Java example source code file (Notepad.java)
The Notepad.java Java example source code
/*
* Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of Oracle nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* This source code is provided to illustrate the usage of a given feature
* or technique and has been deliberately simplified. Additional steps
* required for a production-quality application, such as security checks,
* input validation and proper error handling, might not be present in
* this sample code.
*/
import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.*;
import java.net.*;
import java.util.*;
import java.util.logging.*;
import javax.swing.*;
import javax.swing.undo.*;
import javax.swing.text.*;
import javax.swing.event.*;
import javax.swing.UIManager.LookAndFeelInfo;
/**
* Sample application using the simple text editor component that
* supports only one font.
*
* @author Timothy Prinzing
*/
@SuppressWarnings("serial")
class Notepad extends JPanel {
protected static Properties properties;
private static ResourceBundle resources;
private final static String EXIT_AFTER_PAINT = "-exit";
private static boolean exitAfterFirstPaint;
private static final String[] MENUBAR_KEYS = {"file", "edit", "debug"};
private static final String[] TOOLBAR_KEYS = {"new", "open", "save", "-", "cut", "copy", "paste"};
private static final String[] FILE_KEYS = {"new", "open", "save", "-", "exit"};
private static final String[] EDIT_KEYS = {"cut", "copy", "paste", "-", "undo", "redo"};
private static final String[] DEBUG_KEYS = {"dump", "showElementTree"};
static {
try {
properties = new Properties();
properties.load(Notepad.class.getResourceAsStream(
"resources/NotepadSystem.properties"));
resources = ResourceBundle.getBundle("resources.Notepad",
Locale.getDefault());
} catch (MissingResourceException | IOException e) {
System.err.println("resources/Notepad.properties "
+ "or resources/NotepadSystem.properties not found");
System.exit(1);
}
}
@Override
public void paintChildren(Graphics g) {
super.paintChildren(g);
if (exitAfterFirstPaint) {
System.exit(0);
}
}
@SuppressWarnings("OverridableMethodCallInConstructor")
Notepad() {
super(true);
// Trying to set Nimbus look and feel
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception ignored) {
}
setBorder(BorderFactory.createEtchedBorder());
setLayout(new BorderLayout());
// create the embedded JTextComponent
editor = createEditor();
// Add this as a listener for undoable edits.
editor.getDocument().addUndoableEditListener(undoHandler);
// install the command table
commands = new HashMap<Object, Action>();
Action[] actions = getActions();
for (Action a : actions) {
commands.put(a.getValue(Action.NAME), a);
}
JScrollPane scroller = new JScrollPane();
JViewport port = scroller.getViewport();
port.add(editor);
String vpFlag = getProperty("ViewportBackingStore");
if (vpFlag != null) {
Boolean bs = Boolean.valueOf(vpFlag);
port.setScrollMode(bs
? JViewport.BACKINGSTORE_SCROLL_MODE
: JViewport.BLIT_SCROLL_MODE);
}
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
panel.add("North", createToolbar());
panel.add("Center", scroller);
add("Center", panel);
add("South", createStatusbar());
}
public static void main(String[] args) throws Exception {
if (args.length > 0 && args[0].equals(EXIT_AFTER_PAINT)) {
exitAfterFirstPaint = true;
}
SwingUtilities.invokeAndWait(new Runnable() {
public void run() {
JFrame frame = new JFrame();
frame.setTitle(resources.getString("Title"));
frame.setBackground(Color.lightGray);
frame.getContentPane().setLayout(new BorderLayout());
Notepad notepad = new Notepad();
frame.getContentPane().add("Center", notepad);
frame.setJMenuBar(notepad.createMenubar());
frame.addWindowListener(new AppCloser());
frame.pack();
frame.setSize(500, 600);
frame.setVisible(true);
}
});
}
/**
* Fetch the list of actions supported by this
* editor. It is implemented to return the list
* of actions supported by the embedded JTextComponent
* augmented with the actions defined locally.
*/
public Action[] getActions() {
return TextAction.augmentList(editor.getActions(), defaultActions);
}
/**
* Create an editor to represent the given document.
*/
protected JTextComponent createEditor() {
JTextComponent c = new JTextArea();
c.setDragEnabled(true);
c.setFont(new Font("monospaced", Font.PLAIN, 12));
return c;
}
/**
* Fetch the editor contained in this panel
*/
protected JTextComponent getEditor() {
return editor;
}
/**
* To shutdown when run as an application. This is a
* fairly lame implementation. A more self-respecting
* implementation would at least check to see if a save
* was needed.
*/
protected static final class AppCloser extends WindowAdapter {
@Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
}
/**
* Find the hosting frame, for the file-chooser dialog.
