Java XML Node Path getValueViaPath(Node node, String path)

Description

Get the value of a node specified by a starting node and a path string.

License

Open Source License

Parameter

Parameter	Description
node	the top of the tree to search.
path	the path from the top of the tree to the desired node.

Return

the value of the first node matching the path, or the empty string if no node exists at the path location or if the starting node is not an element.

Declaration

public static String getValueViaPath(Node node, String path)

Method Source Code

//package com.java2s;
/*---------------------------------------------------------------
*  Copyright 2005 by the Radiological Society of North America
*
*  This source software is released under the terms of the
*  RSNA Public License (http://mirc.rsna.org/rsnapubliclicense)
*----------------------------------------------------------------*/

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

public class Main {
    /**/*from w w  w  .ja v a 2  s.co  m*/
     * Get the value of a node specified by a starting node and a
     * path string. If the starting node is a Document, use the
     * document element as the starting point.
     * A path to an element has the form: elem1/.../elemN
     * A path to an attribute has the form: elem1/.../elemN@attr
     * The value of an element node is the sum of all the element's
     * first generation child text nodes. Note that this is not what you
     * would get from a mixed element in an XSL program.
     * @param node the top of the tree to search.
     * @param path the path from the top of the tree to the desired node.
     * @return the value of the first node matching the path, or the
     * empty string if no node exists at the path location or if the
     * starting node is not an element.
     */
    public static String getValueViaPath(Node node, String path) {
        if (node instanceof Document)
            node = ((Document) node).getDocumentElement();
        if (!(node instanceof Element))
            return "";
        path = path.trim();
        int kAtsign = path.indexOf("@");

        //If the target is an element, get the element's value.
        if (kAtsign == -1) {
            Element target = getElementViaPath(node, path);
            if (target == null)
                return "";
            return getElementValue(target);
        }

        //The target is an attribute; first find the element.
        String subpath = path.substring(0, kAtsign);
        Element target = getElementViaPath(node, subpath);
        if (target == null)
            return null;
        String name = path.substring(kAtsign + 1);
        return target.getAttribute(name);
    }

    /**
     * Get an element specified by a starting node and a path string.
     * If the starting node is a Document, use the document element
     * as the starting point.
     * A path to an element has the form: elem1/.../elemN
     * @param node the top of the tree to search.
     * @param path the path from the top of the tree to the desired element.
     * @return the first element matching the path, or null if no element
     * exists at the path location or if the starting node is not an element.
     */
    public static Element getElementViaPath(Node node, String path) {
        if (node instanceof Document)
            node = ((Document) node).getDocumentElement();
        if (!(node instanceof Element))
            return null;
        int k = path.indexOf("/");
        String firstPathElement = path;
        if (k > 0)
            firstPathElement = path.substring(0, k);
        if (node.getNodeName().equals(firstPathElement)) {
            if (k < 0)
                return (Element) node;
            path = path.substring(k + 1);
            NodeList nodeList = ((Element) node).getChildNodes();
            Node n;
            for (int i = 0; i < nodeList.getLength(); i++) {
                n = nodeList.item(i);
                if ((n instanceof Element) && ((n = getElementViaPath(n, path)) != null))
                    return (Element) n;
            }
        }
        return null;
    }

    /**
     * Get the value of an element. If the node is a Document, use the
     * document element as the element node.
     * The value of an element node is the sum of all the element's
     * first generation child text nodes. Note that this is not what you
     * would get from a mixed element in an XSL program.
     * @param node the node.
     * @return the value of the element, or an empty string if the
     * node is not an element.
     */
    public static String getElementValue(Node node) {
        if (node instanceof Document)
            node = ((Document) node).getDocumentElement();
        if (!(node instanceof Element))
            return "";
        NodeList nodeList = node.getChildNodes();
        String value = "";
        for (int i = 0; i < nodeList.getLength(); i++) {
            Node n = nodeList.item(i);
            if (n.getNodeType() == Node.TEXT_NODE)
                value += n.getNodeValue();
        }
        return value;
    }
}