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