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1   /*
2    * Copyright 2002,2004 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  
17  package org.apache.commons.jexl.util.introspection;
18  
19  /***
20   * Interface used for setting values that appear to be properties in Velocity.
21   * Ex.
22   * 
23   * #set($foo.bar = "hello")
24   * 
25   * @since 1.0
26   * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
27   * @version $Id: VelPropertySet.java 398515 2006-05-01 03:46:33Z dion $
28   */
29  public interface VelPropertySet {
30      /***
31       * method used to set the value in the object.
32       * 
33       * @param o Object on which the method will be called with the arg
34       * @param arg value to be set
35       * @return the value returned from the set operation (impl specific)
36       * @throws Exception on any error.
37       */
38      Object invoke(Object o, Object arg) throws Exception;
39  
40      /***
41       * specifies if this VelPropertySet is cacheable and able to be reused for
42       * this class of object it was returned for.
43       * 
44       * @return true if can be reused for this class, false if not
45       */
46      boolean isCacheable();
47  
48      /***
49       * returns the method name used to set this 'property'.
50       * @return the method name.
51       */
52      String getMethodName();
53  }