Java JTextComponent Word getNextWord(JTextComponent c, int offs)

Description

Determines the start of the next word for the given location.

License

Open Source License

Parameter

Parameter	Description
c	the editor
offs	the offset in the document >= 0

Return

the location in the model of the word start >= 0

Declaration

public static final int getNextWord(JTextComponent c, int offs) throws BadLocationException 

Method Source Code

//package com.java2s;
/*/*w  ww.  jav  a  2  s . co  m*/
 * @(#)Utilities.java   1.38 01/12/03
 *
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

import javax.swing.text.*;

import java.text.*;

public class Main {
    /**
     * Determines the start of the next word for the given location.
     * Uses BreakIterator.getWordInstance() to actually get the words.
     * 
     * @param c the editor
     * @param offs the offset in the document >= 0
     * @return the location in the model of the word start >= 0
     * @exception BadLocationException if the offset is out of range
     */
    public static final int getNextWord(JTextComponent c, int offs) throws BadLocationException {
        int nextWord;
        Element line = getParagraphElement(c, offs);
        for (nextWord = getNextWordInParagraph(c, line, offs,
                false); nextWord == BreakIterator.DONE; nextWord = getNextWordInParagraph(c, line, offs, true)) {

            // didn't find in this line, try the next line
            offs = line.getEndOffset();
            line = getParagraphElement(c, offs);
        }
        return nextWord;
    }

    /**
     * Determines the element to use for a paragraph/line.
     *
     * @param c the editor
     * @param offs the starting offset in the document >= 0
     * @return the element
     */
    public static final Element getParagraphElement(JTextComponent c, int offs) {
        Document doc = c.getDocument();
        if (doc instanceof StyledDocument) {
            return ((StyledDocument) doc).getParagraphElement(offs);
        }
        Element map = doc.getDefaultRootElement();
        int index = map.getElementIndex(offs);
        Element paragraph = map.getElement(index);
        if ((offs >= paragraph.getStartOffset()) && (offs < paragraph.getEndOffset())) {
            return paragraph;
        }
        return null;
    }

    /**
     * Finds the next word in the given elements text.  The first
     * parameter allows searching multiple paragraphs where even
     * the first offset is desired.
     * Returns the offset of the next word, or BreakIterator.DONE
     * if there are no more words in the element.
     */
    static int getNextWordInParagraph(JTextComponent c, Element line, int offs, boolean first)
            throws BadLocationException {
        if (line == null) {
            throw new BadLocationException("No more words", offs);
        }
        Document doc = line.getDocument();
        int lineStart = line.getStartOffset();
        int lineEnd = Math.min(line.getEndOffset(), doc.getLength());
        if ((offs >= lineEnd) || (offs < lineStart)) {
            throw new BadLocationException("No more words", offs);
        }
        String s = doc.getText(lineStart, lineEnd - lineStart);
        BreakIterator words = BreakIterator.getWordInstance(c.getLocale());
        words.setText(s);
        if ((first && (words.first() == (offs - lineStart)))
                && (!Character.isWhitespace(s.charAt(words.first())))) {

            return offs;
        }
        int wordPosition = words.following(offs - lineStart);
        if ((wordPosition == BreakIterator.DONE) || (wordPosition >= s.length())) {
            // there are no more words on this line.
            return BreakIterator.DONE;
        }
        // if we haven't shot past the end... check to 
        // see if the current boundary represents whitespace.
        // if so, we need to try again
        char ch = s.charAt(wordPosition);
        if (!Character.isWhitespace(ch)) {
            return lineStart + wordPosition;
        }

        // it was whitespace, try again.  The assumption
        // is that it must be a word start if the last
        // one had whitespace following it.
        wordPosition = words.next();
        if (wordPosition != BreakIterator.DONE) {
            offs = lineStart + wordPosition;
            if (offs != lineEnd) {
                return offs;
            }
        }
        return BreakIterator.DONE;
    }
}

Related

1. getNextWordInParagraph(JTextComponent c, Element line, int offs, boolean first)
2. getPartialWordBeforePos(JTextComponent editor, int iPos)
3. getPreviousWord(JTextComponent editor, int iOffset)
4. getWordAtCaret(JTextComponent editor)