001    /*
002    * Licensed to the Apache Software Foundation (ASF) under one or more
003    * contributor license agreements.  See the NOTICE file distributed with
004    * this work for additional information regarding copyright ownership.
005    * The ASF licenses this file to You under the Apache License, Version 2.0
006    * (the "License"); you may not use this file except in compliance with
007    * the License.  You may obtain a copy of the License at
008    *
009    *     http://www.apache.org/licenses/LICENSE-2.0
010    *
011    * Unless required by applicable law or agreed to in writing, software
012    * distributed under the License is distributed on an "AS IS" BASIS,
013    * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014    * See the License for the specific language governing permissions and
015    * limitations under the License.
016    */
017    
018    package javax.servlet.jsp.el;
019    
020    /**
021     * <p>This class is used to customize the way an ExpressionEvaluator resolves
022     * variable references at evaluation time.  For example, instances of this class can
023     * implement their own variable lookup mechanisms, or introduce the
024     * notion of "implicit variables" which override any other variables.
025     * An instance of this class should be passed when evaluating
026     * an expression.</p>
027     *
028     * <p>An instance of this class includes the context against which resolution
029     * will happen</p>
030     *
031     * @since 2.0
032     * @deprecated
033     */
034    public interface VariableResolver
035    {
036      //-------------------------------------
037      /**
038       * Resolves the specified variable.
039       * Returns null if the variable is not found.
040       * 
041       * @param pName the name of the variable to resolve
042       * @return the result of the variable resolution
043       *
044       * @throws ELException if a failure occurred while trying to resolve
045       *     the given variable
046       **/
047      public Object resolveVariable (String pName)
048        throws ELException;
049                                            
050      //-------------------------------------
051    }