Java XPath Evaluate evalXPath(Node d, String expr, QName returnType)

Description

Gets the object at the given XPath in the given XML node.

License

Apache License

Parameter

Parameter	Description
d	the node to look in
expr	the XPath expression to evaluate
returnType	the expected return type of the object

Exception

Parameter	Description
XPathExpressionException	if an error occurs processing the XPathexpression

Return

the object at the specified XPath in the node

Declaration

static Object evalXPath(Node d, String expr, QName returnType) throws XPathExpressionException 

Method Source Code

//package com.java2s;
/*//from   w  w  w .  j av a 2  s.c  o m
 * #%L
 * i2b2 Export Service
 * %%
 * Copyright (C) 2013 Emory University
 * %%
 * Licensed 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.
 * #L%
 */

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import javax.xml.namespace.QName;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import java.io.IOException;
import java.io.StringReader;

public class Main {
    /**
     * Gets the object at the given XPath in the given XML node. See also:
     * {@link #evalXPath(String, String, javax.xml.namespace.QName)}.
     *
     * @param d the node to look in
     * @param expr the XPath expression to evaluate
     * @param returnType the expected return type of the object
     * @return the object at the specified XPath in the node
     * @throws XPathExpressionException if an error occurs processing the XPath
     * expression
     */
    static Object evalXPath(Node d, String expr, QName returnType) throws XPathExpressionException {
        return XPathFactory.newInstance().newXPath().compile(expr).evaluate(d, returnType);
    }

    /**
     * Gets the object at the given XPath in the given XML string. See also:
     * {@link #evalXPath(org.w3c.dom.Node, String, javax.xml.namespace.QName)}.
     *
     * @param xml the XML string to look in
     * @param expr the XPath expression to evaluate
     * @param returnType expected return type of the object
     * @return the object at the specified XPath in the XML string
     * @throws XPathExpressionException if an error occurs while processing the
     * XPath expression
     * @throws SAXException if an error occurs converting the XML string to an
     * XML node
     * @throws IOException if a general IO error occurs
     * @throws ParserConfigurationException if an error occurs configuring the
     * parser
     */
    static Object evalXPath(String xml, String expr, QName returnType)
            throws XPathExpressionException, SAXException, IOException, ParserConfigurationException {
        return evalXPath(xmlStringToDocument(xml), expr, returnType);
    }

    /**
     * Converts an XML string into an equivalent XML document. Applies the
     * reverse operation of {@link #xmlDocumentToString(org.w3c.dom.Node)}.
     *
     * @param xml the XML string to convert
     * @return a {@link Document} equivalent to the specified XML string
     * @throws SAXException if an error occurs building the XML document
     * @throws IOException if a general IO error occurs
     * @throws ParserConfigurationException if an error occurs configuring the
     * XML parser
     */
    static Document xmlStringToDocument(String xml) throws SAXException, IOException, ParserConfigurationException {
        return DocumentBuilderFactory.newInstance().newDocumentBuilder()
                .parse(new InputSource(new StringReader(xml)));
    }
}

Related

1. evaluateXPathExpr(XPathExpression xpath, Node node)
2. evaluateXPathExpression(final String expression, final Node node)
3. evaluateXPathExpressionAndReturnNode(String expression, Node node)
4. evaluateXPathExpressionAndReturnNodeList(String expression, Node node)
5. evaluateXPathQuery(Document doc, NamespaceContext context, String xPathQuery)
6. evalXPath(Node node, String xPath)
7. evalXPath(String expression, Object item, Class type)
8. evalXPath(String path, Document doc)
9. evalXpath(String xpath, Object item)