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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.mina.filter.codec.statemachine;
21  
22  import org.apache.mina.common.IoBuffer;
23  import org.apache.mina.filter.codec.ProtocolDecoderException;
24  import org.apache.mina.filter.codec.ProtocolDecoderOutput;
25  
26  /**
27   * A {@link DecodingState} which consumes all received bytes until a configured
28   * number of read bytes has been reached.  Please note that this state can
29   * produce the buffer with less data if the associated session has been
30   * closed unexpectedly.
31   *
32   * @author The Apache MINA Project (dev@mina.apache.org)
33   * @version $Rev: 601996 $, $Date: 2007-12-06 22:06:18 -0700 (Thu, 06 Dec 2007) $
34   */
35  public abstract class ConsumeToEndOfSessionDecodingState implements DecodingState {
36  
37      private IoBuffer buffer;
38      private final int maxLength;
39      
40      public ConsumeToEndOfSessionDecodingState(int maxLength) {
41          this.maxLength = maxLength;
42      }
43  
44      public DecodingState decode(IoBuffer in, ProtocolDecoderOutput out)
45              throws Exception {
46          if (buffer == null) {
47              buffer = IoBuffer.allocate(256).setAutoExpand(true);
48          }
49  
50          if (buffer.position() + in.remaining() > maxLength) {
51              throw new ProtocolDecoderException("Received data exceeds " + maxLength + " byte(s).");
52          }
53          buffer.put(in);
54          return this;
55      }
56  
57      public DecodingState finishDecode(ProtocolDecoderOutput out)
58              throws Exception {
59          try {
60              buffer.flip();
61              return finishDecode(buffer, out);
62          } finally {
63              buffer = null;
64          }
65      }
66  
67      protected abstract DecodingState finishDecode(IoBuffer readData,
68              ProtocolDecoderOutput out) throws Exception;
69  }