protocoldecoder.java

mina是以Java实现的一个开源的网络程序框架

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 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
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 *    http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.mina.filter.codec;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;

/**
 * Decodes binary or protocol-specific data into higher-level message objects.
 * MINA invokes {@link #decode(IoSession, IoBuffer, ProtocolDecoderOutput)}
 * method with read data, and then the decoder implementation puts decoded
 * messages into {@link ProtocolDecoderOutput} by calling
 * {@link ProtocolDecoderOutput#write(Object)}.
 * <p>
 * Please refer to
 * <a href="../../../../../xref-examples/org/apache/mina/examples/reverser/TextLineDecoder.html"><code>TextLineDecoder</code></a>
 * example.
 *
 * @author The Apache MINA Project ([e-mail])
 * @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (Thu, 26 Jun 2008) $
 * 
 * @see ProtocolDecoderException
 */
public interface ProtocolDecoder {
    /**
     * Decodes binary or protocol-specific content into higher-level message objects.
     * MINA invokes {@link #decode(IoSession, IoBuffer, ProtocolDecoderOutput)}
     * method with read data, and then the decoder implementation puts decoded
     * messages into {@link ProtocolDecoderOutput}.
     *
     * @throws Exception if the read data violated protocol specification
     */
    void decode(IoSession session, IoBuffer in, ProtocolDecoderOutput out)
            throws Exception;

    /**
     * Invoked when the specified <tt>session</tt> is closed.  This method is useful
     * when you deal with the protocol which doesn't specify the length of a message
     * such as HTTP response without <tt>content-length</tt> header. Implement this
     * method to process the remaining data that {@link #decode(IoSession, IoBuffer, ProtocolDecoderOutput)}
     * method didn't process completely.
     *
     * @throws Exception if the read data violated protocol specification
     */
    void finishDecode(IoSession session, ProtocolDecoderOutput out)
            throws Exception;

    /**
     * Releases all resources related with this decoder.
     *
     * @throws Exception if failed to dispose all resources
     */
    void dispose(IoSession session) throws Exception;
}