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.core.session.IoSession;
24 import org.apache.mina.filter.codec.ProtocolDecoderOutput;
25
26 /**
27 * Represents a state in a decoder state machine used by
28 * {@link DecodingStateMachine}.
29 *
30 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
31 */
32 public interface DecodingState {
33 /**
34 * Invoked when data is available for this state.
35 *
36 * @param in the data to be decoded.
37 * @param out used to write decoded objects.
38 * @return the next state if a state transition was triggered (use
39 * <code>this</code> for loop transitions) or <code>null</code> if
40 * the state machine has reached its end.
41 * @throws Exception if the read data violated protocol specification.
42 */
43 DecodingState decode(IoBuffer in, ProtocolDecoderOutput out) throws Exception;
44
45 /**
46 * Invoked when the associated {@link IoSession} is closed. This method is
47 * useful when you deal with protocols which don't specify the length of a
48 * message (e.g. HTTP responses without <tt>content-length</tt> header).
49 * Implement this method to process the remaining data that
50 * {@link #decode(IoBuffer, ProtocolDecoderOutput)} method didn't process
51 * completely.
52 *
53 * @param out used to write decoded objects.
54 * @return the next state if a state transition was triggered (use
55 * <code>this</code> for loop transitions) or <code>null</code> if
56 * the state machine has reached its end.
57 * @throws Exception if the read data violated protocol specification.
58 */
59 DecodingState finishDecode(ProtocolDecoderOutput out) throws Exception;
60 }