (Graphics g)
{
synchronized (g)
{
JScrollBar sb = getVerticalScrollBar();
if (sb != null)
{
int nScrollBarValue = sb.getMaximum() - sb.getVisibleAmount() - 1;
sb.setValue (nScrollBarValue);
}
super.paintComponent (g);
}
}
/** Append the given string to the end of the text and scroll so that it
becomes visible. This is an internal method. Use one of the static
and public ones.
*/
private synchronized void printMessage (String aMessage)
{
maText.append (aMessage);
}
private static MessageArea saInstance = null;
private final JTextArea maText;
}
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