Ed.java

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.*;

public class Ed extends JFrame {
    protected static String[] fontNames;
    protected int selectedFontIndex;
    protected int fontSize = 14;
    private JTextArea editbox;
    private JMenuItem[] mnuFonts;
    private JCheckBoxMenuItem mnuBold, mnuItalic;
    private JFileChooser chooser;
    private File file;
    private boolean dirty = false;

public Ed() {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                initGUI();
            }
        });
    }
   
    private void initGUI() {
        // create window for editor
        JFrame fra = new JFrame("Ed - Text Editor");
        fra.setSize(500, 500);

// add document area to editor
        editbox = new JTextArea();
        JScrollPane sp = new JScrollPane(editbox);
        Container c = fra.getContentPane();
        c.setLayout(new BorderLayout());
        c.add(sp, BorderLayout.CENTER);

// get all fonts on system
        fontNames = GraphicsEnvironment
            .getLocalGraphicsEnvironment()
            .getAvailableFontFamilyNames();

// add menu bar to editor
        fra.setJMenuBar(createMenuBar());

chooser = new JFileChooser();
        try {
            chooser.setCurrentDirectory((new File(".")).getCanonicalFile());
        } catch (IOException e2) {}

selectedFontIndex = 0;
        refresh();
        startNewDoc();

fra.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                if (!shouldSave()) return;
                System.exit(0);
            }
        });
        fra.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        fra.setVisible(true);
    }

private JMenuBar createMenuBar() {
        // needs to be final for event handlers
        final JMenuBar menuBar = new JMenuBar();

// create File menu
        JMenu mnuFile = new JMenu("File");
        mnuFile.setMnemonic('f');

// create File New menu item
        JMenuItem mnuItem = new JMenuItem(new AbstractAction("New") {
            public void actionPerformed(ActionEvent e) {
                if (!shouldSave()) return;
                startNewDoc();
            }
        });
        mnuItem.setMnemonic('n');
        mnuItem.setAccelerator(KeyStroke.getKeyStroke(
            KeyEvent.VK_N, InputEvent.CTRL_MASK));
        mnuFile.add(mnuItem);

// create File Open... menu item
        mnuItem = new JMenuItem(new AbstractAction("Open...") {
            public void actionPerformed(ActionEvent e) {
                if (!shouldSave()) return;
                openDoc();
            }
        });
        mnuItem.setMnemonic('o');
        mnuItem.setAccelerator(KeyStroke.getKeyStroke(
            KeyEvent.VK_O, InputEvent.CTRL_MASK));
        mnuFile.add(mnuItem);

// create File Save menu item
        mnuItem = new JMenuItem(new AbstractAction("Save") {
            public void actionPerformed(ActionEvent e) {
                if (!dirty) return;
                saveFile(false);
            }
        });
        mnuItem.setMnemonic('s');
        mnuItem.setAccelerator(KeyStroke.getKeyStroke(
            KeyEvent.VK_S, InputEvent.CTRL_MASK));
        mnuFile.add(mnuItem);

// create File Save As... menu item
        mnuItem = new JMenuItem(new AbstractAction("Save As...") {
            public void actionPerformed(ActionEvent e) {
                saveFile(true);
            }
        });
        mnuItem.setMnemonic('a');
        mnuFile.add(mnuItem);

mnuFile.addSeparator();

// create File Exit menu item
        mnuItem = new JMenuItem(new AbstractAction("Exit") {
            public void actionPerformed(ActionEvent e) {
                if (!shouldSave()) return;
                System.exit(0);
            }
        });
        mnuItem.setMnemonic('x');
        mnuFile.add(mnuItem);
        menuBar.add(mnuFile);

ActionListener fontChangeListener = new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                refresh();
            }
        };

