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    
021    package org.apache.directory.server.dns.io.decoder;
022    
023    
024    import java.io.IOException;
025    import java.util.HashMap;
026    import java.util.Map;
027    
028    import org.apache.directory.server.dns.store.DnsAttribute;
029    import org.apache.mina.core.buffer.IoBuffer;
030    
031    
032    /**
033     * A decoder for MX records.  MX records are encoded as per RFC-1035:
034     * 
035     * <pre>
036     *   3.3.9. MX RDATA format
037     *
038     *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
039     *     |                  PREFERENCE                   |
040     *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
041     *     /                   EXCHANGE                    /
042     *     /                                               /
043     *     +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
044     *
045     *   where:
046     *
047     *   PREFERENCE
048     *     A 16 bit integer which specifies the preference given to this RR among 
049     *     others at the same owner. Lower values are preferred. 
050     *     
051     *   EXCHANGE
052     *     A <domain-name> which specifies a host willing to act as a mail exchange
053     *     for the owner name.
054     * </pre>
055     * 
056     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
057     * @version $Rev$, $Date$
058     */
059    public class MailExchangeRecordDecoder implements RecordDecoder
060    {
061        public Map<String, Object> decode( IoBuffer byteBuffer, short length ) throws IOException
062        {
063            Map<String, Object> attributes = new HashMap<String, Object>();
064            attributes.put( DnsAttribute.MX_PREFERENCE, byteBuffer.getShort() );
065            attributes.put( DnsAttribute.DOMAIN_NAME, DnsMessageDecoder.getDomainName( byteBuffer ) );
066            return attributes;
067        }
068    }