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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 org.apache.commons.logging.Log;
20  /***
21   *  Handles discovery and valuation of a
22   *  boolean object property, of the
23   *  form public boolean is<property> when executed.
24   *
25   *  We do this separately as to preserve the current
26   *  quasi-broken semantics of get<as is property>
27   *  get< flip 1st char> get("property") and now followed
28   *  by is<Property>
29   *
30   *  @author <a href="geirm@apache.org">Geir Magnusson Jr.</a>
31   *  @version $Id: BooleanPropertyExecutor.java,v 1.4 2004/02/28 13:45:21 yoavs Exp $
32   */
33  public class BooleanPropertyExecutor extends PropertyExecutor
34  {
35      public BooleanPropertyExecutor(Log rlog, org.apache.commons.jexl.util.introspection.Introspector is, Class clazz, String property)
36      {
37          super(rlog, is, clazz, property);
38      }
39  
40      protected void discover(Class clazz, String property)
41      {
42          try
43          {
44              char c;
45              StringBuffer sb;
46  
47              Object[] params = {  };
48  
49              /*
50               *  now look for a boolean isFoo
51               */
52  
53              sb = new StringBuffer("is");
54              sb.append(property);
55  
56              c = sb.charAt(2);
57  
58              if (Character.isLowerCase(c))
59              {
60                  sb.setCharAt(2, Character.toUpperCase(c));
61              }
62  
63              methodUsed = sb.toString();
64              method = introspector.getMethod(clazz, methodUsed, params);
65  
66              if (method != null)
67              {
68                  /*
69                   *  now, this has to return a boolean
70                   */
71  
72                  if (method.getReturnType() == Boolean.TYPE)
73                      return;
74  
75                  method = null;
76              }
77          }
78          catch(Exception e)
79          {
80              rlog.error("PROGRAMMER ERROR : BooleanPropertyExector() : " + e);
81          }
82      }
83  }