XMLUtils.java

/*
 * RED5 Open Source Flash Server - http://code.google.com/p/red5/
 * 
 * Copyright 2006-2012 by respective authors (see below). All rights reserved.
 * 
 * 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.red5.io.utils;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;

/**
 * Misc XML utils
 *
 * @author The Red5 Project (red5@osflash.org)
 * @author Luke Hubbard, Codegent Ltd (luke@codegent.com)
 * @author Paul Gregoire (mondain@gmail.com)
 */
public class XMLUtils {
    /**
     * Logger
     */
	protected static Logger log = LoggerFactory.getLogger(XMLUtils.class);
	
    /**
     * Converts string representation of XML into Document
     * @param str              String representation of XML
     * @return                 DOM object
     * @throws IOException     I/O exception
     */
    public static Document stringToDoc(String str) throws IOException {
    	if (StringUtils.isNotEmpty(str)) {
    		try {    			
    			Reader reader = new StringReader(str);
    			
    			DocumentBuilder db = DocumentBuilderFactory.newInstance()
    					.newDocumentBuilder();
    			Document doc = db.parse(new InputSource(reader));
    			    			
    			reader.close();
    	        
    			return doc;
    		} catch (Exception ex) {
    			log.debug("String: {}", str);
    			throw new IOException(String.format("Error converting from string to doc %s", ex.getMessage()));
    		}
    	} else {
    		throw new IOException("Error - could not convert empty string to doc");
    	}
	}

    /**
     * Converts doc to String
     * @param dom            DOM object to convert
     * @return               XML as String
     */
    public static String docToString(Document dom) {
		return XMLUtils.docToString1(dom);
	}

	/**
	 * Convert a DOM tree into a String using Dom2Writer
     * @return               XML as String
     * @param dom            DOM object to convert
     */
	public static String docToString1(Document dom) {
		StringWriter sw = new StringWriter();
		DOM2Writer.serializeAsXML(dom, sw);
		return sw.toString();
	}

	/**
	 * Convert a DOM tree into a String using transform
     * @param domDoc                  DOM object
     * @throws java.io.IOException    I/O exception
     * @return                        XML as String
     */
	public static String docToString2(Document domDoc) throws IOException {
		try {
			TransformerFactory transFact = TransformerFactory.newInstance();
			Transformer trans = transFact.newTransformer();
			trans.setOutputProperty(OutputKeys.INDENT, "no");
			StringWriter sw = new StringWriter();
			Result result = new StreamResult(sw);
			trans.transform(new DOMSource(domDoc), result);
			return sw.toString();
		} catch (Exception ex) {
			throw new IOException(String.format("Error converting from doc to string %s", ex.getMessage()));
		}
	}

}