001    /*
002     *  Licensed to the Apache Software Foundation (ASF) under one
003     *  or more contributor license agreements.  See the NOTICE file
004     *  distributed with this work for additional information
005     *  regarding copyright ownership.  The ASF licenses this file
006     *  to you under the Apache License, Version 2.0 (the
007     *  "License"); you may not use this file except in compliance
008     *  with the License.  You may obtain a copy of the License at
009     *  
010     *    http://www.apache.org/licenses/LICENSE-2.0
011     *  
012     *  Unless required by applicable law or agreed to in writing,
013     *  software distributed under the License is distributed on an
014     *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     *  KIND, either express or implied.  See the License for the
016     *  specific language governing permissions and limitations
017     *  under the License. 
018     *  
019     */
020    package org.apache.directory.server.core.partition.impl.btree.jdbm;
021    
022    
023    import java.io.IOException;
024    
025    import jdbm.helper.Serializer;
026    
027    
028    /**
029     * A custom String serializer to [de]serialize Strings.
030     *
031     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
032     * @version $Rev$, $Date$
033     */
034    public class StringSerializer implements Serializer
035    {
036        private static final long serialVersionUID = -173163945773783649L;
037    
038    
039        /* (non-Javadoc)
040         * @see jdbm.helper.Serializer#deserialize(byte[])
041         */
042        public Object deserialize( byte[] bites ) throws IOException
043        {
044            if ( bites.length == 0 )
045            {
046                return "";
047            }
048    
049            char[] strchars = new char[bites.length >> 1];
050            for ( int ii = 0, jj = 0; ii < strchars.length; ii++, jj = ii << 1 )
051            {
052                int ch = bites[jj] << 8 & 0x0000FF00;
053                ch |= bites[jj+1] & 0x000000FF;
054                strchars[ii] = ( char ) ch;
055            }
056            return new String( strchars );
057        }
058    
059    
060        private static final byte[] EMPTY_BYTE_ARRAY = new byte[0];
061        
062        /* (non-Javadoc)
063         * @see jdbm.helper.Serializer#serialize(java.lang.Object)
064         */
065        public byte[] serialize( Object str ) throws IOException
066        {
067            if ( ( ( String ) str ).length() == 0 )
068            {
069                return EMPTY_BYTE_ARRAY;
070            }
071            
072            char[] strchars = ( ( String ) str ).toCharArray();
073            byte[] bites = new byte[strchars.length<<1];
074            for ( int ii = 0, jj = 0; ii < strchars.length; ii++, jj = ii << 1 )
075            {
076                bites[jj] = ( byte ) ( strchars[ii] >> 8 & 0x00FF );
077                bites[jj+1] = ( byte ) ( strchars[ii] & 0x00FF );
078            }
079            
080            return bites;
081        }
082    }