01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * 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: package org.apache.commons.betwixt.expression;
18:
19: /** <p><code>Expression</code> represents an arbitrary expression on a bean.</p>
20: *
21: * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
22: */
23: public interface Expression {
24:
25: /** Evaluates the expression on the bean with the given context
26: * and returns the result
27: *
28: * @param context evaluate against this <code>Context</code>
29: * @return the value of the expression
30: */
31: public Object evaluate(Context context);
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36: I suspect that it's been replaced by Updater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: }
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