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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.demux;
    21
    22  import org.apache.mina.core.buffer.IoBuffer;
    23  import org.apache.mina.core.session.IoSession;
    24  import org.apache.mina.filter.codec.ProtocolEncoderOutput;
    25
    26  /**
    27   * Encodes a certain type of messages.
    28   * <p>
    29   * We didn't provide any <tt>dispose</tt> method for {@link MessageEncoder}
    30   * because it can give you  performance penalty in case you have a lot of
    31   * message types to handle.
    32   *
    33   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
    34   *
    35   * @see DemuxingProtocolEncoder
    36   * @see MessageEncoderFactory
    37   */
    38  public interface MessageEncoder<T> {
    39      /**
    40       * Encodes higher-level message objects into binary or protocol-specific data.
    41       * MINA invokes {@link #encode(IoSession, Object, ProtocolEncoderOutput)}
    42       * method with message which is popped from the session write queue, and then
    43       * the encoder implementation puts encoded {@link IoBuffer}s into
    44       * {@link ProtocolEncoderOutput}.
    45       *
    46       * @throws Exception if the message violated protocol specification
    47       */
    48      void encode(IoSession session, T message, ProtocolEncoderOutput out) throws Exception;
    49  }