Java XPath Create xpath(String expression)

Description

Builds an XPath.

License

Open Source License

Parameter

Parameter	Description
expression	The XPath expression to compile.

Exception

Parameter	Description
AssertionError	If the nested call to <tt>XPath.newInstance(path)</tt>throws an XPathExpressionException.

Declaration

public static synchronized XPathExpression xpath(String expression) 

Method Source Code

//package com.java2s;
/**/*w  w w .  ja v  a  2s  .  com*/
 * This file is protected by Copyright. Please refer to the COPYRIGHT file
 * distributed with this source distribution.
 *
 * This file is part of REDHAWK.
 *
 * REDHAWK is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * REDHAWK 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.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see http://www.gnu.org/licenses/.
 */

import javax.xml.xpath.XPath;

import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

public class Main {
    private static XPath xPath = null;

    /** Builds an XPath. This is identical to calling
     *  <tt>XPathFactory.newInstance().newXPath().compile(expression)</tt> except
     *  that rather than throwing an {@link XPathExpressionException} it throws an
     *  {@link AssertionError}. <br>
     *  <br>
     *  This is intended for use with pre-defined XPaths stored as constants,
     *  where runtime exceptions should not be possible.
     *  @param expression The XPath expression to compile.
     *  @throws AssertionError If the nested call to <tt>XPath.newInstance(path)</tt>
     *                         throws an {@link XPathExpressionException}.
     */
    public static synchronized XPathExpression xpath(String expression) {
        if (xPath == null)
            xPath = XPathFactory.newInstance().newXPath();

        try {
            return xPath.compile(expression);
        } catch (XPathExpressionException e) {
            throw new AssertionError("Error initializing XPath instance for '" + expression + "': " + e);
        }
    }
}

Related

1. newXPath()
2. newXpathExpression(final XPath xpath, final String expression)
3. newXPathFactory()
4. xPath()
5. xpath()
6. xpath(String xml, String xpath)
7. xPath(String xPath)
8. xpathNode(Node node, String xpath)
9. xpathNodes(Node node, String expression)