1 /*
2 * Copyright 2001-2004 The Apache Software Foundation.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.apache.commons.betwixt.expression;
17
18 /*** <p><code>Expression</code> represents an arbitrary expression on a bean.</p>
19 *
20 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
21 */
22 public interface Expression {
23
24 /*** Evaluates the expression on the bean with the given context
25 * and returns the result
26 *
27 * @param context evaluate against this <code>Context</code>
28 * @return the value of the expression
29 */
30 public Object evaluate(Context context);
31
32
33 /* XXX
34 Is update actually useful?
35 None of the expression implementations i can find do anything when it's called.
36 I suspect that it's been replaced by Updater
37 but i maybe i'm missing something subtle
38 */
39 /*** <p>Updates the current bean context with a new String value.
40 * This is typically used when parsing XML and updating a beans value
41 * from XML.<p>
42 *
43 * @param context update this <code>Context</code>
44 * @param newValue the new value for this expression
45 * @deprecated 0.5 use {@link Updater} instead
46 */
47 public void update(Context context, String newValue);
48 }