UndoRedoTextArea.java

// OO jDREW - An Object Oriented extension of the Java Deductive Reasoning Engine for the Web
// Copyright (C) 2008 Ben Craig
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

package org.ruleml.oojdrew.GUI;

import java.awt.Point;
import java.awt.Toolkit;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.event.ActionEvent;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.AbstractAction;
import javax.swing.JPopupMenu;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.event.UndoableEditEvent;
import javax.swing.event.UndoableEditListener;
import javax.swing.undo.UndoManager;

public class UndoRedoTextArea extends JTextArea implements
        UndoableEditListener, FocusListener, KeyListener {
    private UndoManager undoManager;
    private JPopupMenu contextMenu;

    public UndoRedoTextArea(String text) {
        super(text);

        undoManager = new UndoManager();
        getDocument().addUndoableEditListener(this);
        inititalizeContextMenu();

        addKeyListener(this);
        addFocusListener(this);

        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseReleased(MouseEvent e) {
                requestFocus();
                processMouseClick(e);
            }
        });
    }

    public void undoableEditHappened(UndoableEditEvent e) {
        undoManager.addEdit(e.getEdit());
    }

    private void inititalizeContextMenu() {
        contextMenu = new JPopupMenu("Edit");
        contextMenu.add(new SelectAction(this));
        contextMenu.add(new CutAction(this));
        contextMenu.add(new CopyAction(this));
        contextMenu.add(new PasteAction(this));
        contextMenu.addSeparator();
        contextMenu.add(new UndoAction(this, undoManager));
        contextMenu.add(new RedoAction(this, undoManager));
    }

    public void updateUI() {
        super.updateUI();
        inititalizeContextMenu();
    }

    public void keyPressed(KeyEvent e) {
        int keyCode = e.getKeyCode();

        // Check if CTRL is pressed
        if (e.isControlDown()) {
            try {
                // Do undo action using Ctrl + Y
                if (keyCode == KeyEvent.VK_Z) {
                    undoManager.undo();
                }
                // Do redo action using Ctrl + Y
                else if (keyCode == KeyEvent.VK_Y) {
                    undoManager.redo();
                }
            } catch (Exception ex) {
                // Do nothing
            }
        }
    }

    protected void processMouseClick(MouseEvent e) {
        // Only interested in the right button
        if (SwingUtilities.isRightMouseButton(e)) {
            // Display the menu
            Point pt = SwingUtilities.convertPoint(e.getComponent(),
                    e.getPoint(), this);
            contextMenu.show(this, pt.x, pt.y);
        }
    }

    public void focusGained(FocusEvent fe) {
    }

    public void focusLost(FocusEvent fe) {
    }

    public void keyReleased(KeyEvent e) {
    }

    public void keyTyped(KeyEvent e) {
    }

    class SelectAction extends AbstractAction {
        private final JTextArea textArea;

        public SelectAction(final JTextArea textArea) {
            super("Select all");
            this.textArea = textArea;
        }

        public void actionPerformed(ActionEvent e) {
            textArea.selectAll();
        }

        public boolean isEnabled() {
            return textArea.isEnabled();
        }
    }

    class CopyAction extends AbstractAction {
        private final JTextArea textArea;

        public CopyAction(final JTextArea textArea) {
            super("Copy");
            this.textArea = textArea;
        }

        public void actionPerformed(ActionEvent e) {
            textArea.copy();
        }

        public boolean isEnabled() {
            return textArea.isEnabled();
        }
    }

    class CutAction extends AbstractAction {
        private final JTextArea textArea;

        public CutAction(final JTextArea textArea) {
            super("Cut");
            this.textArea = textArea;
        }

        public void actionPerformed(ActionEvent e) {
            textArea.cut();
        }

        public boolean isEnabled() {
            return textArea.isEditable() && textArea.isEnabled();
        }
    }

    class PasteAction extends AbstractAction {
        private final JTextArea textArea;

        public PasteAction(final JTextArea textArea) {
            super("Paste");
            this.textArea = textArea;
        }

        public void actionPerformed(ActionEvent e) {
            textArea.paste();
        }

        public boolean isEnabled() {
            if (textArea.isEditable() && textArea.isEnabled()) {
                Transferable contents = Toolkit.getDefaultToolkit()
                        .getSystemClipboard().getContents(this);
                return contents.isDataFlavorSupported(DataFlavor.stringFlavor);
            } else {
                return false;
            }
        }
    }

    class UndoAction extends AbstractAction {
        private final JTextArea textArea;
        private UndoManager undoManager;

        public UndoAction(final JTextArea textArea, UndoManager undoManager) {
            super("Undo");
            this.textArea = textArea;
            this.undoManager = undoManager;
        }

        public void actionPerformed(ActionEvent e) {
            undoManager.undo();
        }

        public boolean isEnabled() {
            if (textArea.isEditable() && textArea.isEnabled()) {
                return true;
            } else {
                return false;
            }
        }
    }

    class RedoAction extends AbstractAction {
        private final JTextArea textArea;
        private UndoManager undoManager;

        public RedoAction(final JTextArea textArea, UndoManager undoManager) {
            super("Redo");
            this.textArea = textArea;
            this.undoManager = undoManager;
        }

        public void actionPerformed(ActionEvent e) {
            undoManager.redo();
        }

        public boolean isEnabled() {
            if (textArea.isEditable() && textArea.isEnabled()) {
                return true;
            } else {
                return false;
            }
        }
    }
}