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1   /*
2    * Copyright 2000-2001,2004 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  
17  package org.apache.commons.jexl.util;
18  
19  
20  import java.lang.reflect.InvocationTargetException;
21  import java.lang.reflect.Method;
22  
23  import org.apache.commons.logging.Log;
24  
25  /***
26   * Abstract class that is used to execute an arbitrary
27   * method that is in introspected. This is the superclass
28   * for the GetExecutor and PropertyExecutor.
29   *
30   * @since 1.0
31   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
32   * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
33   * @version $Id: AbstractExecutor.java 398171 2006-04-29 14:57:29Z dion $
34   */
35  public abstract class AbstractExecutor {
36      /*** The executor instance log. */
37      protected Log rlog = null;
38      
39      /***
40       * Method to be executed.
41       */
42      protected Method method = null;
43      
44      /***
45       * Execute method against context.
46       *
47       * @param o The owner.
48       * @return The return value.
49       * @throws IllegalAccessException Method is inaccessible.
50       * @throws InvocationTargetException Method body throws an exception.
51       */
52       public abstract Object execute(Object o)
53           throws IllegalAccessException, InvocationTargetException;
54  
55      /***
56       * Tell whether the executor is alive by looking
57       * at the value of the method.
58       *
59       * @return boolean Whether the executor is alive.
60       */
61      public boolean isAlive() {
62          return (method != null);
63      }
64  
65      /***
66       * Get the method to be executed.
67       *
68       * @return Method The method to be executed.
69       */
70      public Method getMethod() {
71          return method;
72      }
73  }