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    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;
    21
    22  import org.apache.mina.common.ByteBuffer;
    23  import org.apache.mina.common.IoSession;
    24
    25  /**
    26   * Decodes binary or protocol-specific data into higher-level message objects.
    27   * MINA invokes {@link #decode(IoSession, ByteBuffer, ProtocolDecoderOutput)}
    28   * method with read data, and then the decoder implementation puts decoded
    29   * messages into {@link ProtocolDecoderOutput} by calling
    30   * {@link ProtocolDecoderOutput#write(Object)}.
    31   * <p>
    32   * Please refer to
    33   * <a href="../../../../../xref-examples/org/apache/mina/examples/reverser/TextLineDecoder.html"><code>TextLineDecoder</code></a>
    34   * example.
    35   *
    36   * @author The Apache Directory Project (mina-dev@directory.apache.org)
    37   * @version $Rev: 555855 $, $Date: 2007-07-13 05:19:00 +0200 (Fri, 13 Jul 2007) $
    38   */
    39  public interface ProtocolDecoder {
    40      /**
    41       * Decodes binary or protocol-specific content into higher-level message objects.
    42       * MINA invokes {@link #decode(IoSession, ByteBuffer, ProtocolDecoderOutput)}
    43       * method with read data, and then the decoder implementation puts decoded
    44       * messages into {@link ProtocolDecoderOutput}.
    45       *
    46       * @throws Exception if the read data violated protocol specification
    47       */
    48      void decode(IoSession session, ByteBuffer in, ProtocolDecoderOutput out)
    49              throws Exception;
    50
    51      /**
    52       * Invoked when the specified <tt>session</tt> is closed.  This method is useful
    53       * when you deal with the protocol which doesn't specify the length of a message
    54       * such as HTTP response without <tt>content-length</tt> header. Implement this
    55       * method to process the remaining data that {@link #decode(IoSession, ByteBuffer, ProtocolDecoderOutput)}
    56       * method didn't process completely.
    57       *
    58       * @throws Exception if the read data violated protocol specification
    59       */
    60      void finishDecode(IoSession session, ProtocolDecoderOutput out)
    61              throws Exception;
    62
    63      /**
    64       * Releases all resources related with this decoder.
    65       *
    66       * @throws Exception if failed to dispose all resources
    67       */
    68      void dispose(IoSession session) throws Exception;
    69  }