001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.mina.filter.codec.statemachine; 021 022import org.apache.mina.core.buffer.IoBuffer; 023import org.apache.mina.core.session.IoSession; 024import org.apache.mina.filter.codec.ProtocolDecoderOutput; 025 026/** 027 * Represents a state in a decoder state machine used by 028 * {@link DecodingStateMachine}. 029 * 030 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 031 */ 032public interface DecodingState { 033 /** 034 * Invoked when data is available for this state. 035 * 036 * @param in the data to be decoded. 037 * @param out used to write decoded objects. 038 * @return the next state if a state transition was triggered (use 039 * <code>this</code> for loop transitions) or <code>null</code> if 040 * the state machine has reached its end. 041 * @throws Exception if the read data violated protocol specification. 042 */ 043 DecodingState decode(IoBuffer in, ProtocolDecoderOutput out) throws Exception; 044 045 /** 046 * Invoked when the associated {@link IoSession} is closed. This method is 047 * useful when you deal with protocols which don't specify the length of a 048 * message (e.g. HTTP responses without <tt>content-length</tt> header). 049 * Implement this method to process the remaining data that 050 * {@link #decode(IoBuffer, ProtocolDecoderOutput)} method didn't process 051 * completely. 052 * 053 * @param out used to write decoded objects. 054 * @return the next state if a state transition was triggered (use 055 * <code>this</code> for loop transitions) or <code>null</code> if 056 * the state machine has reached its end. 057 * @throws Exception if the read data violated protocol specification. 058 */ 059 DecodingState finishDecode(ProtocolDecoderOutput out) throws Exception; 060}