Java tutorial
//package com.java2s; /* * JBoss, Home of Professional Open Source * Copyright 2005, JBoss Inc., and individual contributors as indicated * by the @authors tag. See the copyright.txt in the distribution for a * full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import java.util.ArrayList; import java.util.Iterator; public class Main { /** * Macro to get the content of a unique child element. * * @param element The parent element. * @param tagName The name of the desired child. * @return The element content or null. */ public static String getUniqueChildContent(Element element, String tagName) throws Exception { return getElementContent(getUniqueChild(element, tagName)); } /** * Get the content of the given element. * * @param element The element to get the content for. * @return The content of the element or null. */ public static String getElementContent(final Element element) throws Exception { return getElementContent(element, null); } /** * Get the content of the given element. * * @param element The element to get the content for. * @param defaultStr The default to return when there is no content. * @return The content of the element or the default. */ public static String getElementContent(Element element, String defaultStr) throws Exception { if (element == null) return defaultStr; NodeList children = element.getChildNodes(); String result = ""; for (int i = 0; i < children.getLength(); i++) { if (children.item(i).getNodeType() == Node.TEXT_NODE || children.item(i).getNodeType() == Node.CDATA_SECTION_NODE) { result += children.item(i).getNodeValue(); } else if (children.item(i).getNodeType() == Node.COMMENT_NODE) { // Ignore comment nodes } } return result.trim(); } /** * Gets the child of the specified element having the specified unique * name. If there are more than one children elements with the same name * and exception is thrown. * * @param element The parent element * @param tagName The name of the desired child * @return The named child. * * @throws Exception Child was not found or was not unique. */ public static Element getUniqueChild(Element element, String tagName) throws Exception { Iterator<Element> goodChildren = getChildrenByTagName(element, tagName); if (goodChildren != null && goodChildren.hasNext()) { Element child = goodChildren.next(); if (goodChildren.hasNext()) { throw new Exception("expected only one " + tagName + " tag"); } return child; } else { throw new Exception("expected one " + tagName + " tag"); } } /** * Returns an iterator over the children of the given element with * the given tag name. * * @param element The parent element * @param tagName The name of the desired child * @return An interator of children or null if element is null. */ public static Iterator<Element> getChildrenByTagName(Element element, String tagName) { if (element == null) return null; // getElementsByTagName gives the corresponding elements in the whole // descendance. We want only children NodeList children = element.getChildNodes(); ArrayList<Element> goodChildren = new ArrayList<Element>(); for (int i = 0; i < children.getLength(); i++) { Node currentChild = children.item(i); if (currentChild.getNodeType() == Node.ELEMENT_NODE && ((Element) currentChild).getTagName().equals(tagName)) { goodChildren.add((Element) currentChild); } } return goodChildren.iterator(); } }