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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.core.service;
21  
22  import java.io.IOException;
23  
24  import org.apache.mina.core.session.IdleStatus;
25  import org.apache.mina.core.session.IoSession;
26  
27  /**
28   * Handles all I/O events fired by MINA.
29   *
30   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
31   *
32   * @see IoHandlerAdapter
33   */
34  public interface IoHandler {
35      /**
36       * Invoked from an I/O processor thread when a new connection has been created.
37       * Because this method is supposed to be called from the same thread that
38       * handles I/O of multiple sessions, please implement this method to perform
39       * tasks that consumes minimal amount of time such as socket parameter
40       * and user-defined session attribute initialization.
41       */
42      void sessionCreated(IoSession session) throws Exception;
43  
44      /**
45       * Invoked when a connection has been opened.  This method is invoked after
46       * {@link #sessionCreated(IoSession)}.  The biggest difference from
47       * {@link #sessionCreated(IoSession)} is that it's invoked from other thread
48       * than an I/O processor thread once thread model is configured properly.
49       */
50      void sessionOpened(IoSession session) throws Exception;
51  
52      /**
53       * Invoked when a connection is closed.
54       */
55      void sessionClosed(IoSession session) throws Exception;
56  
57      /**
58       * Invoked with the related {@link IdleStatus} when a connection becomes idle.
59       * This method is not invoked if the transport type is UDP; it's a known bug,
60       * and will be fixed in 2.0.
61       */
62      void sessionIdle(IoSession session, IdleStatus status) throws Exception;
63  
64      /**
65       * Invoked when any exception is thrown by user {@link IoHandler}
66       * implementation or by MINA.  If <code>cause</code> is an instance of
67       * {@link IOException}, MINA will close the connection automatically.
68       */
69      void exceptionCaught(IoSession session, Throwable cause) throws Exception;
70  
71      /**
72       * Invoked when a message is received.
73       */
74      void messageReceived(IoSession session, Object message) throws Exception;
75  
76      /**
77       * Invoked when a message written by {@link IoSession#write(Object)} is
78       * sent out.
79       */
80      void messageSent(IoSession session, Object message) throws Exception;
81  
82      /**
83       * Handle the closure of an half-duplex TCP channel
84       */
85      void inputClosed(IoSession session) throws Exception;
86  }