java.util.Preferences

[jon80]

1. The .xml file is not saved with an .xml extension by default.
2. I would like to update the code so that the width and height of the frame are saved within the .xml saved by the user.
3. How can I validate my xml file against the schema? (http://java.sun.com/dtd/preferences.dtd)

:confused:

package homenetwork.bkr.training;

import java.awt.EventQueue;
import java.awt.event.*;
import java.io.*;
import java.util.prefs.*;
import javax.swing.*;

@SuppressWarnings("serial")
public class PreferencesFrame extends JFrame {
	
	public PreferencesFrame()
	{
		//get position, size and title from preferences
		Preferences root = Preferences.userRoot();
		final Preferences node = root.node("/com/horstmann/corejava");
		int left = node.getInt("left", 0);
		int top = node.getInt("top", 0);
		int width = node.getInt("width", DEFAULT_WIDTH);
		int height = node.getInt("height", DEFAULT_HEIGHT);
		setBounds(left, top, width, height);
		
		//if no title given, ask user
		String title = node.get("title", "");
		if (title.equals("")) title = JOptionPane.showInputDialog("Please supply a frame title:");
		if (title == null) title = "";
		setTitle(title);
		
		//set up file chooser that shows XML files
		final JFileChooser chooser = new JFileChooser();
		chooser.setCurrentDirectory(new File("."));
		
		//accept all files ending with .xml
		chooser.setFileFilter(new javax.swing.filechooser.FileFilter()
		{
			public boolean accept (File f)
			{
				return f.getName().toLowerCase().endsWith(".xml") || f.isDirectory();
			}
			public String getDescription()
			{
				return "XML files";
			}
		});
		
		//set up menus
		JMenuBar menuBar = new JMenuBar();
		setJMenuBar(menuBar);
		JMenu menu = new JMenu("File");
		menuBar.add(menu);
		
		[B]JMenuItem exportItem = new JMenuItem("Export preferences");[/B]
		menu.add(exportItem);
		exportItem.addActionListener(new ActionListener()

		{
			public void actionPerformed(ActionEvent event)
			{
				if (chooser.showSaveDialog(PreferencesFrame.this) == JFileChooser.APPROVE_OPTION)
				{
					try 
					{
						OutputStream out = new FileOutputStream(chooser.getSelectedFile());
						node.exportSubtree(out);
						out.close();
					}
					catch (Exception e)
					{
						e.printStackTrace();
					}
				}
			}
		});

		JMenuItem importItem = new JMenuItem("Import preferences");
		menu.add(importItem);
		importItem.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent event)
			{
				if (chooser.showOpenDialog(PreferencesFrame.this) == JFileChooser.APPROVE_OPTION)
					try
					{
						InputStream in = new FileInputStream(chooser.getSelectedFile());
						Preferences.importPreferences(in);
						in.close();
					}
					catch (Exception e)
					{
						e.printStackTrace();
					}
			}
		});
		
		JMenuItem exitItem = new JMenuItem("Exit");
		menu.add(exitItem);
		exitItem.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent event)
			{  //save settings before exiting

				[B]node.putInt("left", getX());
				node.putInt("top", getY());
				node.putInt("width", getWidth());
				node.putInt("height", getHeight());
				node.put("title", getTitle());
				System.exit(0);[/B]
			}
		});
	}

	public static final int DEFAULT_WIDTH = 300;
	public static final int DEFAULT_HEIGHT = 200;
	//TODO update the code so that the width and height of the frame
	//     are saved within the preferences file.
}