1   /**
2    * Logback: the reliable, generic, fast and flexible logging framework.
3    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
4    *
5    * This program and the accompanying materials are dual-licensed under
6    * either the terms of the Eclipse Public License v1.0 as published by
7    * the Eclipse Foundation
8    *
9    *   or (per the licensee's choosing)
10   *
11   * under the terms of the GNU Lesser General Public License version 2.1
12   * as published by the Free Software Foundation.
13   */
14  package ch.qos.logback.core.net.server;
15  
16  import java.io.Closeable;
17  import java.io.IOException;
18  
19  /**
20   * A client of a {@link ServerRunner}.
21   * <p>
22   * This interface exists primarily to abstract away the details of the client's
23   * underlying {@code Socket} and the concurrency associated with handling
24   * multiple clients. Such realities make it difficult to create effective unit
25   * tests for the {@link ServerRunner} that are easy to understand and maintain.
26   * <p>
27   * This interface captures the only those details about a client that the
28   * {@code ServerRunner} cares about; namely, that it is something that
29   * <ol>
30   * <li>is Runnable &mdash; i.e. it can be executed concurrently</li>
31   * <li>holds resources that need to be closed before the client is
32   * discarded</li>
33   * </ol>
34   * 
35   * @author Carl Harris
36   */
37  public interface Client extends Runnable, Closeable {
38  
39      /**
40       * Closes any resources that are held by the client.
41       * <p>
42       * Note that (as described in Doug Lea's discussion about interrupting I/O
43       * operations in "Concurrent Programming in Java" - Addison-Wesley Professional,
44       * 2nd edition, 1999) this method is used to interrupt any blocked I/O operation
45       * in the client when the server is shutting down. The client implementation
46       * must anticipate this potential, and gracefully exit when the blocked I/O
47       * operation throws the relevant {@link IOException} subclass.
48       * <p>
49       * Note also, that unlike {@link Closeable#close()} this method is not permitted
50       * to propagate any {@link IOException} that occurs when closing the underlying
51       * resource(s).
52       */
53      void close();
54  
55  }