https://openjdk.java.net/ 
/*
 * Copyright (c) 2003, 2005, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javax.xml.xpath;

import javax.xml.namespace.QName;


XPathVariableResolver provides access to the set of user defined XPath variables.


The XPathVariableResolver 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 must
not change.


Author: Norman Walsh,  Jeff Suttor
Since:1.5
/**
 * <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>
 * @since 1.5
 */
public interface XPathVariableResolver {
  
Find a variable in the set of available variables.


If variableName is null, then a NullPointerException is thrown.


Params:
  • variableName – The QName of the variable name.
Throws:
Returns:The variables value, or null if no variable named variableName
  exists.  The value returned must be of a type appropriate for the underlying object model.
/**
   * <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);
}