Get the W3C Node instance associated with the XPath selection supplied : XPath « XML « Java Tutorial

Home
Java Tutorial
1.Language
2.Data Type
3.Operators
4.Statement Control
5.Class Definition
6.Development
7.Reflection
8.Regular Expressions
9.Collections
10.Thread
11.File
12.Generics
13.I18N
14.Swing
15.Swing Event
16.2D Graphics
17.SWT
18.SWT 2D Graphics
19.Network
20.Database
21.Hibernate
22.JPA
23.JSP
24.JSTL
25.Servlet
26.Web Services SOA
27.EJB3
28.Spring
29.PDF
30.Email
31.J2ME
32.J2EE Application
33.XML
34.Design Pattern
35.Log
36.Security
37.Apache Common
38.Ant
39.JUnit
Java Tutorial » XML » XPath 
33.20.2.Get the W3C Node instance associated with the XPath selection suppliedPrevious/Next
/*
 Milyn - Copyright (C) 2006

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License (version 2.1) as published by the Free Software 
 Foundation.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 
 See the GNU Lesser General Public License for more details:    
 http://www.gnu.org/licenses/lgpl.txt
 */


import org.w3c.dom.Attr;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;


import javax.xml.XMLConstants;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.FactoryConfigurationError;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;

/**
 * XMl utility methods.
 *
 @author Tom Fennelly
 */

public class XmlUtil {

    /**
     * Document validation types.
     */
    public static enum VALIDATION_TYPE {
        /**
         * No validation.
         */
        NONE,
        /**
         * DTD based validation.
         */
        DTD,
        /**
         * XSD based validation.
         */
        XSD,
    }
    private static String ELEMENT_NAME_FUNC = "/name()";

    private static XPathFactory xPathFactory = XPathFactory.newInstance();
    /**
     * Get the W3C Node instance associated with the XPath selection supplied.
     *
     @param node  The document node to be searched.
     @param xpath The XPath String to be used in the selection.
     @return The W3C Node instance at the specified location in the document,
     *         or null.
     */
    public static Node getNode(Node node, String xpath) {
        NodeList nodeList = getNodeList(node, xpath);

        if (nodeList == null || nodeList.getLength() == 0) {
            return null;
        else {
            return nodeList.item(0);
        }
    }
    /**
     * Get the W3C NodeList instance associated with the XPath selection
     * supplied.
     *
     @param node  The document node to be searched.
     @param xpath The XPath String to be used in the selection.
     @return The W3C NodeList instance at the specified location in the
     *         document, or null.
     */
    public static NodeList getNodeList(Node node, String xpath) {
        if (node == null) {
            throw new IllegalArgumentException(
                    "null 'document' arg in method call.");
        else if (xpath == null) {
            throw new IllegalArgumentException(
                    "null 'xpath' arg in method call.");
        }
        try {
            XPath xpathEvaluater = xPathFactory.newXPath();

            if (xpath.endsWith(ELEMENT_NAME_FUNC)) {
                return (NodeListxpathEvaluater.evaluate(xpath.substring(0,
                        xpath.length() - ELEMENT_NAME_FUNC.length()), node,
                        XPathConstants.NODESET);
            else {
                return (NodeListxpathEvaluater.evaluate(xpath, node,
                        XPathConstants.NODESET);
            }
        catch (XPathExpressionException e) {
            throw new IllegalArgumentException("bad 'xpath' expression ["
                    + xpath + "].");
        }
    }

}
33.20.XPath
33.20.1.Parse with XPath
33.20.2.Get the W3C Node instance associated with the XPath selection supplied
java2s.com  | Contact Us | Privacy Policy
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.