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    /**
023     * This class has predefined instances that stand for OGNL's special "dynamic subscripts" for getting at the first,
024     * middle, or last elements of a list. In OGNL expressions, these subscripts look like special kinds of array indexes:
025     * [^] means the first element, [$] means the last, [|] means the middle, and [*] means the whole list.
026     * 
027     * @author Luke Blanshard (blanshlu@netscape.net)
028     * @author Drew Davidson (drew@ognl.org)
029     */
030    public class DynamicSubscript
031    {
032        public static final int FIRST = 0;
033    
034        public static final int MID = 1;
035    
036        public static final int LAST = 2;
037    
038        public static final int ALL = 3;
039    
040        public static final DynamicSubscript first = new DynamicSubscript( FIRST );
041    
042        public static final DynamicSubscript mid = new DynamicSubscript( MID );
043    
044        public static final DynamicSubscript last = new DynamicSubscript( LAST );
045    
046        public static final DynamicSubscript all = new DynamicSubscript( ALL );
047    
048        private int flag;
049    
050        private DynamicSubscript( int flag )
051        {
052            this.flag = flag;
053        }
054    
055        public int getFlag()
056        {
057            return flag;
058        }
059    
060        @Override
061        public String toString()
062        {
063            switch ( flag )
064            {
065                case FIRST:
066                    return "^";
067                case MID:
068                    return "|";
069                case LAST:
070                    return "$";
071                case ALL:
072                    return "*";
073                default:
074                    return "?"; // Won't happen
075            }
076        }
077    }