1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 // $Id: XPathVariableResolver.java 446598 2006-09-15 12:55:40Z jeremias $ 18 19 package javax.xml.xpath; 20 21 import javax.xml.namespace.QName; 22 23 /** 24 * <p><code>XPathVariableResolver</code> provides access to the set of user defined XPath variables.</p> 25 * 26 * <p>The <code>XPathVariableResolver</code> and the XPath evaluator must adhere to a contract that 27 * cannot be directly enforced by the API. Although variables may be mutable, 28 * that is, an application may wish to evaluate the same XPath expression more 29 * than once with different variable values, in the course of evaluating any 30 * single XPath expression, a variable's value <strong><em>must</em></strong> be immutable.</p> 31 * 32 * @author <a href="mailto:Norman.Walsh (at) Sun.com">Norman Walsh</a> 33 * @author <a href="mailto:Jeff.Suttor (at) Sun.com">Jeff Suttor</a> 34 * @version $Revision: 446598 $, $Date: 2006-09-15 05:55:40 -0700 (Fri, 15 Sep 2006) $ 35 * @since 1.5 36 */ 37 public interface XPathVariableResolver { 38 /** 39 * <p>Find a variable in the set of available variables.</p> 40 * 41 * <p>If <code>variableName</code> is <code>null</code>, then a <code>NullPointerException</code> is thrown.</p> 42 * 43 * @param variableName The <code>QName</code> of the variable name. 44 * 45 * @return The variables value, or <code>null</code> if no variable named <code>variableName</code> 46 * exists. The value returned must be of a type appropriate for the underlying object model. 47 * 48 * @throws NullPointerException If <code>variableName</code> is <code>null</code>. 49 */ 50 public Object resolveVariable(QName variableName); 51 } 52