*/
protected Frame getFrame() {
for (Container p = getParent(); p != null; p = p.getParent()) {
if (p instanceof Frame) {
return (Frame) p;
}
}
return null;
}
/**
* This is the hook through which all menu items are
* created.
*/
protected JMenuItem createMenuItem(String cmd) {
JMenuItem mi = new JMenuItem(getResourceString(cmd + labelSuffix));
URL url = getResource(cmd + imageSuffix);
if (url != null) {
mi.setHorizontalTextPosition(JButton.RIGHT);
mi.setIcon(new ImageIcon(url));
}
String astr = getProperty(cmd + actionSuffix);
if (astr == null) {
astr = cmd;
}
mi.setActionCommand(astr);
Action a = getAction(astr);
if (a != null) {
mi.addActionListener(a);
a.addPropertyChangeListener(createActionChangeListener(mi));
mi.setEnabled(a.isEnabled());
} else {
mi.setEnabled(false);
}
return mi;
}
protected Action getAction(String cmd) {
return commands.get(cmd);
}
protected String getProperty(String key) {
return properties.getProperty(key);
}
protected String getResourceString(String nm) {
String str;
try {
str = resources.getString(nm);
} catch (MissingResourceException mre) {
str = null;
}
return str;
}
protected URL getResource(String key) {
String name = getResourceString(key);
if (name != null) {
return this.getClass().getResource(name);
}
return null;
}
/**
* Create a status bar
*/
protected Component createStatusbar() {
// need to do something reasonable here
status = new StatusBar();
return status;
}
/**
* Resets the undo manager.
*/
protected void resetUndoManager() {
undo.discardAllEdits();
undoAction.update();
redoAction.update();
}
/**
* Create the toolbar. By default this reads the
* resource file for the definition of the toolbar.
*/
private Component createToolbar() {
toolbar = new JToolBar();
for (String toolKey: getToolBarKeys()) {
if (toolKey.equals("-")) {
toolbar.add(Box.createHorizontalStrut(5));
} else {
toolbar.add(createTool(toolKey));
}
}
toolbar.add(Box.createHorizontalGlue());
return toolbar;
}
/**
* Hook through which every toolbar item is created.
*/
protected Component createTool(String key) {
return createToolbarButton(key);
}
/**
* Create a button to go inside of the toolbar. By default this
* will load an image resource. The image filename is relative to
* the classpath (including the '.' directory if its a part of the
* classpath), and may either be in a JAR file or a separate file.
*
* @param key The key in the resource file to serve as the basis
* of lookups.
*/
protected JButton createToolbarButton(String key) {
URL url = getResource(key + imageSuffix);
JButton b = new JButton(new ImageIcon(url)) {
@Override
public float getAlignmentY() {
return 0.5f;
}
};
b.setRequestFocusEnabled(false);
b.setMargin(new Insets(1, 1, 1, 1));
String astr = getProperty(key + actionSuffix);
if (astr == null) {
astr = key;
}
Action a = getAction(astr);
if (a != null) {
b.setActionCommand(astr);
b.addActionListener(a);
} else {
b.setEnabled(false);
}
String tip = getResourceString(key + tipSuffix);
if (tip != null) {
b.setToolTipText(tip);
}
return b;
}
/**
* Create the menubar for the app. By default this pulls the
* definition of the menu from the associated resource file.
*/
protected JMenuBar createMenubar() {
JMenuBar mb = new JMenuBar();
for(String menuKey: getMenuBarKeys()){
JMenu m = createMenu(menuKey);
if (m != null) {
mb.add(m);
}
}
return mb;
}
/**
* Create a menu for the app. By default this pulls the
* definition of the menu from the associated resource file.
*/
protected JMenu createMenu(String key) {
JMenu menu = new JMenu(getResourceString(key + labelSuffix));
for (String itemKey: getItemKeys(key)) {
if (itemKey.equals("-")) {
menu.addSeparator();
} else {
JMenuItem mi = createMenuItem(itemKey);
menu.add(mi);
}
}
return menu;
}
/**
* Get keys for menus
*/
protected String[] getItemKeys(String key) {
switch (key) {
case "file":
return FILE_KEYS;
case "edit":
return EDIT_KEYS;
case "debug":
return DEBUG_KEYS;
default:
return null;
}
}
protected String[] getMenuBarKeys() {
return MENUBAR_KEYS;
}
protected String[] getToolBarKeys() {
return TOOLBAR_KEYS;
}
// Yarked from JMenu, ideally this would be public.
protected PropertyChangeListener createActionChangeListener(JMenuItem b) {
return new ActionChangedListener(b);
}
// Yarked from JMenu, ideally this would be public.
private class ActionChangedListener implements PropertyChangeListener {
JMenuItem menuItem;
ActionChangedListener(JMenuItem mi) {
super();
this.menuItem = mi;
}
public void propertyChange(PropertyChangeEvent e) {
String propertyName = e.getPropertyName();
if (e.getPropertyName().equals(Action.NAME)) {
String text = (String) e.getNewValue();
menuItem.setText(text);
} else if (propertyName.equals("enabled")) {
Boolean enabledState = (Boolean) e.getNewValue();
menuItem.setEnabled(enabledState.booleanValue());
}
}
}
private JTextComponent editor;
private Map<Object, Action> commands;
private JToolBar toolbar;
private JComponent status;
private JFrame elementTreeFrame;
protected ElementTreePanel elementTreePanel;
/**
* Listener for the edits on the current document.
