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
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) 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) throws Exception {
68 try {
69 if (buffer == null) {
70 buffer = IoBuffer.allocate(0);
71 }
72 buffer.flip();
73 return finishDecode(buffer, out);
74 } finally {
75 buffer = null;
76 }
77 }
78
79 /**
80 * Invoked when this state has consumed all bytes until the session is
81 * closed.
82 *
83 * @param product the bytes read.
84 * @param out the current {@link ProtocolDecoderOutput} used to write
85 * decoded messages.
86 * @return the next state if a state transition was triggered (use
87 * <code>this</code> for loop transitions) or <code>null</code> if
88 * the state machine has reached its end.
89 * @throws Exception if the read data violated protocol specification.
90 */
91 protected abstract DecodingState finishDecode(IoBuffer product, ProtocolDecoderOutput out) throws Exception;
92 }