Java example source code file (WhitespaceBasedBreakIterator.java)

This example Java source code file (WhitespaceBasedBreakIterator.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

breakiterator, characteriterator, done, string, stringcharacteriterator, text, util, whitespacebasedbreakiterator

The WhitespaceBasedBreakIterator.java Java example source code

/*
 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.swing.text;

import java.text.BreakIterator;
import java.text.CharacterIterator;
import java.text.StringCharacterIterator;
import java.util.Arrays;

/**
 * A simple whitespace-based BreakIterator implementation.
 *
 * @author Sergey Groznyh
 */
class WhitespaceBasedBreakIterator extends BreakIterator {
    private char[] text = new char[0];
    private int[] breaks = new int[] { 0 } ;
    private int pos = 0;

    /**
     * Calculate break positions eagerly parallel to reading text.
     */
    public void setText(CharacterIterator ci) {
        int begin = ci.getBeginIndex();
        text = new char[ci.getEndIndex() - begin];
        int[] breaks0 = new int[text.length + 1];
        int brIx = 0;
        breaks0[brIx++] = begin;

        int charIx = 0;
        boolean inWs = false;
        for (char c = ci.first(); c != CharacterIterator.DONE; c = ci.next()) {
            text[charIx] = c;
            boolean ws = Character.isWhitespace(c);
            if (inWs && !ws) {
                breaks0[brIx++] = charIx + begin;
            }
            inWs = ws;
            charIx++;
        }
        if (text.length > 0) {
            breaks0[brIx++] = text.length + begin;
        }
        System.arraycopy(breaks0, 0, breaks = new int[brIx], 0, brIx);
    }

    public CharacterIterator getText() {
        return new StringCharacterIterator(new String(text));
    }

    public int first() {
        return breaks[pos = 0];
    }

    public int last() {
        return breaks[pos = breaks.length - 1];
    }

    public int current() {
        return breaks[pos];
    }

    public int next() {
        return (pos == breaks.length - 1 ? DONE : breaks[++pos]);
    }

    public int previous() {
        return (pos == 0 ? DONE : breaks[--pos]);
    }

    public int next(int n) {
        return checkhit(pos + n);
    }

    public int following(int n) {
        return adjacent(n, 1);
    }

    public int preceding(int n) {
        return adjacent(n, -1);
    }

    private int checkhit(int hit) {
        if ((hit < 0) || (hit >= breaks.length)) {
            return DONE;
        } else {
            return breaks[pos = hit];
        }
    }

    private int adjacent(int n, int bias) {
        int hit = Arrays.binarySearch(breaks, n);
        int offset = (hit < 0 ? (bias < 0 ? -1 : -2) : 0);
        return checkhit(Math.abs(hit) + bias + offset);
    }
}