1 /*
2 * Copyright 2006 Simon Raess
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package net.sf.beep4j.internal.tcp;
17
18 import net.sf.beep4j.Message;
19
20 /**
21 * Controller object that knows about the channel's send and receive
22 * buffers. It's main purpose is sending SEQ frames when the controller
23 * thinks that's necessary as well as to fragment / queue outgoing
24 * messages to respect the window of the other peer.
25 *
26 * @author Simon Raess
27 */
28 public interface ChannelController {
29
30 /**
31 * To be invoked whenever a SEQ frame is received to update the sender
32 * window. The window start will be placed at <var>ackno</var> and
33 * the size will be updated to <var>size</var>. Note that the position
34 * will remain unaffected. If ackno is larger than the window size
35 * the communication with the other peer should be stopped as the
36 * peers lost the synchronization.
37 *
38 * @param ackno the acknowledged sequence number
39 * @param size the size of the window
40 */
41 void updateSendWindow(long ackno, int size);
42
43 /**
44 * Send an ANS message with the given messageNumber and answerNumber on
45 * the channel of this controller.
46 *
47 * @param messageNumber the message number of the message
48 * @param answerNumber the answer number of the message
49 * @param message the Message to be sent
50 */
51 void sendANS(int messageNumber, int answerNumber, Message message);
52
53 /**
54 * Sends an NUL message with the given messageNumber on the channel
55 * of this controller.
56 *
57 * @param messageNumber the message number of the Message
58 */
59 void sendNUL(int messageNumber);
60
61 /**
62 * Sends an ERR message with the given messageNumber on the channel
63 * of this controller.
64 *
65 * @param messageNumber the message number of the Message
66 * @param message the Message to be sent
67 */
68 void sendERR(int messageNumber, Message message);
69
70 /**
71 * Sends an MSG message with the given messageNumber on the channel
72 * of this controller.
73 *
74 * @param messageNumber the message number of the Message
75 * @param message the Message to be sent
76 */
77 void sendMSG(int messageNumber, Message message);
78
79 /**
80 * Sends an RPY message with the given messageNumber on the channel
81 * of this controller.
82 *
83 * @param messageNumber the message number of the Message
84 * @param message the Message to be sent
85 */
86 void sendRPY(int messageNumber, Message message);
87
88 /**
89 * <p>Validation of the sequence number according to the BEEP specification section
90 * 2.2.1.1.</p>
91 *
92 * <p>A frame is poorly formed if the value of the sequence number doesn't
93 * correspond to the expected value for the associated channel.</p>
94 *
95 * <p>Further, this method checks that the payload size is not greater than
96 * the remaining buffer space.</p>
97 */
98 void checkFrame(long seqno, int payloadSize);
99
100 /**
101 * Notifies the controller that the frame with sequence number <var>seqno</var>
102 * and size <var>size</var> has been completely received.
103 *
104 * @param seqno the sequence number of the frame
105 * @param size the size of the frame
106 */
107 void frameReceived(long seqno, int size);
108
109 }