001    package org.apache.commons.ognl;
002    
003    /*
004     * Licensed to the Apache Software Foundation (ASF) under one
005     * or more contributor license agreements.  See the NOTICE file
006     * distributed with this work for additional information
007     * regarding copyright ownership.  The ASF licenses this file
008     * to you under the Apache License, Version 2.0 (the
009     * "License"); you may not use this file except in compliance
010     * with the License.  You may obtain a copy of the License at
011     *
012     *   http://www.apache.org/licenses/LICENSE-2.0
013     *
014     * Unless required by applicable law or agreed to in writing,
015     * software distributed under the License is distributed on an
016     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017     * KIND, either express or implied.  See the License for the
018     * specific language governing permissions and limitations
019     * under the License.
020     */
021    
022    import java.util.Enumeration;
023    import java.util.Map;
024    
025    /**
026     * Implementation of PropertyAccessor that provides "property" reference to "nextElement" (aliases to "next" also) and
027     * "hasMoreElements" (also aliased to "hasNext").
028     * 
029     * @author Luke Blanshard (blanshlu@netscape.net)
030     * @author Drew Davidson (drew@ognl.org)
031     */
032    public class EnumerationPropertyAccessor
033        extends ObjectPropertyAccessor
034        implements PropertyAccessor // This is here to make javadoc show this class as an implementor
035    {
036        @Override
037        public Object getProperty( Map<String, Object> context, Object target, Object name )
038            throws OgnlException
039        {
040            Object result;
041            Enumeration<?> e = (Enumeration<?>) target; // check performed by the invoker
042    
043            if ( name instanceof String )
044            {
045                if ( "next".equals( name ) || "nextElement".equals( name ) )
046                {
047                    result = e.nextElement();
048                }
049                else
050                {
051                    if ( "hasNext".equals( name ) || "hasMoreElements".equals( name ) )
052                    {
053                        result = e.hasMoreElements() ? Boolean.TRUE : Boolean.FALSE;
054                    }
055                    else
056                    {
057                        result = super.getProperty( context, target, name );
058                    }
059                }
060            }
061            else
062            {
063                result = super.getProperty( context, target, name );
064            }
065            return result;
066        }
067    
068        @Override
069        public void setProperty( Map<String, Object> context, Object target, Object name, Object value )
070            throws OgnlException
071        {
072            throw new IllegalArgumentException( "can't set property " + name + " on Enumeration" );
073        }
074    }