/**************************************************************
*
* 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
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*************************************************************/
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JEditorPane;
import javax.swing.JButton;
import java.net.URL;
import javax.swing.event.HyperlinkListener;
import javax.swing.event.HyperlinkEvent;
import java.net.MalformedURLException;
import java.io.IOException;
import java.io.File;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.GridBagLayout;
import java.awt.GridBagConstraints;
import java.awt.event.ActionListener;
import java.util.LinkedList;
class HelpWindow
implements ActionListener
{
public static synchronized HelpWindow Instance ()
{
if (maInstance == null)
maInstance = new HelpWindow();
return maInstance;
}
public void loadFile (String sFilename)
{
File aFile = new File (sFilename);
try
{
loadURL (aFile.toURL());
}
catch (MalformedURLException e)
{
e.printStackTrace (System.err);
}
}
public void loadURL (String sURL)
{
try
{
loadURL (new URL (sURL));
}
catch (MalformedURLException e)
{
e.printStackTrace (System.err);
}
}
public void loadURL (URL aURL)
{
maHistory.addLast (aURL);
selectHistoryPage (maHistory.size()-1);
maFrame.toFront ();
}
private HelpWindow ()
{
try
{
maCurrentHistoryEntry = -1;
maHistory = new LinkedList();
maFrame = new JFrame ();
maFrame.addWindowListener (new WindowAdapter ()
{
public void windowClosing (WindowEvent e)
{
maInstance = null;
}
});
maContent = createContentWidget();
maFrame.getContentPane().setLayout (new GridBagLayout());
GridBagConstraints aConstraints = new GridBagConstraints ();
aConstraints.gridx = 0;
aConstraints.gridy = 0;
aConstraints.gridwidth = 3;
aConstraints.weightx = 1;
aConstraints.weighty = 1;
aConstraints.fill = GridBagConstraints.BOTH;
maFrame.getContentPane().add (new JScrollPane (maContent), aConstraints);
aConstraints = new GridBagConstraints();
aConstraints.gridx = 0;
aConstraints.gridy = 1;
maPrevButton = new JButton ("Prev");
maFrame.getContentPane().add (maPrevButton, aConstraints);
maPrevButton.addActionListener (this);
aConstraints = new GridBagConstraints();
aConstraints.gridx = 1;
aConstraints.gridy = 1;
maNextButton = new JButton ("Next");
maFrame.getContentPane().add (maNextButton, aConstraints);
maNextButton.addActionListener (this);
aConstraints = new GridBagConstraints();
aConstraints.gridx = 2;
aConstraints.gridy = 1;
aConstraints.anchor = GridBagConstraints.EAST;
JButton aButton = new JButton ("Close");
maFrame.getContentPane().add (aButton, aConstraints);
aButton.addActionListener (this);
maFrame.setSize (600,400);
maFrame.setVisible (true);
}
catch (Exception e)
{}
}
public void actionPerformed (java.awt.event.ActionEvent e)
{
if (e.getActionCommand().equals("Prev"))
{
selectHistoryPage (maCurrentHistoryEntry - 1);
}
else if (e.getActionCommand().equals("Next"))
{
selectHistoryPage (maCurrentHistoryEntry + 1);
}
else if (e.getActionCommand().equals("Close"))
{
maFrame.dispose ();
maInstance = null;
}
}
private JEditorPane createContentWidget ()
{
JEditorPane aContent = new JEditorPane ();
aContent.setEditable (false);
aContent.addHyperlinkListener (new HyperlinkListener()
{
public void hyperlinkUpdate (HyperlinkEvent e)
{
if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED)
HelpWindow.Instance().loadURL (e.getURL());
}
});
return aContent;
}
private void selectHistoryPage (int i)
{
if (i < 0)
i = 0;
else if (i >= maHistory.size()-1)
i = maHistory.size()-1;
if (i != maCurrentHistoryEntry)
{
URL aURL = (URL)maHistory.get (i);
try
{
maContent.setPage (aURL);
}
catch (java.io.IOException ex)
{
ex.printStackTrace(System.err);
}
maCurrentHistoryEntry = i;
}
maPrevButton.setEnabled (maCurrentHistoryEntry > 0);
maNextButton.setEnabled (maCurrentHistoryEntry < maHistory.size()-1);
}
private static HelpWindow maInstance = null;
private JFrame maFrame;
private JEditorPane maContent;
private LinkedList maHistory;
private int maCurrentHistoryEntry;
private JButton maPrevButton;
private JButton maNextButton;
}