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Flying Saucer is a CSS 2.1 renderer written in Java. This artifact provides implementation of the word-break capability using Apache FOP library

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/*
 * Copyright (C) 2017 Lukas Zaruba, [email protected]
 *
 * This program 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 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */
package org.xhtmlrenderer.fop;

import org.apache.fop.hyphenation.Hyphenation;
import org.apache.fop.hyphenation.HyphenationTree;
import org.apache.fop.hyphenation.Hyphenator;
import org.xhtmlrenderer.css.constants.IdentValue;
import org.xhtmlrenderer.css.style.CalculatedStyle;
import org.xhtmlrenderer.fop.nbsp.NonBreakPointsEnhancer;
import org.xhtmlrenderer.layout.breaker.BreakPoint;
import org.xhtmlrenderer.layout.breaker.BreakPointsProvider;
import org.xhtmlrenderer.layout.breaker.LineBreakingStrategy;
import org.xhtmlrenderer.layout.breaker.ListBreakPointsProvider;
import org.xhtmlrenderer.layout.breaker.UrlAwareLineBreakIterator;

import java.text.BreakIterator;
import java.util.Arrays;
import java.util.Set;
import java.util.TreeSet;

/**
 * Word wrapping capability
 *
 * @author Lukas Zaruba, [email protected]
 */
public class FOPLineBreakingStrategy implements LineBreakingStrategy {

    private static final int SOFT_HYPHEN = '\u00AD';

    private Set getPoints(String text, String lang, CalculatedStyle style) {
        text = new NonBreakPointsEnhancer().enhance(text, lang);
        BreakIterator breakIt = new UrlAwareLineBreakIterator(text);
        Set points = new TreeSet<>();
        int p;
        while ((p = breakIt.next()) != BreakIterator.DONE) {
            points.add(new BreakPoint(p));
        }
        if (style.getHyphens() == IdentValue.NONE) {
            return points;
        }
        if (style.getHyphens() == IdentValue.MANUAL) {
            int index = text.indexOf(SOFT_HYPHEN);
            while (index >= 0) {
                BreakPoint point = new BreakPoint(index);
                addHyphen(point);
                points.add(point);
                index = text.indexOf(SOFT_HYPHEN, index + 1);
            }
            return points;
        }
        if (style.getHyphens() == IdentValue.AUTO) {
            HyphenationTree tree = Hyphenator.getFopHyphenationTree(lang);
            Hyphenation s = tree.hyphenate(text, 2, 2);
            if (s == null) return points;
            for (int i = 0; i < s.getHyphenationPoints().length; i++) {
                int position = s.getHyphenationPoints()[i];
                BreakPoint point = new BreakPoint(position);
                addHyphen(point);
                points.add(point);
            }
        }
        return points;
    }

    @Override
    public BreakPointsProvider getBreakPointsProvider(String text, String lang, CalculatedStyle style) {
        return new ListBreakPointsProvider(Arrays.asList(getPoints(text, lang, style).toArray(new BreakPoint[0])));
    }

    private void addHyphen(BreakPoint p) {
        p.setHyphen("-");
    }

}