Java tutorial
/* * Copyright 2002-2008 the original author or authors. * * 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 com.weibo.wesync.notify.xml; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.List; import org.springframework.util.Assert; import org.w3c.dom.CharacterData; import org.w3c.dom.Comment; import org.w3c.dom.Element; import org.w3c.dom.EntityReference; import org.w3c.dom.Node; import org.w3c.dom.NodeList; /** * Convenience methods for working with the DOM API, in particular for working with DOM Nodes and DOM Elements. * * @author Juergen Hoeller * @author Rob Harrop * @author Costin Leau * @author Arjen Poutsma * @author Luke Taylor * @see org.w3c.dom.Node * @see org.w3c.dom.Element * @since 1.2 */ public abstract class DomUtils { /** * Retrieve all child elements of the given DOM element that match any of the given element names. Only look at the * direct child level of the given element; do not go into further depth (in contrast to the DOM API's * <code>getElementsByTagName</code> method). * * @param ele the DOM element to analyze * @param childEleNames the child element names to look for * @return a List of child <code>org.w3c.dom.Element</code> instances * @see org.w3c.dom.Element * @see org.w3c.dom.Element#getElementsByTagName */ public static List<Element> getChildElementsByTagName(Element ele, String[] childEleNames) { Assert.notNull(ele, "Element must not be null"); Assert.notNull(childEleNames, "Element names collection must not be null"); List<String> childEleNameList = Arrays.asList(childEleNames); NodeList nl = ele.getChildNodes(); List<Element> childEles = new ArrayList<Element>(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (node instanceof Element && nodeNameMatch(node, childEleNameList)) { childEles.add((Element) node); } } return childEles; } /** * Retrieve all child elements of the given DOM element that match the given element name. Only look at the direct * child level of the given element; do not go into further depth (in contrast to the DOM API's * <code>getElementsByTagName</code> method). * * @param ele the DOM element to analyze * @param childEleName the child element name to look for * @return a List of child <code>org.w3c.dom.Element</code> instances * @see org.w3c.dom.Element * @see org.w3c.dom.Element#getElementsByTagName */ public static List<Element> getChildElementsByTagName(Element ele, String childEleName) { return getChildElementsByTagName(ele, new String[] { childEleName }); } /** * Utility method that returns the first child element identified by its name. * * @param ele the DOM element to analyze * @param childEleName the child element name to look for * @return the <code>org.w3c.dom.Element</code> instance, or <code>null</code> if none found */ public static Element getChildElementByTagName(Element ele, String childEleName) { Assert.notNull(ele, "Element must not be null"); Assert.notNull(childEleName, "Element name must not be null"); NodeList nl = ele.getChildNodes(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (node instanceof Element && nodeNameMatch(node, childEleName)) { return (Element) node; } } return null; } /** * Utility method that returns the first child element value identified by its name. * * @param ele the DOM element to analyze * @param childEleName the child element name to look for * @return the extracted text value, or <code>null</code> if no child element found */ public static String getChildElementValueByTagName(Element ele, String childEleName) { Element child = getChildElementByTagName(ele, childEleName); return (child != null ? getTextValue(child) : null); } /** * Retrieve all child elements of the given DOM element * @param ele the DOM element to analyze * @return a List of child <code>org.w3c.dom.Element</code> instances */ public static List<Element> getChildElements(Element ele) { Assert.notNull(ele, "Element must not be null"); NodeList nl = ele.getChildNodes(); List<Element> childEles = new ArrayList<Element>(); for (int i = 0; i < nl.getLength(); i++) { Node node = nl.item(i); if (node instanceof Element) { childEles.add((Element) node); } } return childEles; } /** * Extract the text value from the given DOM element, ignoring XML comments. <p>Appends all CharacterData nodes and * EntityReference nodes into a single String value, excluding Comment nodes. * * @see CharacterData * @see EntityReference * @see Comment */ public static String getTextValue(Element valueEle) { Assert.notNull(valueEle, "Element must not be null"); StringBuilder sb = new StringBuilder(); NodeList nl = valueEle.getChildNodes(); for (int i = 0; i < nl.getLength(); i++) { Node item = nl.item(i); if ((item instanceof CharacterData && !(item instanceof Comment)) || item instanceof EntityReference) { sb.append(item.getNodeValue()); } } return sb.toString(); } /** * Namespace-aware equals comparison. Returns <code>true</code> if either {@link Node#getLocalName} or {@link * Node#getNodeName} equals <code>desiredName</code>, otherwise returns <code>false</code>. */ public static boolean nodeNameEquals(Node node, String desiredName) { Assert.notNull(node, "Node must not be null"); Assert.notNull(desiredName, "Desired name must not be null"); return nodeNameMatch(node, desiredName); } /** Matches the given node's name and local name against the given desired name. */ private static boolean nodeNameMatch(Node node, String desiredName) { return (desiredName.equals(node.getNodeName()) || desiredName.equals(node.getLocalName())); } /** Matches the given node's name and local name against the given desired names. */ private static boolean nodeNameMatch(Node node, Collection desiredNames) { return (desiredNames.contains(node.getNodeName()) || desiredNames.contains(node.getLocalName())); } }