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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  }