/*
* 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: XMLEntityReader.java,v 1.3 2005/11/03 17:02:21 jeffsuttor Exp $
* @(#)XPathVariableResolver.java 1.13 05/11/17
*
* Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
*/
package javax.xml.xpath;
import javax.xml.namespace.QName;
/**
* <p><code>XPathVariableResolver</code> provides access to the set of user defined XPath variables.</p>
*
* <p>The <code>XPathVariableResolver</code> and the XPath evaluator must adhere to a contract that
* cannot be directly enforced by the API. Although variables may be mutable,
* that is, an application may wish to evaluate the same XPath expression more
* than once with different variable values, in the course of evaluating any
* single XPath expression, a variable's value <strong><em>must</em></strong>
* not change.</p>
*
* @author <a href="mailto:Norman.Walsh@Sun.com">Norman Walsh</a>
* @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
* @version $Revision: 1.3 $, $Date: 2005/07/25 14:46:33 $
* @since 1.5
*/
public interface XPathVariableResolver {
/**
* <p>Find a variable in the set of available variables.</p>
*
* <p>If <code>variableName</code> is <code>null</code>, then a <code>NullPointerException</code> is thrown.</p>
*
* @param variableName The <code>QName</code> of the variable name.
*
* @return The variables value, or <code>null</code> if no variable named <code>variableName</code>
* exists. The value returned must be of a type appropriate for the underlying object model.
*
* @throws NullPointerException If <code>variableName</code> is <code>null</code>.
*/
public Object resolveVariable(QName variableName);
}