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.core.buffer.IoBuffer;
23 import org.apache.mina.filter.codec.ProtocolDecoderException;
24 import org.apache.mina.filter.codec.ProtocolDecoderOutput;
25
26 /**
27 * {@link DecodingState} which consumes all received bytes until the session is
28 * closed.
29 *
30 * @author The Apache MINA Project (dev@mina.apache.org)
31 * @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (jeu, 26 jun 2008) $
32 */
33 public abstract class ConsumeToEndOfSessionDecodingState implements DecodingState {
34
35 private IoBuffer buffer;
36 private final int maxLength;
37
38 /**
39 * Creates a new instance using the specified maximum length.
40 *
41 * @param maxLength the maximum number of bytes which will be consumed. If
42 * this max is reached a {@link ProtocolDecoderException} will be
43 * thrown by {@link #decode(IoBuffer, ProtocolDecoderOutput)}.
44 */
45 public ConsumeToEndOfSessionDecodingState(int maxLength) {
46 this.maxLength = maxLength;
47 }
48
49 /**
50 * {@inheritDoc}
51 */
52 public DecodingState decode(IoBuffer in, ProtocolDecoderOutput out)
53 throws Exception {
54 if (buffer == null) {
55 buffer = IoBuffer.allocate(256).setAutoExpand(true);
56 }
57
58 if (buffer.position() + in.remaining() > maxLength) {
59 throw new ProtocolDecoderException("Received data exceeds " + maxLength + " byte(s).");
60 }
61 buffer.put(in);
62 return this;
63 }
64
65 /**
66 * {@inheritDoc}
67 */
68 public DecodingState finishDecode(ProtocolDecoderOutput out)
69 throws Exception {
70 try {
71 if (buffer == null) {
72 buffer = IoBuffer.allocate(0);
73 }
74 buffer.flip();
75 return finishDecode(buffer, out);
76 } finally {
77 buffer = null;
78 }
79 }
80
81 /**
82 * Invoked when this state has consumed all bytes until the session is
83 * closed.
84 *
85 * @param product the bytes read.
86 * @param out the current {@link ProtocolDecoderOutput} used to write
87 * decoded messages.
88 * @return the next state if a state transition was triggered (use
89 * <code>this</code> for loop transitions) or <code>null</code> if
90 * the state machine has reached its end.
91 * @throws Exception if the read data violated protocol specification.
92 */
93 protected abstract DecodingState finishDecode(IoBuffer product,
94 ProtocolDecoderOutput out) throws Exception;
95 }