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.demux; 021 022import org.apache.mina.core.buffer.IoBuffer; 023import org.apache.mina.core.session.IoSession; 024import org.apache.mina.filter.codec.ProtocolEncoderOutput; 025 026/** 027 * Encodes a certain type of messages. 028 * <p> 029 * We didn't provide any <tt>dispose</tt> method for {@link MessageEncoder} 030 * because it can give you performance penalty in case you have a lot of 031 * message types to handle. 032 * 033 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 034 * 035 * @see DemuxingProtocolEncoder 036 * @see MessageEncoderFactory 037 * 038 * @param T The message type 039 */ 040public interface MessageEncoder<T> { 041 /** 042 * Encodes higher-level message objects into binary or protocol-specific data. 043 * MINA invokes {@link #encode(IoSession, Object, ProtocolEncoderOutput)} 044 * method with message which is popped from the session write queue, and then 045 * the encoder implementation puts encoded {@link IoBuffer}s into 046 * {@link ProtocolEncoderOutput}. 047 * 048 * @param session The current session 049 * @param message The message to encode 050 * @param out The instance of {@link ProtocolEncoderOutput} that will receive the encoded message 051 * @throws Exception if the message violated protocol specification 052 */ 053 void encode(IoSession session, T message, ProtocolEncoderOutput out) throws Exception; 054}