com.aurel.track.util.HTMLDiff.java Source code

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Here is the source code for com.aurel.track.util.HTMLDiff.java

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/**
 * Genji Scrum Tool and Issue Tracker
 * Copyright (C) 2015 Steinbeis GmbH & Co. KG Task Management Solutions
    
 * <a href="http://www.trackplus.com">Genji Scrum Tool</a>
 *
 * 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 3 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

/* $Id:$ */

package com.aurel.track.util;

import java.io.StringReader;
import java.io.StringWriter;
import java.net.URISyntaxException;
import java.util.Locale;

import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;

import org.apache.commons.lang3.exception.ExceptionUtils;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
import org.outerj.daisy.diff.HtmlCleaner;
import org.outerj.daisy.diff.XslFilter;
import org.outerj.daisy.diff.html.HTMLDiffer;
import org.outerj.daisy.diff.html.HtmlSaxDiffOutput;
import org.outerj.daisy.diff.html.TextNodeComparator;
import org.outerj.daisy.diff.html.dom.DomTreeBuilder;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;

/**
 *
 */
public class HTMLDiff {

    private static final Logger LOGGER = LogManager.getLogger(HTMLDiff.class);

    private HTMLDiff() {
        // just to hide it
    }

    public static String makeDiff(String newValue, String oldValue, Locale locale) throws URISyntaxException {
        boolean htmlOut = true;
        if (newValue == null) {
            newValue = "";
        } else {
            newValue = newValue.replaceAll("&nbsp;", " ");
        }
        if (oldValue == null || (oldValue != null && oldValue.length() == 0)) {
            return newValue;
        } else {
            oldValue = oldValue.replaceAll("&nbsp;", " ");
        }

        try {
            SAXTransformerFactory tf = (SAXTransformerFactory) TransformerFactory.newInstance();

            TransformerHandler result = tf.newTransformerHandler();
            StringWriter stringWriter = new StringWriter();
            result.setResult(new StreamResult(stringWriter));

            XslFilter filter = new XslFilter();

            ContentHandler postProcess = htmlOut ? filter.xsl(result, "com/aurel/track/util/htmlheader.xsl")
                    : result;

            String prefix = "diff";

            HtmlCleaner cleaner = new HtmlCleaner();

            InputSource oldSource = new InputSource(new StringReader(oldValue));
            InputSource newSource = new InputSource(new StringReader(newValue));

            DomTreeBuilder oldHandler = new DomTreeBuilder();
            cleaner.cleanAndParse(oldSource, oldHandler);
            TextNodeComparator leftComparator = new TextNodeComparator(oldHandler, locale);

            DomTreeBuilder newHandler = new DomTreeBuilder();
            cleaner.cleanAndParse(newSource, newHandler);
            TextNodeComparator rightComparator = new TextNodeComparator(newHandler, locale);

            postProcess.startDocument();
            postProcess.startElement("", "diffreport", "diffreport", new AttributesImpl());
            postProcess.startElement("", "diff", "diff", new AttributesImpl());
            HtmlSaxDiffOutput output = new HtmlSaxDiffOutput(postProcess, prefix);

            HTMLDiffer differ = new HTMLDiffer(output);
            differ.diff(leftComparator, rightComparator);
            postProcess.endElement("", "diff", "diff");
            postProcess.endElement("", "diffreport", "diffreport");
            postProcess.endDocument();
            return stringWriter.toString();
        } catch (Exception e) {
            LOGGER.error(ExceptionUtils.getStackTrace(e));
            if (e.getCause() != null) {
                LOGGER.error(ExceptionUtils.getStackTrace(e.getCause()));
            }
            if (e instanceof SAXException) {
                LOGGER.error(ExceptionUtils.getStackTrace(((SAXException) e).getException()));
            }
        }
        return null;
    }
}