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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *  
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *  
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License. 
18   *  
19   */
20  package org.apache.directory.server.kerberos.protocol;
21  
22  
23  import java.io.IOException;
24  
25  import org.apache.directory.server.kerberos.shared.io.encoder.ErrorMessageEncoder;
26  import org.apache.directory.server.kerberos.shared.io.encoder.KdcReplyEncoder;
27  import org.apache.directory.server.kerberos.shared.messages.ErrorMessage;
28  import org.apache.directory.server.kerberos.shared.messages.KdcReply;
29  import org.apache.mina.common.ByteBuffer;
30  import org.apache.mina.common.IoSession;
31  import org.apache.mina.filter.codec.ProtocolEncoderAdapter;
32  import org.apache.mina.filter.codec.ProtocolEncoderOutput;
33  
34  
35  /**
36   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
37   * @version $Rev$, $Date$
38   */
39  public class KerberosTcpEncoder extends ProtocolEncoderAdapter
40  {
41      private KdcReplyEncoder replyEncoder = new KdcReplyEncoder();
42      private ErrorMessageEncoder errorEncoder = new ErrorMessageEncoder();
43  
44  
45      public void encode( IoSession session, Object message, ProtocolEncoderOutput out ) throws IOException
46      {
47          ByteBuffer buf = ByteBuffer.allocate( 1024 );
48  
49          // make space for int length
50          buf.putInt( 0 );
51  
52          if ( message instanceof KdcReply )
53          {
54              replyEncoder.encode( ( KdcReply ) message, buf.buf() );
55          }
56          else
57          {
58              if ( message instanceof ErrorMessage )
59              {
60                  errorEncoder.encode( ( ErrorMessage ) message, buf.buf() );
61              }
62          }
63  
64          // mark position
65          int pos = buf.position();
66  
67          // length is the data minus 4 bytes for the pre-pended length
68          int recordLength = buf.position() - 4;
69  
70          // write the length
71          buf.rewind();
72          buf.putInt( recordLength );
73  
74          // set the position back before flipping the buffer
75          buf.position( pos );
76          buf.flip();
77  
78          out.write( buf );
79      }
80  }