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
21 package org.apache.directory.server.dns.protocol;
22
23
24 import org.apache.directory.server.dns.io.encoder.DnsMessageEncoder;
25 import org.apache.directory.server.dns.messages.DnsMessage;
26 import org.apache.mina.core.buffer.IoBuffer;
27 import org.apache.mina.core.session.IoSession;
28 import org.apache.mina.filter.codec.ProtocolEncoderAdapter;
29 import org.apache.mina.filter.codec.ProtocolEncoderOutput;
30
31
32 /**
33 * A ProtocolEncoder for use in the MINA framework that uses the
34 * DnsMessageEncoder to encode DnsMessages.
35 *
36 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
37 */
38 public class DnsTcpEncoder extends ProtocolEncoderAdapter
39 {
40 private DnsMessageEncoder/encoder/DnsMessageEncoder.html#DnsMessageEncoder">DnsMessageEncoder encoder = new DnsMessageEncoder();
41
42
43 public void encode( IoSession session, Object message, ProtocolEncoderOutput out )
44 {
45 IoBuffer buf = IoBuffer.allocate( 1024 );
46
47 // make space for short length
48 buf.putShort( ( short ) 0 );
49
50 encoder.encode( buf, ( DnsMessage ) message );
51
52 // mark position
53 int end = buf.position();
54
55 // length is the data minus 2 bytes for the pre-pended length
56 short recordLength = ( short ) ( end - 2 );
57
58 // write the length
59 buf.rewind();
60 buf.putShort( recordLength );
61
62 // set the position back before flipping the buffer
63 buf.position( end );
64 buf.flip();
65
66 out.write( buf );
67 }
68 }