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1   package org.apache.commons.ognl;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import java.util.Enumeration;
23  import java.util.Map;
24  
25  /**
26   * Implementation of PropertyAccessor that provides "property" reference to "nextElement" (aliases to "next" also) and
27   * "hasMoreElements" (also aliased to "hasNext").
28   * 
29   * @author Luke Blanshard (blanshlu@netscape.net)
30   * @author Drew Davidson (drew@ognl.org)
31   */
32  public class EnumerationPropertyAccessor
33      extends ObjectPropertyAccessor
34      implements PropertyAccessor // This is here to make javadoc show this class as an implementor
35  {
36      @Override
37      public Object getProperty( Map<String, Object> context, Object target, Object name )
38          throws OgnlException
39      {
40          Object result;
41          Enumeration<?> e = (Enumeration<?>) target; // check performed by the invoker
42  
43          if ( name instanceof String )
44          {
45              if ( "next".equals( name ) || "nextElement".equals( name ) )
46              {
47                  result = e.nextElement();
48              }
49              else
50              {
51                  if ( "hasNext".equals( name ) || "hasMoreElements".equals( name ) )
52                  {
53                      result = e.hasMoreElements() ? Boolean.TRUE : Boolean.FALSE;
54                  }
55                  else
56                  {
57                      result = super.getProperty( context, target, name );
58                  }
59              }
60          }
61          else
62          {
63              result = super.getProperty( context, target, name );
64          }
65          return result;
66      }
67  
68      @Override
69      public void setProperty( Map<String, Object> context, Object target, Object name, Object value )
70          throws OgnlException
71      {
72          throw new IllegalArgumentException( "can't set property " + name + " on Enumeration" );
73      }
74  }