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1   /*
2    *   @(#) $Id: TextLineDecoder.java 332218 2005-11-10 03:52:42Z trustin $
3    *
4    *   Copyright 2004 The Apache Software Foundation
5    *
6    *   Licensed under the Apache License, Version 2.0 (the "License");
7    *   you may not use this file except in compliance with the License.
8    *   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, software
13   *   distributed under the License is distributed on an "AS IS" BASIS,
14   *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   *   See the License for the specific language governing permissions and
16   *   limitations under the License.
17   *
18   */
19  package org.apache.mina.examples.reverser;
20  
21  import org.apache.mina.common.ByteBuffer;
22  import org.apache.mina.protocol.ProtocolDecoder;
23  import org.apache.mina.protocol.ProtocolDecoderOutput;
24  import org.apache.mina.protocol.ProtocolSession;
25  import org.apache.mina.protocol.ProtocolViolationException;
26  
27  /***
28   * Decodes a text line into a string.
29   * 
30   * @author The Apache Directory Project (dev@directory.apache.org)
31   * @version $Rev: 332218 $, $Date: 2005-11-10 12:52:42 +0900 $,
32   */
33  public class TextLineDecoder implements ProtocolDecoder
34  {
35  
36      private StringBuffer decodeBuf = new StringBuffer();
37  
38      public void decode( ProtocolSession session, ByteBuffer in,
39                         ProtocolDecoderOutput out )
40              throws ProtocolViolationException
41      {
42          do
43          {
44              byte b = in.get();
45              switch( b )
46              {
47              case '\r':
48                  break;
49              case '\n':
50                  String result = decodeBuf.toString();
51                  decodeBuf.delete( 0, decodeBuf.length() );
52                  out.write( result );
53                  break;
54              default:
55                  decodeBuf.append( ( char ) b );
56              }
57  
58              // Don't accept too long line
59              if( decodeBuf.length() > 256 )
60              {
61                  decodeBuf.delete( 0, decodeBuf.length() );
62                  throw new ProtocolViolationException( "The line is too long." );
63              }
64          }
65          while( in.hasRemaining() );
66      }
67  }