/*
* 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 org.springframework.util.xml;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
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;
import org.springframework.util.Assert;
/**
* 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
* @since 1.2
* @see org.w3c.dom.Node
* @see org.w3c.dom.Element
*/
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 getChildElementsByTagName(Element ele, String[] childEleNames) {
Assert.notNull(ele, "Element must not be null");
Assert.notNull(childEleNames, "Element names collection must not be null");
List childEleNameList = Arrays.asList(childEleNames);
NodeList nl = ele.getChildNodes();
List childEles = new ArrayList();
for (int i = 0; i < nl.getLength(); i++) {
Node node = nl.item(i);
if (node instanceof Element && nodeNameMatch(node, childEleNameList)) {
childEles.add(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 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);
}
/**
* 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");
StringBuffer value = new StringBuffer();
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) {
value.append(item.getNodeValue());
}
}
return value.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()));
}
}