/FileExtraction/Java_unseen/dice-group_REX/src/main/java/org/aksw/rex/crawler/DOMBuilder.java
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.aksw.rex.crawler;

import java.util.HashMap;
import java.util.Map;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Node;

/**
 * Returns a W3C DOM that exposes the same content as the supplied Jsoup
 * document into a W3C DOM.
 * 
 * @author <a href="mailto:kasper@dfki.de">Walter Kasper</a>
 * 
 */

public class DOMBuilder {
	/**
	 * Returns a W3C DOM that exposes the same content as the supplied Jsoup
	 * document into a W3C DOM.
	 * 
	 * @param jsoupDocument
	 *            The Jsoup document to convert.
	 * @return A W3C Document.
	 */
	public static Document jsoup2DOM(org.jsoup.nodes.Document jsoupDocument) {

		Document document = null;

		try {

			/* Obtain the document builder for the configured XML parser. */
			DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
			DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();

			/* Create a document to contain the content. */
			document = docBuilder.newDocument();
			createDOM(jsoupDocument, document, document, new HashMap<String, String>());

		} catch (ParserConfigurationException pce) {
			throw new RuntimeException(pce);
		}

		return document;
	}

	/**
	 * The internal helper that copies content from the specified Jsoup
	 * <tt>Node</tt> into a W3C {@link Node}.
	 * 
	 * @param node
	 *            The Jsoup node containing the content to copy to the specified
	 *            W3C {@link Node}.
	 * @param out
	 *            The W3C {@link Node} that receives the DOM content.
	 */
	private static void createDOM(org.jsoup.nodes.Node node, Node out, Document doc, Map<String, String> ns) {

		if (node instanceof org.jsoup.nodes.Document) {

			org.jsoup.nodes.Document d = ((org.jsoup.nodes.Document) node);
			for (org.jsoup.nodes.Node n : d.childNodes()) {
				createDOM(n, out, doc, ns);
			}

		} else if (node instanceof org.jsoup.nodes.Element) {

			org.jsoup.nodes.Element e = ((org.jsoup.nodes.Element) node);
			org.w3c.dom.Element _e = doc.createElement(e.tagName());
			out.appendChild(_e);
			org.jsoup.nodes.Attributes atts = e.attributes();

			for (org.jsoup.nodes.Attribute a : atts) {
				String attName = a.getKey();
				// omit xhtml namespace
				if (attName.equals("xmlns")) {
					continue;
				}
				String attPrefix = getNSPrefix(attName);
				if (attPrefix != null) {
					if (attPrefix.equals("xmlns")) {
						ns.put(getLocalName(attName), a.getValue());
					} else if (!attPrefix.equals("xml")) {
						String namespace = ns.get(attPrefix);
						if (namespace == null) {
							// fix attribute names looking like qnames
							attName = attName.replace(':', '_');
						}
					}
				}
				_e.setAttribute(attName, a.getValue());
			}

			for (org.jsoup.nodes.Node n : e.childNodes()) {
				createDOM(n, _e, doc, ns);
			}

		} else if (node instanceof org.jsoup.nodes.TextNode) {

			org.jsoup.nodes.TextNode t = ((org.jsoup.nodes.TextNode) node);
			if (!(out instanceof Document)) {
				out.appendChild(doc.createTextNode(t.text()));
			}
		}
	}

	// some hacks for handling namespace in jsoup2DOM conversion
	private static String getNSPrefix(String name) {
		if (name != null) {
			int pos = name.indexOf(':');
			if (pos > 0) {
				return name.substring(0, pos);
			}
		}
		return null;
	}

	private static String getLocalName(String name) {
		if (name != null) {
			int pos = name.lastIndexOf(':');
			if (pos > 0) {
				return name.substring(pos + 1);
			}
		}
		return name;
	}

}