JMenu mnuFont = new JMenu("Font");
        mnuFont.setMnemonic('o');

mnuBold = new JCheckBoxMenuItem("Bold");
        mnuBold.setMnemonic('b');
        mnuBold.setSelected(false);
        mnuBold.addActionListener(fontChangeListener);
        mnuFont.add(mnuBold);

mnuItalic = new JCheckBoxMenuItem("Italic");
        mnuItalic.setMnemonic('i');
        mnuItalic.setSelected(false);
        mnuItalic.addActionListener(fontChangeListener);
        mnuFont.add(mnuItalic);

mnuFont.addSeparator();

FontMenu fmenu = new FontMenu("Fonts");
        mnuFont.add(fmenu);

menuBar.add(mnuFont);
        return menuBar;
    }

private String getDocName() {
        return file==null ? "Untitled" : file.getName();
    }

protected void startNewDoc() {
        editbox.setText("");
        file = null;
        setTitle("Ed - [" + getDocName() + "]");
        dirty = false;
        editbox.getDocument().addDocumentListener(new DocListener());
    }

protected void openDoc() {
        if (chooser.showOpenDialog(Ed.this) !=
            JFileChooser.APPROVE_OPTION)
            return;
        File f = chooser.getSelectedFile();
        if (f == null || !f.isFile()) return;
        file = f;
        try {
            FileReader in = new FileReader(file);
            editbox.read(in, null);
            in.close();
            setTitle("Ed" + " [" + getDocName() + "]");
        }
        catch (IOException e2) {
            error(e2, "Error reading file "+file);
        }
        dirty = false;
        editbox.getDocument().addDocumentListener(new DocListener());
    }

protected boolean saveFile(boolean saveAs) {
        if (saveAs || file == null) {
            if (chooser.showSaveDialog(Ed.this) !=
                JFileChooser.APPROVE_OPTION)
                return false;
            File f = chooser.getSelectedFile();
            if (f == null) return false;
            file = f;
            setTitle("Ed" + " [" + getDocName() + "]");
        }

try {
            FileWriter out = new FileWriter(file);
            editbox.write(out);
            out.close();
        }
        catch (IOException e2) {
            error(e2, "Error saving file "+file);
            return false;
        }
        dirty = false;
        return true;
    }

protected boolean shouldSave() {
        if (!dirty) return true;
        int ans = JOptionPane.showConfirmDialog(this,
            "Save changes to " + getDocName() + "?",
            "Ed", JOptionPane.YES_NO_CANCEL_OPTION,
            JOptionPane.INFORMATION_MESSAGE);
        if (ans == JOptionPane.YES_OPTION) {
            if (!saveFile(false)) return false;
            else return true;
        }
        return ans==JOptionPane.NO_OPTION;
    }

protected void refresh() {
        int fontStyle = Font.PLAIN;
        if (mnuBold.isSelected()) fontStyle |= Font.BOLD;
        if (mnuItalic.isSelected()) fontStyle |= Font.ITALIC;
        Font font = new Font(fontNames[selectedFontIndex], fontStyle, fontSize);
        editbox.setFont(font);
        editbox.repaint();
    }

public void error(Exception e, String message) {
        e.printStackTrace();
        JOptionPane.showMessageDialog(this, message, "Ed",
            JOptionPane.WARNING_MESSAGE);
    }

public static void main(String argv[]) {
        Ed app = new Ed();
    }
   
    // set inside Ed to get access to variable named: dirty
    class DocListener implements DocumentListener {
        public void insertUpdate(DocumentEvent e) { dirty = true; }
        public void removeUpdate(DocumentEvent e) { dirty = true; }
        public void changedUpdate(DocumentEvent e) { dirty = true; }
    }

class FontMenu extends JMenu {
        public FontMenu(String name) {
            super(name);
            JPanel p = new JPanel();
            p.setLayout(new BorderLayout());
            final JList fontlist = new JList(fontNames);
            fontlist.addMouseListener(new MouseAdapter() {
                public void mouseClicked(MouseEvent e) {
                    int ndx = fontlist.locationToIndex(e.getPoint());
                    selectedFontIndex = ndx;
                    refresh();
                }
            });
            JScrollPane scrollList = new JScrollPane(fontlist);
            p.add(scrollList, BorderLayout.CENTER);
            add(p);
        }
    }
}