Simple XML tree walker that will clone recursively a node. - Java XML

Java examples for XML:XML Node

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Description

Simple XML tree walker that will clone recursively a node.

Demo Code

/*//from www .  j  a v a 2 s.  c om
 *  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
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 *
 */
//package com.java2s;

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;

public class Main {
    /**
     * 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) {
        Node copy = null;
        final Document doc = parent.getOwnerDocument();

        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;
    }
}

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