package urdo;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.KeyStroke;
import javax.swing.UIManager;
import javax.swing.WindowConstants;
import javax.swing.event.UndoableEditEvent;
import javax.swing.event.UndoableEditListener;
import javax.swing.undo.CannotRedoException;
import javax.swing.undo.CannotUndoException;
import javax.swing.undo.UndoManager;

public class NewJFrame extends javax.swing.JFrame {
?private JPanel jp1;

?private JButton jb1;

?private JButton jb2;

?private JMenuItem jm12;

?private JMenuItem jm11;

?private JMenu jm;

?private JMenuBar jMenuBar1;

?private JTextArea jta;

?private JScrollPane jsp;

?/**
? * Auto-generated main method to display this JFrame
? */
?public static void main(String[] args) {
??NewJFrame inst = new NewJFrame();
??inst.setVisible(true);
?}

?public NewJFrame() {
??super();
??initGUI();
?}

?private void initGUI() {
??try {
???setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
???{
????jMenuBar1 = new JMenuBar();
????setJMenuBar(jMenuBar1);
????{
?????jm = new JMenu();
?????jMenuBar1.add(jm);
?????jm.setText("jm");
?????{
??????jm11 = new JMenuItem(redoAction);
??????jm.add(jm11);
??????jm11.setText("re");
?????}
?????{
??????jm12 = new JMenuItem(undoAction);
??????jm.add(jm12);
??????jm12.setText("undo");
?????}
?????jm12.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Z,
???????InputEvent.CTRL_MASK));
????}
???}
???{
????jp1 = new JPanel();
????getContentPane().add(jp1, BorderLayout.NORTH);
????jp1.setPreferredSize(new java.awt.Dimension(392, 35));
????{
?????jb1 = new JButton(redoAction);
?????jp1.add(jb1);
?????jb1.setText("redo");
????}
????//????jb1.registerKeyboardAction(redoAction, KeyStroke.getKeyStroke(
????//??????KeyEvent.VK_Y, KeyEvent.CTRL_DOWN_MASK, true),
????//??????JComponent.WHEN_IN_FOCUSED_WINDOW);
????{
?????jb2 = new JButton(undoAction);
?????jp1.add(jb2);
?????jb2.setText("undo");
????}
????//????jb2.registerKeyboardAction(undoAction, KeyStroke.getKeyStroke(
????//??????KeyEvent.VK_Z, KeyEvent.CTRL_DOWN_MASK, true),
????//??????JComponent.WHEN_IN_FOCUSED_WINDOW);

???}
???{
????jsp = new JScrollPane();
????getContentPane().add(jsp, BorderLayout.CENTER);
????{
?????jta = new JTextArea();
?????jsp.setViewportView(jta);
?????jta.getDocument().addUndoableEditListener(undoHandler);
????}
???}
???pack();
???setSize(400, 300);
??} catch (Exception e) {
???e.printStackTrace();
??}
?}

?protected UndoableEditListener undoHandler = new UndoHandler();

?protected UndoManager undo = new UndoManager();

?private UndoAction undoAction = new UndoAction();

?private RedoAction redoAction = new RedoAction();

?class UndoHandler implements UndoableEditListener {

??/**
?? * Messaged when the Document has created an edit, the edit is
?? * added to <code>undo</code>, an instance of UndoManager.
?? */
??public void undoableEditHappened(UndoableEditEvent e) {
???undo.addEdit(e.getEdit());
???undoAction.update();
???redoAction.update();
??}
?}

?class UndoAction extends AbstractAction {
??public UndoAction() {
???super();
???setEnabled(false);
??}

??public void actionPerformed(ActionEvent e) {
???try {
????undo.undo();
???} catch (CannotUndoException ex) {
????ex.printStackTrace();
???}
???update();
???redoAction.update();
??}

??protected void update() {
???if (undo.canUndo()) {
????setEnabled(true);
????//????System.out.println(undo.getUndoPresentationName());
????putValue(Action.NAME, undo.getUndoPresentationName());
???} else {
????setEnabled(false);
????putValue(Action.NAME, "撤消");
???}
??}
?}

?class RedoAction extends AbstractAction {
??public RedoAction() {
???super();
???setEnabled(false);
??}

??public void actionPerformed(ActionEvent e) {
???try {
????undo.redo();
???} catch (CannotRedoException ex) {
????ex.printStackTrace();
???}
???update();
???undoAction.update();
??}

??protected void update() {
???if (undo.canRedo()) {
????setEnabled(true);
????putValue(Action.NAME, undo.getRedoPresentationName());
???} else {
????setEnabled(false);
????putValue(Action.NAME, "重做");
???}
??}
?}
}