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;
021
022import org.apache.mina.core.buffer.IoBuffer;
023import org.apache.mina.core.session.IoSession;
024
025/**
026 * Encodes higher-level message objects into binary or protocol-specific data.
027 * MINA invokes {@link #encode(IoSession, Object, ProtocolEncoderOutput)}
028 * method with message which is popped from the session write queue, and then
029 * the encoder implementation puts encoded messages (typically {@link IoBuffer}s)
030 * into {@link ProtocolEncoderOutput} by calling {@link ProtocolEncoderOutput#write(Object)}.
031 * <p>
032 * Please refer to
033 * <a href="../../../../../xref-examples/org/apache/mina/examples/reverser/TextLineEncoder.html"><code>TextLineEncoder</code></a>
034 * example.
035 *
036 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
037 * 
038 * @see ProtocolEncoderException
039 */
040public interface ProtocolEncoder {
041
042    /**
043     * Encodes higher-level message objects into binary or protocol-specific data.
044     * MINA invokes {@link #encode(IoSession, Object, ProtocolEncoderOutput)}
045     * method with message which is popped from the session write queue, and then
046     * the encoder implementation puts encoded messages (typically {@link IoBuffer}s)
047     * into {@link ProtocolEncoderOutput}.
048     *
049     * @param session The current Session
050     * @param message the message to encode
051     * @param out The {@link ProtocolEncoderOutput} that will receive the encoded message
052     * @throws Exception if the message violated protocol specification
053     */
054    void encode(IoSession session, Object message, ProtocolEncoderOutput out) throws Exception;
055
056    /**
057     * Releases all resources related with this encoder.
058     *
059     * @param session The current Session
060     * @throws Exception if failed to dispose all resources
061     */
062    void dispose(IoSession session) throws Exception;
063}