/*
* 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 org.apache.tools.ant.taskdefs.optional.junit;
import java.util.Vector;
import org.w3c.dom.Attr;
import org.w3c.dom.CDATASection;
import org.w3c.dom.Comment;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.ProcessingInstruction;
import org.w3c.dom.Text;
/**
* Some utilities that might be useful when manipulating DOM trees.
*
*/
public final class DOMUtil {
/** unused constructor */
private DOMUtil() {
}
/**
* Filter interface to be applied when iterating over a DOM tree.
* Just think of it like a <tt>FileFilter</tt> clone.
*/
public interface NodeFilter {
/**
* @param node the node to check for acceptance.
* @return <tt>true</tt> if the node is accepted by this filter,
* otherwise <tt>false</tt>
*/
boolean accept(Node node);
}
/**
* list a set of node that match a specific filter. The list can be made
* recursively or not.
* @param parent the parent node to search from
* @param filter the filter that children should match.
* @param recurse <tt>true</tt> if you want the list to be made recursively
* otherwise <tt>false</tt>.
* @return the node list that matches the filter.
*/
public static NodeList listChildNodes(Node parent, NodeFilter filter, boolean recurse) {
NodeListImpl matches = new NodeListImpl();
NodeList children = parent.getChildNodes();
if (children != null) {
final int len = children.getLength();
for (int i = 0; i < len; i++) {
Node child = children.item(i);
if (filter.accept(child)) {
matches.addElement(child);
}
if (recurse) {
NodeList recmatches = listChildNodes(child, filter, recurse);
final int reclength = recmatches.getLength();
for (int j = 0; j < reclength; j++) {
matches.addElement(recmatches.item(i));
}
}
}
}
return matches;
}
/** custom implementation of a nodelist */
public static class NodeListImpl extends Vector<Node> implements NodeList {
private static final long serialVersionUID = 3175749150080946423L;
/**
* Get the number of nodes in the list.
* @return the length of the list.
*/
@Override
public int getLength() {
return size();
}
/**
* Get a particular node.
* @param i the index of the node to get.
* @return the node if the index is in bounds, null otherwise.
*/
@Override
public Node item(int i) {
try {
return elementAt(i);
} catch (ArrayIndexOutOfBoundsException e) {
return null; // conforming to NodeList interface
}
}
}
/**
* return the attribute value of an element.
* @param node the node to get the attribute from.
* @param name the name of the attribute we are looking for the value.
* @return the value of the requested attribute or <tt>null</tt> if the
* attribute was not found or if <tt>node</tt> is not an <tt>Element</tt>.
*/
public static String getNodeAttribute(Node node, String name) {
if (node instanceof Element) {
Element element = (Element) node;
return element.getAttribute(name);
}
return null;
}
/**
* Iterate over the children of a given node and return the first node
* that has a specific name.
* @param parent the node to search child from. Can be <tt>null</tt>.
* @param tagname the child name we are looking for. Cannot be <tt>null</tt>.
* @return the first child that matches the given name or <tt>null</tt> if
* the parent is <tt>null</tt> or if a child does not match the
* given name.
*/
public static Element getChildByTagName (Node parent, String tagname) {
if (parent == null) {
return null;
}
NodeList childList = parent.getChildNodes();
final int len = childList.getLength();
for (int i = 0; i < len; i++) {
Node child = childList.item(i);
if (child != null && child.getNodeType() == Node.ELEMENT_NODE
&& child.getNodeName().equals(tagname)) {
return (Element) child;
}
}
return null;
}
/**
* Simple tree walker that will clone recursively a node. This is to
* avoid using parser-specific API such as Sun's <tt>changeNodeOwner</tt>
* when we are dealing with DOM L1 implementations since <tt>cloneNode(boolean)</tt>
* will not change the owner document.
* <tt>changeNodeOwner</tt> is much faster and avoid the costly cloning process.
* <tt>importNode</tt> is in the DOM L2 interface.
* @param parent the node parent to which we should do the import to.
* @param child the node to clone recursively. Its clone will be
* appended to <tt>parent</tt>.
* @return the cloned node that is appended to <tt>parent</tt>
*/
public static Node importNode(Node parent, Node child) {
final Document doc = parent.getOwnerDocument();
Node copy;
switch (child.getNodeType()) {
case Node.CDATA_SECTION_NODE:
copy = doc.createCDATASection(((CDATASection) child).getData());
break;
case Node.COMMENT_NODE:
copy = doc.createComment(((Comment) child).getData());
break;
case Node.DOCUMENT_FRAGMENT_NODE:
copy = doc.createDocumentFragment();
break;
case Node.ELEMENT_NODE:
final Element elem = doc.createElement(((Element) child).getTagName());
copy = elem;
final NamedNodeMap attributes = child.getAttributes();
if (attributes != null) {
final int size = attributes.getLength();
for (int i = 0; i < size; i++) {
final Attr attr = (Attr) attributes.item(i);
elem.setAttribute(attr.getName(), attr.getValue());
}
}
break;
case Node.ENTITY_REFERENCE_NODE:
copy = doc.createEntityReference(child.getNodeName());
break;
case Node.PROCESSING_INSTRUCTION_NODE:
final ProcessingInstruction pi = (ProcessingInstruction) child;
copy = doc.createProcessingInstruction(pi.getTarget(), pi.getData());
break;
case Node.TEXT_NODE:
copy = doc.createTextNode(((Text) child).getData());
break;
default:
// this should never happen
throw new IllegalStateException("Invalid node type: " + child.getNodeType());
}
// okay we have a copy of the child, now the child becomes the parent
// and we are iterating recursively over its children.
try {
final NodeList children = child.getChildNodes();
if (children != null) {
final int size = children.getLength();
for (int i = 0; i < size; i++) {
final Node newChild = children.item(i);
if (newChild != null) {
importNode(copy, newChild);
}
}
}
} catch (DOMException ignored) {
// Ignore
}
// bingo append it. (this should normally not be done here)
parent.appendChild(copy);
return copy;
}
}