*/
protected UndoableEditListener undoHandler = new UndoHandler();
/** UndoManager that we add edits to. */
protected UndoManager undo = new UndoManager();
/**
* Suffix applied to the key used in resource file
* lookups for an image.
*/
public static final String imageSuffix = "Image";
/**
* Suffix applied to the key used in resource file
* lookups for a label.
*/
public static final String labelSuffix = "Label";
/**
* Suffix applied to the key used in resource file
* lookups for an action.
*/
public static final String actionSuffix = "Action";
/**
* Suffix applied to the key used in resource file
* lookups for tooltip text.
*/
public static final String tipSuffix = "Tooltip";
public static final String openAction = "open";
public static final String newAction = "new";
public static final String saveAction = "save";
public static final String exitAction = "exit";
public static final String showElementTreeAction = "showElementTree";
class UndoHandler implements UndoableEditListener {
/**
* Messaged when the Document has created an edit, the edit is
* added to <code>undo, an instance of UndoManager.
*/
public void undoableEditHappened(UndoableEditEvent e) {
undo.addEdit(e.getEdit());
undoAction.update();
redoAction.update();
}
}
/**
* FIXME - I'm not very useful yet
*/
class StatusBar extends JComponent {
public StatusBar() {
super();
setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
}
@Override
public void paint(Graphics g) {
super.paint(g);
}
}
// --- action implementations -----------------------------------
private UndoAction undoAction = new UndoAction();
private RedoAction redoAction = new RedoAction();
/**
* Actions defined by the Notepad class
*/
private Action[] defaultActions = {
new NewAction(),
new OpenAction(),
new SaveAction(),
new ExitAction(),
new ShowElementTreeAction(),
undoAction,
redoAction
};
class UndoAction extends AbstractAction {
public UndoAction() {
super("Undo");
setEnabled(false);
}
public void actionPerformed(ActionEvent e) {
try {
undo.undo();
} catch (CannotUndoException ex) {
Logger.getLogger(UndoAction.class.getName()).log(Level.SEVERE,
"Unable to undo", ex);
}
update();
redoAction.update();
}
protected void update() {
if (undo.canUndo()) {
setEnabled(true);
putValue(Action.NAME, undo.getUndoPresentationName());
} else {
setEnabled(false);
putValue(Action.NAME, "Undo");
}
}
}
class RedoAction extends AbstractAction {
public RedoAction() {
super("Redo");
setEnabled(false);
}
public void actionPerformed(ActionEvent e) {
try {
undo.redo();
} catch (CannotRedoException ex) {
Logger.getLogger(RedoAction.class.getName()).log(Level.SEVERE,
"Unable to redo", ex);
}
update();
undoAction.update();
}
protected void update() {
if (undo.canRedo()) {
setEnabled(true);
putValue(Action.NAME, undo.getRedoPresentationName());
} else {
setEnabled(false);
putValue(Action.NAME, "Redo");
}
}
}
class OpenAction extends NewAction {
OpenAction() {
super(openAction);
}
@Override
public void actionPerformed(ActionEvent e) {
Frame frame = getFrame();
JFileChooser chooser = new JFileChooser();
int ret = chooser.showOpenDialog(frame);
if (ret != JFileChooser.APPROVE_OPTION) {
return;
}
File f = chooser.getSelectedFile();
if (f.isFile() && f.canRead()) {
Document oldDoc = getEditor().getDocument();
if (oldDoc != null) {
oldDoc.removeUndoableEditListener(undoHandler);
}
if (elementTreePanel != null) {
elementTreePanel.setEditor(null);
}
getEditor().setDocument(new PlainDocument());
frame.setTitle(f.getName());
Thread loader = new FileLoader(f, editor.getDocument());
loader.start();
} else {
JOptionPane.showMessageDialog(getFrame(),
"Could not open file: " + f,
"Error opening file",
JOptionPane.ERROR_MESSAGE);
}
}
}
class SaveAction extends AbstractAction {
SaveAction() {
super(saveAction);
}
public void actionPerformed(ActionEvent e) {
Frame frame = getFrame();
JFileChooser chooser = new JFileChooser();
int ret = chooser.showSaveDialog(frame);
if (ret != JFileChooser.APPROVE_OPTION) {
return;
}
File f = chooser.getSelectedFile();
frame.setTitle(f.getName());
Thread saver = new FileSaver(f, editor.getDocument());
saver.start();
}
}
class NewAction extends AbstractAction {
NewAction() {
super(newAction);
}
NewAction(String nm) {
super(nm);
}
public void actionPerformed(ActionEvent e) {
Document oldDoc = getEditor().getDocument();
if (oldDoc != null) {
oldDoc.removeUndoableEditListener(undoHandler);
}
getEditor().setDocument(new PlainDocument());
getEditor().getDocument().addUndoableEditListener(undoHandler);
resetUndoManager();
getFrame().setTitle(resources.getString("Title"));
revalidate();
}
}
/**
* Really lame implementation of an exit command
*/
class ExitAction extends AbstractAction {
ExitAction() {
super(exitAction);
}
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
/**
* Action that brings up a JFrame with a JTree showing the structure
* of the document.
