1 /*
2  * Copyright (c) 2011 Oracle and/or its affiliates. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  *   - Redistributions of source code must retain the above copyright
9  *     notice, this list of conditions and the following disclaimer.
10  *
11  *   - Redistributions in binary form must reproduce the above copyright
12  *     notice, this list of conditions and the following disclaimer in the
13  *     documentation and/or other materials provided with the distribution.
14  *
15  *   - Neither the name of Oracle nor the names of its
16  *     contributors may be used to endorse or promote products derived
17  *     from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
20  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * This source code is provided to illustrate the usage of a given feature
34  * or technique and has been deliberately simplified. Additional steps
35  * required for a production-quality application, such as security checks,
36  * input validation and proper error handling, might not be present in
37  * this sample code.
38  */
39 
40 
41 import java.nio.ByteBuffer;
42 import java.nio.channels.CompletionHandler;
43 
44 /**
45  * Handles a cycle of reading / writing on the {@code Client}.
46  */
47 class ClientReader {
48     private final DataReader callback;
49     private final ChatServer chatServer;
50 
ClientReader(ChatServer chatServer, DataReader callback)51     ClientReader(ChatServer chatServer, DataReader callback) {
52         this.chatServer = chatServer;
53         this.callback = callback;
54     }
55 
acceptsMessages()56     public boolean acceptsMessages() {
57         return callback.acceptsMessages();
58     }
59 
60     /**
61      * Runs a cycle of doing a beforeRead action and then enqueuing a new
62      * read on the client. Handles closed channels and errors while reading.
63      * If the client is still connected a new round of actions are called.
64      */
run(final Client client)65     public void run(final Client client) {
66         callback.beforeRead(client);
67         client.read(new CompletionHandler<Integer, ByteBuffer>() {
68             @Override
69             public void completed(Integer result, ByteBuffer buffer) {
70                 // if result is negative or zero the connection has been closed or something gone wrong
71                 if (result < 1) {
72                     client.close();
73                     System.out.println("Closing connection to " + client);
74                     chatServer.removeClient(client);
75                 } else {
76                     callback.onData(client, buffer, result);
77                     // enqueue next round of actions
78                     client.run();
79                 }
80             }
81 
82             @Override
83             public void failed(Throwable exc, ByteBuffer buffer) {
84                 client.close();
85                 chatServer.removeClient(client);
86             }
87         });
88     }
89 }
90