Java XPath Create getXPathForNode(Node node)

Description

Does a reverse walking of the DOM tree to generate a unique XPath expression leading to this node.

License

Apache License

Parameter

Parameter	Description
node	the input node.

Return

the XPath location of node as String.

Declaration

public static String getXPathForNode(Node node) 

Method Source Code

//package com.java2s;
/*/*w  w w  . j  av  a 2 s.co  m*/
 * 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.
 */

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class Main {
    /**
     * Does a reverse walking of the DOM tree to generate a unique XPath
     * expression leading to this node. The XPath generated is the canonical
     * one based on sibling index: /html[1]/body[1]/div[2]/span[3] etc..
     *
     * @param node the input node.
     * @return the XPath location of node as String.
     */
    public static String getXPathForNode(Node node) {
        final StringBuilder sb = new StringBuilder();
        Node parent = node;
        while (parent != null && parent.getNodeType() != Node.DOCUMENT_NODE) {
            sb.insert(0, "]");
            sb.insert(0, getIndexInParent(parent) + 1);
            sb.insert(0, "[");
            sb.insert(0, parent.getNodeName());
            sb.insert(0, "/");
            parent = parent.getParentNode();
        }
        return sb.toString();
    }

    /**
     * Given a node this method returns the index corresponding to such node
     * within the list of the children of its parent node.
     *
     * @param n the node of which returning the index.
     * @return a non negative number.
     */
    public static int getIndexInParent(Node n) {
        Node parent = n.getParentNode();
        if (parent == null) {
            return 0;
        }
        NodeList nodes = parent.getChildNodes();
        int counter = -1;
        for (int i = 0; i < nodes.getLength(); i++) {
            Node current = nodes.item(i);
            if (current.getNodeType() == n.getNodeType() && current.getNodeName().equals(n.getNodeName())) {
                counter++;
            }
            if (current.equals(n)) {
                return counter;
            }
        }
        throw new IllegalStateException("Cannot find a child within its parent node list.");
    }
}

Related

1. getXPathFactory()
2. getXPathFactory()
3. getXPathFactory()
4. getXpathFilter(String xpath, Map namespaceMap)
5. getXPathForElement(Node e, NamespaceContext ctx)
6. getXPathForNode(Node node)
7. getXPathFromVector(Vector path)
8. getXPathFromVector(Vector path)
9. getXPathFromVector(Vector path)