*/
class ShowElementTreeAction extends AbstractAction {
ShowElementTreeAction() {
super(showElementTreeAction);
}
public void actionPerformed(ActionEvent e) {
if (elementTreeFrame == null) {
// Create a frame containing an instance of
// ElementTreePanel.
try {
String title = resources.getString("ElementTreeFrameTitle");
elementTreeFrame = new JFrame(title);
} catch (MissingResourceException mre) {
elementTreeFrame = new JFrame();
}
elementTreeFrame.addWindowListener(new WindowAdapter() {
@Override
public void windowClosing(WindowEvent weeee) {
elementTreeFrame.setVisible(false);
}
});
Container fContentPane = elementTreeFrame.getContentPane();
fContentPane.setLayout(new BorderLayout());
elementTreePanel = new ElementTreePanel(getEditor());
fContentPane.add(elementTreePanel);
elementTreeFrame.pack();
}
elementTreeFrame.setVisible(true);
}
}
/**
* Thread to load a file into the text storage model
*/
class FileLoader extends Thread {
FileLoader(File f, Document doc) {
setPriority(4);
this.f = f;
this.doc = doc;
}
@Override
public void run() {
try {
// initialize the statusbar
status.removeAll();
JProgressBar progress = new JProgressBar();
progress.setMinimum(0);
progress.setMaximum((int) f.length());
status.add(progress);
status.revalidate();
// try to start reading
Reader in = new FileReader(f);
char[] buff = new char[4096];
int nch;
while ((nch = in.read(buff, 0, buff.length)) != -1) {
doc.insertString(doc.getLength(), new String(buff, 0, nch),
null);
progress.setValue(progress.getValue() + nch);
}
} catch (IOException e) {
final String msg = e.getMessage();
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JOptionPane.showMessageDialog(getFrame(),
"Could not open file: " + msg,
"Error opening file",
JOptionPane.ERROR_MESSAGE);
}
});
} catch (BadLocationException e) {
System.err.println(e.getMessage());
}
doc.addUndoableEditListener(undoHandler);
// we are done... get rid of progressbar
status.removeAll();
status.revalidate();
resetUndoManager();
if (elementTreePanel != null) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
elementTreePanel.setEditor(getEditor());
}
});
}
}
Document doc;
File f;
}
/**
* Thread to save a document to file
*/
class FileSaver extends Thread {
Document doc;
File f;
FileSaver(File f, Document doc) {
setPriority(4);
this.f = f;
this.doc = doc;
}
@Override
@SuppressWarnings("SleepWhileHoldingLock")
public void run() {
try {
// initialize the statusbar
status.removeAll();
JProgressBar progress = new JProgressBar();
progress.setMinimum(0);
progress.setMaximum(doc.getLength());
status.add(progress);
status.revalidate();
// start writing
Writer out = new FileWriter(f);
Segment text = new Segment();
text.setPartialReturn(true);
int charsLeft = doc.getLength();
int offset = 0;
while (charsLeft > 0) {
doc.getText(offset, Math.min(4096, charsLeft), text);
out.write(text.array, text.offset, text.count);
charsLeft -= text.count;
offset += text.count;
progress.setValue(offset);
try {
Thread.sleep(10);
} catch (InterruptedException e) {
Logger.getLogger(FileSaver.class.getName()).log(
Level.SEVERE,
null, e);
}
}
out.flush();
out.close();
} catch (IOException e) {
final String msg = e.getMessage();
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JOptionPane.showMessageDialog(getFrame(),
"Could not save file: " + msg,
"Error saving file",
JOptionPane.ERROR_MESSAGE);
}
});
} catch (BadLocationException e) {
System.err.println(e.getMessage());
}
// we are done... get rid of progressbar
status.removeAll();
status.revalidate();
}
}
}
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