/*
 * The contents of this file are subject to the terms
 * of the Common Development and Distribution License
 * (the "License").  You may not use this file except
 * in compliance with the License.
 *
 * You can obtain a copy of the license at
 * https://jaxp.dev.java.net/CDDLv1.0.html.
 * See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL
 * HEADER in each file and include the License file at
 * https://jaxp.dev.java.net/CDDLv1.0.html
 * If applicable add the following below this CDDL HEADER
 * with the fields enclosed by brackets "[]" replaced with
 * your own identifying information: Portions Copyright
 * [year] [name of copyright owner]
 */

/*
 * $Id: XPathFactory.java,v 1.4 2005/11/03 19:34:16 jeffsuttor Exp $
 * @(#)XPathFactory.java	1.18 06/06/21
 *
 * Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
 */

package javax.xml.xpath;

/**
 * <p>An <code>XPathFactory</code> instance can be used to create
 * {@link javax.xml.xpath.XPath} objects.</p>
 *
 *<p>See {@link #newInstance(String uri)} for lookup mechanism.</p>
 *
 * <p>The {@link XPathFactory} class is not thread-safe. In other words,
 * it is the application's responsibility to ensure that at most
 * one thread is using a {@link XPathFactory} object at any
 * given moment. Implementations are encouraged to mark methods
 * as <code>synchronized</code> to protect themselves from broken clients.
 *
 * <p>{@link XPathFactory} is not re-entrant. While one of the
 * <code>newInstance</code> methods is being invoked, applications
 * may not attempt to recursively invoke a <code>newInstance</code> method,
 * even from the same thread.
 *
 * @author  <a href="mailto:Norman.Walsh@Sun.com">Norman Walsh</a>
 * @author  <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
 *
 * @version $Revision: 1.4 $, $Date: 2005/11/03 19:34:16 $
 * @since 1.5
 */
public abstract class XPathFactory {

    
    /**
     * <p>The default property name according to the JAXP spec.</p>
     */
    public static final String DEFAULT_PROPERTY_NAME = "javax.xml.xpath.XPathFactory";

    /**
     * <p>Default Object Model URI.</p>
     */
    public static final String DEFAULT_OBJECT_MODEL_URI = "http://java.sun.com/jaxp/xpath/dom";

    /**
     *<p> Take care of restrictions imposed by java security model </p>
     */    
    private static SecuritySupport ss = new SecuritySupport() ;
    
    /**
     * <p>Protected constructor as {@link #newInstance()} or {@link #newInstance(String uri)}
     * or {@link #newInstance(String uri, String factoryClassName, ClassLoader classLoader)}
     * should be used to create a new instance of an <code>XPathFactory</code>.</p>
     */
    protected XPathFactory() {
    }

    /**
     * <p>Get a new <code>XPathFactory</code> instance using the default object model,
     * {@link #DEFAULT_OBJECT_MODEL_URI},
     * the W3C DOM.</p>
     * 
     * <p>This method is functionally equivalent to:</p>
     * <pre>
     *   newInstance(DEFAULT_OBJECT_MODEL_URI)
     * </pre>
     * 
     * <p>Since the implementation for the W3C DOM is always available, this method will never fail.</p> 
     * 
     * @return Instance of an <code>XPathFactory</code>.
     *
     * @throws RuntimeException When there is a failure in creating an
     *   <code>XPathFactory</code> for the default object model.
     */
    public static final XPathFactory newInstance() {
    	
    	try {
        	return newInstance(DEFAULT_OBJECT_MODEL_URI);
    	} catch (XPathFactoryConfigurationException xpathFactoryConfigurationException) {