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 package org.apache.commons.betwixt.expression; 018 019 /** <p><code>Expression</code> represents an arbitrary expression on a bean.</p> 020 * 021 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> 022 */ 023 public interface Expression { 024 025 /** Evaluates the expression on the bean with the given context 026 * and returns the result 027 * 028 * @param context evaluate against this <code>Context</code> 029 * @return the value of the expression 030 */ 031 public Object evaluate(Context context); 032 033 034 /* XXX 035 Is update actually useful? 036 None of the expression implementations i can find do anything when it's called. 037 I suspect that it's been replaced by Updater 038 but i maybe i'm missing something subtle 039 */ 040 /** <p>Updates the current bean context with a new String value. 041 * This is typically used when parsing XML and updating a beans value 042 * from XML.<p> 043 * 044 * @param context update this <code>Context</code> 045 * @param newValue the new value for this expression 046 * @deprecated 0.5 use {@link Updater} instead 047 */ 048 public void update(Context context, String newValue); 049 }