awsapi/src/com/cloud/bridge/util/XmlHelper.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 com.cloud.bridge.util;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.util.Properties;

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

import org.apache.log4j.Logger;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

public class XmlHelper {
    protected static Logger logger = Logger.getLogger(XmlHelper.class);

    public static Document parse(String xmlContent) throws IOException {
        ByteArrayInputStream is = new ByteArrayInputStream(xmlContent.getBytes("UTF-8"));
        return parse(is);
    }

    public static Document parse(File file) throws IOException {
        try {
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            factory.setCoalescing(true);
            factory.setIgnoringComments(true);
            factory.setIgnoringElementContentWhitespace(true);
            factory.setNamespaceAware(true);
            DocumentBuilder parser = factory.newDocumentBuilder();
            return parser.parse(file);
        } catch (ParserConfigurationException e) {
            throw new IOException(e);
        } catch (SAXException e) {
            throw new IOException(e);
        }
    }

    public static Document parse(InputStream is) throws IOException {
        try {
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            factory.setCoalescing(true);
            factory.setIgnoringComments(true);
            factory.setIgnoringElementContentWhitespace(true);
            factory.setNamespaceAware(true);
            DocumentBuilder parser = factory.newDocumentBuilder();
            InputSource in = new InputSource(is);
            return parser.parse(in);
        } catch (ParserConfigurationException e) {
            throw new IOException(e);
        } catch (SAXException e) {
            throw new IOException(e);
        }
    }

    public static Document newDocument() {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        dbf.setNamespaceAware(true);
        DocumentBuilder builder;
        try {
            builder = dbf.newDocumentBuilder();
            Document document = builder.newDocument();
            return document;
        } catch (ParserConfigurationException e) {
            logger.error("Unexpected exception " + e.getMessage(), e);
        }

        return null;
    }

    public static Node getRootNode(Document doc) {
        NodeList l = doc.getChildNodes();
        if (l != null && l.getLength() == 1)
            return l.item(0);

        return null;
    }

    public static Node getChildNode(Node parentNode, String childElementName) {
        NodeList l = parentNode.getChildNodes();
        for (int i = 0; i < l.getLength(); i++) {
            Node node = l.item(i);
            if (node.getNodeName().equals(childElementName))
                return node;
        }
        return null;
    }

    public static String getChildNodeTextContent(Node parentNode, String childElementName) {
        Node node = getChildNode(parentNode, childElementName);
        if (node != null)
            return node.getTextContent();
        return null;
    }

    public static String getAttribute(Node node, String name) {
        NamedNodeMap attributes = node.getAttributes();
        Node attrNode = attributes.getNamedItem(name);
        if (attrNode != null)
            return attrNode.getNodeValue();
        return null;
    }

    public static String toXML(Node node) {
        if (node != null) {
            Transformer transformer = newTransformer();
            try {
                StringWriter sw = new StringWriter();
                transformer.transform(new DOMSource(node), new StreamResult(sw));
                return sw.toString();
            } catch (TransformerException e) {
                logger.error("Unexpected exception " + e.getMessage(), e);
            }
        }
        return StringHelper.EMPTY_STRING;
    }

    public static Transformer newTransformer() {
        return newTransformer("UTF-8", false);
    }

    public static Transformer newTransformer(String encoding, boolean indent) {
        try {
            Transformer transformer = TransformerFactory.newInstance().newTransformer();
            Properties properties = transformer.getOutputProperties();

            properties.setProperty(OutputKeys.ENCODING, encoding);
            properties.setProperty(OutputKeys.METHOD, "XML");
            properties.setProperty(OutputKeys.VERSION, "1.0");
            if (indent)
                properties.setProperty(OutputKeys.INDENT, "YES");
            else
                properties.setProperty(OutputKeys.INDENT, "NO");
            transformer.setOutputProperties(properties);
            return transformer;
        } catch (TransformerConfigurationException e) {
            logger.error("Unexpected exception " + e.getMessage(), e);
        }

        return null;
    }
}