1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.net.time;
19
20 import java.io.DataOutputStream;
21 import java.io.IOException;
22 import java.net.ServerSocket;
23 import java.net.Socket;
24
25 /**
26 * The TimetSimpleServer class is a simple TCP implementation of a server for the Time Protocol described in RFC 868.
27 * <p>
28 * Listens for TCP socket connections on the time protocol port and writes the local time to socket outputStream as 32-bit integer of seconds since midnight on
29 * 1 January 1900 GMT. See <A HREF="ftp://ftp.rfc-editor.org/in-notes/rfc868.txt"> the spec </A> for details.
30 * <p>
31 * Note this is for <B>debugging purposes only</B> and not meant to be run as a realiable time service.
32 */
33 public class TimeTestSimpleServer implements Runnable {
34
35 /**
36 * baseline time 1900-01-01T00:00:00 UTC
37 */
38 public static final long SECONDS_1900_TO_1970 = 2208988800L;
39
40 /** The default time port. It is set to 37 according to RFC 868. */
41 public static final int DEFAULT_PORT = 37;
42
43 public static void main(final String[] args) {
44 final TimeTestSimpleServer server = new TimeTestSimpleServer();
45 try {
46 server.start();
47 } catch (final IOException e) {
48 // ignored
49 }
50 }
51
52 private ServerSocket server;
53 private final int port;
54
55 private boolean running;
56
57 public TimeTestSimpleServer() {
58 port = DEFAULT_PORT;
59 }
60
61 public TimeTestSimpleServer(final int port) {
62 this.port = port;
63 }
64
65 public void connect() throws IOException {
66 if (server == null) {
67 server = new ServerSocket(port);
68 }
69 }
70
71 public int getPort() {
72 return server == null ? port : server.getLocalPort();
73 }
74
75 public boolean isRunning() {
76 return running;
77 }
78
79 @Override
80 public void run() {
81 Socket socket = null;
82 while (running) {
83 try {
84 socket = server.accept();
85 final DataOutputStream os = new DataOutputStream(socket.getOutputStream());
86 // add 500 ms to round off to nearest second
87 final int time = (int) ((System.currentTimeMillis() + 500) / 1000 + SECONDS_1900_TO_1970);
88 os.writeInt(time);
89 os.flush();
90 } catch (final IOException e) {
91 // ignored
92 } finally {
93 if (socket != null) {
94 try {
95 socket.close(); // force closing of the socket
96 } catch (final IOException e) {
97 System.err.println("close socket error: " + e);
98 }
99 }
100 }
101 }
102 }
103
104 /*
105 * Start time service and provide time to client connections.
106 */
107 public void start() throws IOException {
108 if (server == null) {
109 connect();
110 }
111 if (!running) {
112 running = true;
113 new Thread(this).start();
114 }
115 }
116
117 /*
118 * Close server socket.
119 */
120 public void stop() {
121 running = false;
122 if (server != null) {
123 try {
124 server.close(); // force closing of the socket
125 } catch (final IOException e) {
126 System.err.println("close socket error: " + e);
127 }
128 server = null;
129 }
130 }
131
132 }