package net.sourceforge.squirrel_sql.fw.gui;
/*
* Copyright (C) 2001-2003 Colin Bell
* colbell@users.sourceforge.net
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import javax.swing.ImageIcon;
import javax.swing.JComponent;
import javax.swing.JFileChooser;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import net.sourceforge.squirrel_sql.fw.util.StringManager;
import net.sourceforge.squirrel_sql.fw.util.StringManagerFactory;
import net.sourceforge.squirrel_sql.fw.util.Utilities;
/**
* This is a decorator class that can be used in a <TT>JFileChooser</TT>
* to preview the contents of a text or image file. If the file name
* has a suffix of jpg, jpeg, gif or png this class will attempt to render
* it as an image, else it will render it as text.
*
* @author <A HREF="mailto:colbell@users.sourceforge.net">Colin Bell</A>
*/
public class ChooserPreviewer extends JComponent
{
/** Internationalized strings for this class. */
private static final StringManager s_stringMgr =
StringManagerFactory.getStringManager(ChooserPreviewer.class);
/** Default number of bytes to read from file for preview. */
private int DFT_BYTES_TO_READ = 2048;
/**
* Empty panel. Used when cannot display anything in the
* preview panel.
*/
private final JPanel _emptyPnl = new JPanel();
/** Text area to display the contents of a text file in. */
private final JTextArea _textComponent = new JTextArea();
/** Label to display the contents of an image file in. */
private final JLabel _imageComponent = new JLabel();
/** Component currently being displayed in the preview area. */
private Component _currentComponent;
/** Scrollpane for <TT>_currentComponent</TT>. */
private JScrollPane _currentComponentSp;
/** <TT>JFileChooser</TT> that this accessory belongs to. */
private JFileChooser _chooser;
/**
* Listener listening to <TT>JFileChooser</TT> for a change
* in the selected file.
*/
private ChooserListener _propChangeListener;
/**
* Default ctor.
*/
public ChooserPreviewer()
{
super();
createUserInterface();
}
/**
* This accessory is being added to a chooser. Add a listener
* to the chooser for when the selected file changes.
*/
public void addNotify()
{
super.addNotify();
cleanup();
Component parent = getParent();
while (parent != null)
{
if (parent instanceof JFileChooser)
{
_chooser = (JFileChooser)parent;
break;
}
parent = parent.getParent();
}
if (_chooser != null)
{
_propChangeListener = new ChooserListener();
_chooser.addPropertyChangeListener(_propChangeListener);
}
}
/**
* This accessory is being removed from a chooser. Remove
* the listener from the chooser.
*/
public void removeNotify()
{
super.removeNotify();
cleanup();
}
/**
* Remove listener from the chooser.
*/
protected void cleanup()
{
if (_chooser != null && _propChangeListener != null)
{
_chooser.removePropertyChangeListener(_propChangeListener);
}
_propChangeListener = null;
_chooser = null;
}
/**
* The file selected in the <TT>FileChooser</TT> has changed so display
* its contents in this previewer.
*/
protected void fileChanged()
{
Component componentToUse = _emptyPnl;
File file = _chooser.getSelectedFile();
if (file != null && file.isFile() && file.canRead())
{
String suffix = Utilities.getFileNameSuffix(file.getPath()).toLowerCase();
if (suffix.equals("gif") || suffix.equals("jpg")
|| suffix.equals("jpeg") || suffix.equals("png"))
{
componentToUse = readImageFile(file);
}
else
{
componentToUse = readTextFile(file);
}
}
if (componentToUse != _currentComponent)
{
_currentComponentSp.setViewportView(componentToUse);
_currentComponent = componentToUse;
}
}
/**
* Read the image from the passed file and return it within
* a component.
*
* @param file The file to be read.
*
* @return The image component.
*/
protected Component readImageFile(File file)
{
final ImageIcon icon = new ImageIcon(file.getPath());
_imageComponent.setIcon(icon);
return _imageComponent;
}
/**
* Read the first portion of the passed file
* and place them in the text component. If cannot
* read it then clear the text component.
*
* @param file The file to be read.
*
* @return The text component
*/
protected Component readTextFile(File file)
{
StringBuffer buf = new StringBuffer(DFT_BYTES_TO_READ);
if (file != null && file.isFile() && file.canRead())
{
try
{
FileReader rdr = new FileReader(file);
try
{
char[] data = new char[DFT_BYTES_TO_READ];
int count = rdr.read(data, 0, data.length);
if (count != -1)
{
buf.append(data, 0, count);
}
}
finally
{
rdr.close();
}
}
catch (IOException ex)
{
buf = new StringBuffer(s_stringMgr.getString("ChooserPreviewer.error", ex.toString()));
}
}
_textComponent.setText(buf.toString());
_textComponent.setCaretPosition(0);
return _textComponent;
}
/**
* Create the User Interface.
*/
private void createUserInterface()
{
_textComponent.setEditable(false);
setLayout(new BorderLayout());
_currentComponentSp = new JScrollPane(_textComponent);
add(_currentComponentSp, BorderLayout.CENTER);
setPreferredSize(new Dimension(250, 0));
}
/**
* Listener to the FileChooser that will preview the seleted file
* as it changes in the chooser.
*/
private class ChooserListener implements PropertyChangeListener
{
public void propertyChange(PropertyChangeEvent evt)
{
if (evt.getPropertyName().equals(JFileChooser.SELECTED_FILE_CHANGED_PROPERTY))
{
ChooserPreviewer.this.fileChanged();
}
}
}
}