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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  import java.lang.reflect.InvocationTargetException;
20  
21  import org.apache.commons.logging.Log;
22  
23  
24  /***
25   * Executor that simply tries to execute a get(key)
26   * operation. This will try to find a get(key) method
27   * for any type of object, not just objects that
28   * implement the Map interface as was previously
29   * the case.
30   *
31   * @since 1.0
32   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
33   * @version $Id: GetExecutor.java 398171 2006-04-29 14:57:29Z dion $
34   */
35  public class GetExecutor extends AbstractExecutor {
36      /***
37       * Container to hold the 'key' part of 
38       * get(key).
39       */
40      private final Object[] args = new Object[1];
41      
42      /***
43       * Default constructor.
44       *
45       * @param r The instance log.
46       * @param ispect The JEXL introspector.
47       * @param c The class being examined.
48       * @param key The key for the get(key) operation.
49       * @throws Exception Failure while trying to obtain the pertinent method.
50       */
51      public GetExecutor(Log r,
52              org.apache.commons.jexl.util.introspection.Introspector ispect,
53              Class c, String key) throws Exception {
54          rlog = r;
55          args[0] = key;
56          method = ispect.getMethod(c, "get", args);
57      }
58  
59      /***
60       * {@inheritDoc}
61       */
62      public Object execute(Object o)
63      throws IllegalAccessException, InvocationTargetException {
64          if (method == null) {
65              return null;
66          }
67  
68          return method.invoke(o, args);
69      }
70  
71  }
72