content: /*
   * 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.aliyuncs.fc.utils;
  
  import java.io.Closeable;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.StringReader;
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.xml.XMLConstants;
  import javax.xml.parsers.DocumentBuilder;
  import javax.xml.parsers.DocumentBuilderFactory;
  import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.transform.Source;
  import javax.xml.transform.dom.DOMSource;
  import javax.xml.transform.stream.StreamSource;
  import javax.xml.validation.Schema;
  import javax.xml.validation.SchemaFactory;
  import javax.xml.validation.Validator;
  
  import org.w3c.dom.Document;
  import org.w3c.dom.Element;
  import org.w3c.dom.Node;
  import org.w3c.dom.NodeList;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  
  public final class XmlUtils {
  
      public static Document getDocument(String payload)
          throws ParserConfigurationException, SAXException, IOException {
          if (payload == null || payload.length() < 1) {
              return null;
          }
  
          StringReader sr = new StringReader(payload);
          InputSource source = new InputSource(sr);
  
          return getDocument(source, null);
      }
  
      public static Document getDocument(InputSource xml, InputStream xsd)
          throws ParserConfigurationException, SAXException, IOException {
          Document doc = null;
  
          try {
              DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
              if (xsd != null) {
                  dbf.setNamespaceAware(true);
              }
  
              DocumentBuilder builder = dbf.newDocumentBuilder();
              doc = builder.parse(xml);
  
              if (xsd != null) {
                  validateXml(doc, xsd);
              }
          } finally {
              closeStream(xml.getByteStream());
          }
  
          return doc;
      }
  
      public static Element getRootElementFromString(String payload)
          throws ParserConfigurationException, SAXException, IOException {
  
          return getDocument(payload).getDocumentElement();
      }
  
  
      public static List<Element> getChildElements(Element parent, String tagName) {
          if (null == parent) {
              return null;
          }
          NodeList nodes = parent.getElementsByTagName(tagName);
          List<Element> elements = new ArrayList<Element>();
  
          for (int i = 0; i < nodes.getLength(); i++) {
              Node node = nodes.item(i);
              if (node.getParentNode() == parent) {
                  elements.add((Element) node);
              }
          }
  
          return elements;
      }
  
  
      public static List<Element> getChildElements(Element parent) {
          if (null == parent) {
              return null;
          }
  
          NodeList nodes = parent.getChildNodes();
          List<Element> elements = new ArrayList<Element>();
  
          for (int i = 0; i < nodes.getLength(); i++) {
              Node node = nodes.item(i);
              if (node.getNodeType() == Node.ELEMENT_NODE) {
                  elements.add((Element) node);
              }
          }
  
          return elements;
      }
  
      public static void validateXml(InputStream xml, InputStream xsd)
          throws SAXException, IOException, ParserConfigurationException {
          try {
              DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
              dbf.setNamespaceAware(true);
              Document doc = dbf.newDocumentBuilder().parse(xml);
              validateXml(doc, xsd);
          } finally {
              closeStream(xml);
              closeStream(xsd);
          }
      }
  
      public static void validateXml(Node root, InputStream xsd)
          throws SAXException, IOException {
          try {
              Source source = new StreamSource(xsd);
              Schema schema = SchemaFactory.newInstance(
                  XMLConstants.W3C_XML_SCHEMA_NS_URI).newSchema(source);
  
              Validator validator = schema.newValidator();
              validator.validate(new DOMSource(root));
          } finally {
              closeStream(xsd);
          }
      }
  
      private static void closeStream(Closeable stream) {
          if (stream != null) {
              try {
                  stream.close();
              } catch (IOException e) {
              }
          }
      }
  }