mjtextarea.java

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/*
 * Copyright (C) 2003 Adam Olsen
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation; either version 1, or (at your option) any later version.
 *
 * This program 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 General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 675 Mass
 * Ave, Cambridge, MA 02139, USA.
 */

package com.valhalla.gui;

import javax.swing.*;
import java.awt.event.ActionEvent;

public class MJTextArea extends JTextArea
{
    public MJTextArea(int rows, int cols)
    {
        super(rows, cols);
        CopyPasteContextMenu.registerComponent(this, true);
        initializeKeyboardBindings();
    }

    public MJTextArea()
    {
        CopyPasteContextMenu.registerComponent(this, true);
        initializeKeyboardBindings();
    }

    /**
     * adds keyboard action to this MJTextArea
     * @param aKeyEventAction to add
     */
    public void addKeyboardBindingAction(KeyBindingAction aKeyEventAction)
    {
        getInputMap().put(KeyStroke.getKeyStroke(aKeyEventAction.getKeyEvent(),
            aKeyEventAction.getKeyModifier()), aKeyEventAction.getName());
        getActionMap().put(aKeyEventAction.getName(), aKeyEventAction);
    }

    /**
     * initialization of "default" keybindings. As default JTextArea that MJTextArea inherits
     * from does not contain all handy shortcuts, they can be added here
     */
    private void initializeKeyboardBindings()
    {
        // add Ctrl-Backspace binding to delete the last word
        addKeyboardBindingAction(new KeyBindingAction("ctrlBackspace",
            java.awt.event.KeyEvent.VK_BACK_SPACE,
            java.awt.Event.CTRL_MASK)
        {
            public void actionPerformed(ActionEvent e)
            {
                int lastSpaceIndex = getText().lastIndexOf(' ');
                int lastNLIndex = getText().lastIndexOf('\n');

                String modifiedTextContents = "";
                //modifiedTextContents.
                if (lastSpaceIndex != -1 || lastNLIndex != -1) // if this is not the last word left
                {
                    int lastIndex = (lastSpaceIndex > lastNLIndex ? lastSpaceIndex : lastNLIndex);
                    modifiedTextContents = getText().substring(0, lastIndex + 1 );
                }
                setText(modifiedTextContents);
                setCaretPosition(modifiedTextContents.length());
                repaint();
            }
        });
    }

    /**
     * simple abstract class to encapsulate key bindings and their actions. The reason for it is
     * to have all the information on key binding: key event, modifier and the action in one place
     */
    abstract class KeyBindingAction extends AbstractAction
    {
        private int keyEvent;
        private int keyModifier;

        public KeyBindingAction(String name, int aKeyEvent, int aKeyModifier)
        {
            super(name);
            keyEvent = aKeyEvent;
            keyModifier = aKeyModifier;
        }

        public int getKeyEvent()
        {
            return keyEvent;
        }

        public int getKeyModifier()
        {
            return keyModifier;
        }

        public String getName()
        {
            return (String) getValue(Action.NAME);
        }
    }
}