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/* NavigationFilterDemo.java -- An example for the NavigationFilter class.
Copyright (C) 2006 Free Software Foundation, Inc.
This file is part of GNU Classpath examples.
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Classpath 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.
*/
package gnu.classpath.examples.swing;
import java.awt.BorderLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
import javax.swing.text.BadLocationException;
import javax.swing.text.JTextComponent;
import javax.swing.text.NavigationFilter;
import javax.swing.text.Position;
import javax.swing.text.Utilities;
/**
* A demonstration of the <code>javax.swing.text.NavigationFilter</code> class.
*
* <p>It shows a NavigationFilter which lets you walk word-wise
* through a text.</p>
*
* @author Robert Schuster
*/
public class NavigationFilterDemo
extends JPanel
implements ActionListener
{
JTextArea textArea;
/**
* Creates a new demo instance.
*/
public NavigationFilterDemo()
{
createContent();
// initFrameContent() is only called (from main) when running this app
// standalone
}
/**
* When the demo is run independently, the frame is displayed, so we should
* initialise the content panel (including the demo content and a close
* button). But when the demo is run as part of the Swing activity board,
* only the demo content panel is used, the frame itself is never displayed,
* so we can avoid this step.
*/
void initFrameContent()
{
JPanel closePanel = new JPanel();
JButton closeButton = new JButton("Close");
closeButton.setActionCommand("CLOSE");
closeButton.addActionListener(this);
closePanel.add(closeButton);
add(closePanel, BorderLayout.SOUTH);
}
private void createContent()
{
setLayout(new BorderLayout());
add(textArea = new JTextArea(10, 20));
textArea.setWrapStyleWord(true);
textArea.setLineWrap(true);
textArea.setNavigationFilter(new WordFilter());
textArea.setText("GNU Classpath, Essential Libraries for Java, " +
"is a GNU project to create free core class " +
"libraries for use with virtual machines and " +
"compilers for the java programming language.");
}
public void actionPerformed(ActionEvent e)
{
if (e.getActionCommand().equals("CLOSE"))
System.exit(0);
}
public static void main(String[] args)
{
SwingUtilities.invokeLater
(new Runnable()
{
public void run()
{
NavigationFilterDemo app = new NavigationFilterDemo();
app.initFrameContent();
JFrame frame = new JFrame("NavigationFilterDemo");
frame.getContentPane().add(app);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
});
}
/**
* Returns a DemoFactory that creates a NavigationFilterDemo.
*
* @return a DemoFactory that creates a NavigationFilterDemo
*/
public static DemoFactory createDemoFactory()
{
return new DemoFactory()
{
public JComponent createDemo()
{
return new NavigationFilterDemo();
}
};
}
class WordFilter extends NavigationFilter
{
public int getNextVisualPositionFrom(JTextComponent text,
int pos,
Position.Bias bias,
int direction,
Position.Bias[] biasRet)
throws BadLocationException
{
Point pt;
int newpos = pos;
switch (direction)
{
case SwingConstants.NORTH:
// Find out where the caret want to be positioned ideally.
pt = text.getCaret().getMagicCaretPosition();
// Calculate its position above.
newpos = Utilities.getPositionAbove(text, pos, (pt != null) ? pt.x : 0);
// If we have a valid position, then calculate the next word start
// from there.
if (newpos != -1)
return Utilities.getWordStart(text, newpos);
else
return pos;
case SwingConstants.SOUTH:
// Find out where the caret want to be positioned ideally.
pt = text.getCaret().getMagicCaretPosition();
// Calculate its position below.
newpos = Utilities.getPositionBelow(text, pos, (pt != null) ? pt.x : 0);
// If we have a valid position, then calculate the next word start
// from there.
if (newpos != -1)
return Utilities.getWordStart(text, newpos);
else
return pos;
case SwingConstants.WEST:
// Calculate the next word start.
newpos = Utilities.getWordStart(text, newpos);
// If that means that the caret will not move, return
// the start of the previous word.
if (newpos != pos)
return newpos;
else
return Utilities.getPreviousWord(text, newpos);
case SwingConstants.EAST:
return Utilities.getNextWord(text, newpos);
default:
// Do whatever the super implementation did.
return super.getNextVisualPositionFrom(text, pos, bias,
direction, biasRet);
}
}
}
}
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