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.protocol; 022 023 024 import org.apache.directory.server.dns.io.encoder.DnsMessageEncoder; 025 import org.apache.directory.server.dns.messages.DnsMessage; 026 import org.apache.mina.core.buffer.IoBuffer; 027 import org.apache.mina.core.session.IoSession; 028 import org.apache.mina.filter.codec.ProtocolEncoderAdapter; 029 import org.apache.mina.filter.codec.ProtocolEncoderOutput; 030 031 032 /** 033 * A ProtocolEncoder for use in the MINA framework that uses the 034 * DnsMessageEncoder to encode DnsMessages. 035 * 036 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 037 * @version $Rev: 545041 $, $Date: 2007-06-06 20:31:34 -0700 (Wed, 06 Jun 2007) $ 038 */ 039 public class DnsTcpEncoder extends ProtocolEncoderAdapter 040 { 041 private DnsMessageEncoder encoder = new DnsMessageEncoder(); 042 043 044 public void encode( IoSession session, Object message, ProtocolEncoderOutput out ) 045 { 046 IoBuffer buf = IoBuffer.allocate( 1024 ); 047 048 // make space for short length 049 buf.putShort( ( short ) 0 ); 050 051 encoder.encode( buf, ( DnsMessage ) message ); 052 053 // mark position 054 int end = buf.position(); 055 056 // length is the data minus 2 bytes for the pre-pended length 057 short recordLength = ( short ) ( end - 2 ); 058 059 // write the length 060 buf.rewind(); 061 buf.putShort( recordLength ); 062 063 // set the position back before flipping the buffer 064 buf.position( end ); 065 buf.flip(); 066 067 out.write( buf ); 068 } 069 }