codepointinputmethod.java

input method tool using java

/*
 * @(#)CodePointInputMethod.java	1.6 05/11/17
 * 
 * Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * -Redistribution of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 * 
 * -Redistribution 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 Sun Microsystems, Inc. or the names of contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL 
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MIDROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST 
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, 
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY 
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, 
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility.
 */

/*
 * @(#)CodePointInputMethod.java	1.6 05/11/17
 */

package com.sun.inputmethods.internal.codepointim;
import java.text.AttributedCharacterIterator;
import java.util.Map;

import java.awt.AWTEvent;
import java.awt.Toolkit;
import java.awt.Rectangle;
import java.awt.event.InputMethodEvent;
import java.awt.event.KeyEvent;
import java.awt.font.TextAttribute;
import java.awt.font.TextHitInfo;
import java.awt.im.InputMethodHighlight;
import java.awt.im.spi.InputMethod;
import java.awt.im.spi.InputMethodContext;
import java.io.IOException;
import java.text.AttributedString;
import java.util.Locale;

/**
 * The Code Point Input Method is a simple input method that allows Unicode
 * characters to be entered using their code point or code unit values. See the
 * accompanying file README.txt for more information.
 *
 * @author Brian Beck
 */
public class CodePointInputMethod implements InputMethod {

    private static final int UNSET           = 0;
    private static final int ESCAPE          = 1; // \u0000       - \uFFFF
    private static final int SPECIAL_ESCAPE  = 2; // \U000000     - \U10FFFF
    private static final int SURROGATE_PAIR  = 3; // \uD800\uDC00 - \uDBFF\uDFFF

    private InputMethodContext context;
    private Locale locale;
    private StringBuffer buffer;
    private int insertionPoint;
    private int format = UNSET;


    public CodePointInputMethod() throws IOException {
    }

    /**
     * This is the input method's main routine.  The composed text is stored
     * in buffer.
     */
    public void dispatchEvent(AWTEvent event) {
        // This input method handles KeyEvent only.
        if (!(event instanceof KeyEvent)) {
            return;
        }

        KeyEvent e = (KeyEvent) event;
        int eventID = event.getID();
        boolean notInCompositionMode = buffer.length() == 0;

        if (eventID == KeyEvent.KEY_PRESSED) {
            // If we are not in composition mode, pass through
            if (notInCompositionMode)  {
                return;
            }

            switch (e.getKeyCode()) {
                case KeyEvent.VK_LEFT:
                    moveCaretLeft();
                    break;
                case KeyEvent.VK_RIGHT:
                    moveCaretRight();
                    break;
            }
        } else if (eventID == KeyEvent.KEY_TYPED) {
            char c = e.getKeyChar();

            // If we are not in composition mode, wait a back slash
            if (notInCompositionMode)  {
                // If the type character is not a back slash, pass through
                if (c != '\\') {
                    return;
                }

                startComposition();	// Enter to composition mode
            } else {
                switch (c) { 
                case ' ':	// Exit from composition mode
                    finishComposition();
                    break;
                case '\u007f':	// Delete
                    deleteCharacter();
                    break;
                case '\b':	// BackSpace
                    deletePreviousCharacter();
                    break;
                case '\u001b':	// Escape
                    cancelComposition();
                    break;
                case '\n':	// Return
                case '\t':	// Tab
                    sendCommittedText();
                    break;
                default:
                    composeUnicodeEscape(c);
                    break;
                }
            }
        } else {  // KeyEvent.KEY_RELEASED
            // If we are not in composition mode, pass through
            if (notInCompositionMode)  {
                return;
            }
        }

        e.consume();
    }

    private void composeUnicodeEscape(char c) {
        switch (buffer.length()) {
            case  1:  // \\
                waitEscapeCharacter(c);
                break;
            case 2:  // \\u or \\U
            case 3:  // \\ux or \\Ux
            case 4:  // \\uxx or \\Uxx
                waitDigit(c);
                break;
            case 5:  // \\uxxx or \\Uxxx
                if (format == SPECIAL_ESCAPE) {
                    waitDigit(c);
                } else {
                    waitDigit2(c);
                }
                break;
            case 6:  // \\uxxxx or \\Uxxxx
                if (format == SPECIAL_ESCAPE) {
                    waitDigit(c);
                } else if (format == SURROGATE_PAIR) {
                    waitBackSlashOrLowSurrogate(c);
                } else {
                    beep();
                }
                break;
            case 7:  // \\Uxxxxx
                // Only SPECIAL_ESCAPE format uses this state.
                // Since the second "\\u" of SURROGATE_PAIR format is inserted
                // automatically, users don't have to type these keys.
                waitDigit(c);
                break;
            case 8:  // \\uxxxx\\u
            case 9:  // \\uxxxx\\ux
            case 10: // \\uxxxx\\uxx
            case 11: // \\uxxxx\\uxxx
                if (format == SURROGATE_PAIR) {
                    waitDigit(c);
                } else {
                    beep();
                }
                break;
            default:
                beep();
                break;
        }
    }

    private void waitEscapeCharacter(char c) {
        if (c == 'u' || c == 'U') {
            buffer.append(c);
            insertionPoint++;
            sendComposedText();
            format = (c == 'u') ? ESCAPE : SPECIAL_ESCAPE;
        } else {
            if (c != '\\') {
                buffer.append(c);
                insertionPoint++;
            }
            sendCommittedText();
        }
    }

    private void waitDigit(char c) {
        if (Character.digit(c, 16) != -1) {
            buffer.insert(insertionPoint++, c);
            sendComposedText();
        } else {
            beep();
        }
    }

    private void waitDigit2(char c) {
        if (Character.digit(c, 16) != -1) {
            buffer.insert(insertionPoint++, c);
            char codePoint = (char)getCodePoint(buffer, 2, 5);
            if (Character.isHighSurrogate(codePoint)) {
                format = SURROGATE_PAIR;
                buffer.append("\\u");
                insertionPoint = 8;
            } else {
                format = ESCAPE;
            }
            sendComposedText();
        } else {
            beep();
        }
    }

    private void waitBackSlashOrLowSurrogate(char c) {
        if (insertionPoint == 6) {
            if (c == '\\') {
                buffer.append(c);
                buffer.append('u');
                insertionPoint = 8;
                sendComposedText();
            } else if (Character.digit(c, 16) != -1) {
                buffer.append("\\u");