001 package org.apache.commons.net.time;
002
003 /*
004 * Licensed to the Apache Software Foundation (ASF) under one or more
005 * contributor license agreements. See the NOTICE file distributed with
006 * this work for additional information regarding copyright ownership.
007 * The ASF licenses this file to You under the Apache License, Version 2.0
008 * (the "License"); you may not use this file except in compliance with
009 * the License. You may obtain a copy of the License at
010 *
011 * http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019
020 import java.io.DataOutputStream;
021 import java.io.IOException;
022 import java.net.ServerSocket;
023 import java.net.Socket;
024
025 /**
026 * The TimetSimpleServer class is a simple TCP implementation of a server
027 * for the Time Protocol described in RFC 868.
028 * <p>
029 * Listens for TCP socket connections on the time protocol port and writes
030 * the local time to socket outputStream as 32-bit integer of seconds
031 * since midnight on 1 January 1900 GMT.
032 * See <A HREF="ftp://ftp.rfc-editor.org/in-notes/rfc868.txt"> the spec </A> for
033 * details.
034 * <p>
035 * Note this is for <B>debugging purposes only</B> and not meant to be run as a realiable time service.
036 *
037 * @author Jason Mathews, MITRE Corporation
038 *
039 * @version $Revision: 658518 $ $Date: 2008-05-21 02:04:30 +0100 (Wed, 21 May 2008) $
040 */
041 public class TimeTestSimpleServer implements Runnable
042 {
043
044 /**
045 * baseline time 1900-01-01T00:00:00 UTC
046 */
047 public static final long SECONDS_1900_TO_1970 = 2208988800L;
048
049 /*** The default time port. It is set to 37 according to RFC 868. ***/
050 public static final int DEFAULT_PORT = 37;
051
052 private ServerSocket server;
053 private int port;
054 private boolean running = false;
055
056 /**
057 * Default constructor for TimetSimpleServer.
058 * Initializes port to defaul time port.
059 */
060 public TimeTestSimpleServer()
061 {
062 port = DEFAULT_PORT;
063 }
064
065 /**
066 * Constructor for TimetSimpleServer given a specific port.
067 */
068 public TimeTestSimpleServer(int port)
069 {
070 this.port = port;
071 }
072
073 public void connect() throws IOException
074 {
075 if (server == null)
076 {
077 server = new ServerSocket(port);
078 }
079 }
080
081 public int getPort()
082 {
083 return server == null ? port : server.getLocalPort();
084 }
085
086 public boolean isRunning()
087 {
088 return running;
089 }
090
091 /**
092 * Start time service and provide time to client connections.
093 * @throws IOException
094 */
095 public void start() throws IOException
096 {
097 if (server == null)
098 {
099 connect();
100 }
101 if (!running)
102 {
103 running = true;
104 new Thread(this).start();
105 }
106 }
107
108 public void run()
109 {
110 Socket socket = null;
111 while (running)
112 {
113 try
114 {
115 socket = server.accept();
116 DataOutputStream os = new DataOutputStream(socket.getOutputStream());
117 // add 500 ms to round off to nearest second
118 int time = (int) ((System.currentTimeMillis() + 500) / 1000 + SECONDS_1900_TO_1970);
119 os.writeInt(time);
120 os.flush();
121 } catch (IOException e)
122 {
123 } finally
124 {
125 if (socket != null)
126 try
127 {
128 socket.close(); // force closing of the socket
129 } catch (IOException e)
130 {
131 System.err.println("close socket error: " + e);
132 }
133 }
134 }
135 }
136
137 /**
138 * Close server socket.
139 */
140 public void stop()
141 {
142 running = false;
143 if (server != null)
144 {
145 try
146 {
147 server.close(); // force closing of the socket
148 } catch (IOException e)
149 {
150 System.err.println("close socket error: " + e);
151 }
152 server = null;
153 }
154 }
155
156 public static void main(String[] args)
157 {
158 TimeTestSimpleServer server = new TimeTestSimpleServer();
159 try
160 {
161 server.start();
162 } catch (IOException e)
163 {
164 }
165 }
166
167 }