HtmlTestFixture.java

/*
 * Copyright 2009 Guy Van den Broeck
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.outerj.daisy.diff.html;

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

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

import org.outerj.daisy.diff.helper.NekoHtmlParser;
import org.outerj.daisy.diff.html.dom.DomTreeBuilder;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;

/**
 * TestCase for HTML diffing. Can be used in unit tests. See HTMLDifferText for example.
 * 
 * @author kapelonk
 * @version 04 Jul 2011
 *
 */
public class HtmlTestFixture {

	/**
	 * This class has only static methods.
	 */
	private HtmlTestFixture() {
		// Disabled
	}
	
	/**
	 * Performs HTML diffing on two HTML strings. Notice that the input strings
	 * are "cleaned-up" first (e.g. all html tags are converted to lowercase).
	 * 
	 * @param first
	 *            original html text
	 * @param second
	 *            modified html text
	 * @return the result
	 * @throws Exception
	 *             something went wrong.
	 */
	public static String diff(String first, String second) throws Exception {
		StringWriter finalResult = new StringWriter();
		SAXTransformerFactory tf = (SAXTransformerFactory) SAXTransformerFactory.newInstance();

		TransformerHandler result = tf.newTransformerHandler();
        result.getTransformer().setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        result.getTransformer().setOutputProperty(OutputKeys.INDENT, "yes");
        result.getTransformer().setOutputProperty(OutputKeys.METHOD, "html");
        result.getTransformer().setOutputProperty(OutputKeys.ENCODING, TestHelper.ENCODING);
        result.setResult(new StreamResult(finalResult));
        
        ContentHandler postProcess = result;
        
        Locale locale = Locale.getDefault();
        String prefix = "diff";
        
        NekoHtmlParser cleaner = new NekoHtmlParser();

        InputSource oldSource = new InputSource(new StringReader(
        		first));
        InputSource newSource = new InputSource(new StringReader(
        		second));

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

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

        HtmlSaxDiffOutput output = new HtmlSaxDiffOutput(postProcess,
                prefix);
        
        //Debug code
//        LCSSettings settings = new LCSSettings();
//        settings.setUseGreedyMethod(false);
//        // settings.setPowLimit(1.5);
//        // settings.setTooLong(100000*100000);
//
//        RangeDifference[] differences = RangeDifferencer.findDifferences(
//                settings, leftComparator, rightComparator);
//        LOG.info(">>>>Number of diffs is "+differences.length);
        //End of debug code
        
        HTMLDiffer differ = new HTMLDiffer(output);
        differ.diff(leftComparator, rightComparator);
        
        return finalResult.toString();

	}
	
	/**
	 * Performs HTML diffing on two HTML strings. Notice that the input strings
	 * are "cleaned-up" first (e.g. all html tags are converted to lowercase).
	 * 
	 * @param ancestor 
	 * 	          the ancestor html text of the two first and second html texts
	 * @param first
	 *            original html text
	 * @param second
	 *            modified html text
	 * @return the result
	 * @throws Exception
	 *             something went wrong.
	 */
	public static String diff(String ancestor, String first, String second) throws Exception {
		StringWriter finalResult = new StringWriter();
		SAXTransformerFactory tf = (SAXTransformerFactory) SAXTransformerFactory.newInstance();

		TransformerHandler result = tf.newTransformerHandler();
        result.getTransformer().setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
        result.getTransformer().setOutputProperty(OutputKeys.INDENT, "yes");
        result.getTransformer().setOutputProperty(OutputKeys.METHOD, "html");
        result.getTransformer().setOutputProperty(OutputKeys.ENCODING, TestHelper.ENCODING);
        result.setResult(new StreamResult(finalResult));
		
		ContentHandler postProcess = result;
		
		Locale locale = Locale.getDefault();
		String prefix = "diff";
		
		NekoHtmlParser cleaner = new NekoHtmlParser();
		
		InputSource ancestorSource = new InputSource(new StringReader(
				ancestor));
		InputSource oldSource = new InputSource(new StringReader(
				first));
		InputSource newSource = new InputSource(new StringReader(
				second));
		
		DomTreeBuilder ancestorHandler = new DomTreeBuilder();
		cleaner.parse(ancestorSource, ancestorHandler);
		TextNodeComparator ancestorComparator = new TextNodeComparator(
				ancestorHandler, locale);
		
		DomTreeBuilder oldHandler = new DomTreeBuilder();
		cleaner.parse(oldSource, oldHandler);
		TextNodeComparator leftComparator = new TextNodeComparator(
				oldHandler, locale);
		
		DomTreeBuilder newHandler = new DomTreeBuilder();
		cleaner.parse(newSource, newHandler);
		TextNodeComparator rightComparator = new TextNodeComparator(
				newHandler, locale);
		
		HtmlSaxDiffOutput output = new HtmlSaxDiffOutput(postProcess,
				prefix);
		
		//Debug code
//        LCSSettings settings = new LCSSettings();
//        settings.setUseGreedyMethod(false);
//        // settings.setPowLimit(1.5);
//        // settings.setTooLong(100000*100000);
//
//        RangeDifference[] differences = RangeDifferencer.findDifferences(
//                settings, leftComparator, rightComparator);
//        LOG.info(">>>>Number of diffs is "+differences.length);
		//End of debug code
		
		HTMLDiffer differ = new HTMLDiffer(output);
		differ.diff(ancestorComparator, leftComparator, rightComparator);
		
		return finalResult.toString();
	}
}