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examples.ntp.NTPClient |
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1 | package examples.ntp; |
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2 | /* |
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3 | * Copyright 2001-2005 The Apache Software Foundation |
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4 | * |
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5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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6 | * you may not use this file except in compliance with the License. |
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7 | * You may obtain a copy of the License at |
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8 | * |
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9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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10 | * |
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11 | * Unless required by applicable law or agreed to in writing, software |
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12 | * distributed under the License is distributed on an "AS IS" BASIS, |
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13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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14 | * See the License for the specific language governing permissions and |
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15 | * limitations under the License. |
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16 | */ |
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17 | ||
18 | import java.io.IOException; |
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19 | import java.net.InetAddress; |
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20 | import java.net.SocketException; |
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21 | import java.net.UnknownHostException; |
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22 | import java.text.NumberFormat; |
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23 | ||
24 | import org.apache.commons.net.ntp.*; |
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25 | ||
26 | /*** |
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27 | * This is an example program demonstrating how to use the NTPUDPClient |
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28 | * class. This program sends a Datagram client request packet to a |
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29 | * Network time Protocol (NTP) service port on a specified server, |
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30 | * retrieves the time, and prints it to standard output along with |
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31 | * the fields from the NTP message header (e.g. stratum level, reference id, |
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32 | * poll interval, root delay, mode, ...) |
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33 | * See <A HREF="ftp://ftp.rfc-editor.org/in-notes/rfc868.txt"> the spec </A> |
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34 | * for details. |
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35 | * <p> |
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36 | * Usage: NTPClient <hostname-or-address-list> |
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37 | * <br> |
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38 | * Example: NTPClient clock.psu.edu |
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39 | * |
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40 | * @author Jason Mathews, MITRE Corp |
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41 | ***/ |
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42 | 0 | public final class NTPClient |
43 | { |
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44 | ||
45 | 0 | private static final NumberFormat numberFormat = new java.text.DecimalFormat("0.00"); |
46 | ||
47 | /** |
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48 | * Process <code>TimeInfo</code> object and print its details. |
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49 | * @param info <code>TimeInfo</code> object. |
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50 | */ |
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51 | public static void processResponse(TimeInfo info) |
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52 | { |
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53 | 0 | NtpV3Packet message = info.getMessage(); |
54 | 0 | int stratum = message.getStratum(); |
55 | String refType; |
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56 | 0 | if (stratum <= 0) |
57 | 0 | refType = "(Unspecified or Unavailable)"; |
58 | 0 | else if (stratum == 1) |
59 | 0 | refType = "(Primary Reference; e.g., GPS)"; // GPS, radio clock, etc. |
60 | else |
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61 | 0 | refType = "(Secondary Reference; e.g. via NTP or SNTP)"; |
62 | // stratum should be 0..15... |
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63 | 0 | System.out.println(" Stratum: " + stratum + " " + refType); |
64 | 0 | int version = message.getVersion(); |
65 | 0 | int li = message.getLeapIndicator(); |
66 | 0 | System.out.println(" leap=" + li + ", version=" |
67 | + version + ", precision=" + message.getPrecision()); |
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68 | ||
69 | 0 | System.out.println(" mode: " + message.getModeName() + " (" + message.getMode() + ")"); |
70 | 0 | int poll = message.getPoll(); |
71 | // poll value typically btwn MINPOLL (4) and MAXPOLL (14) |
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72 | 0 | System.out.println(" poll: " + (poll <= 0 ? 1 : (int) Math.pow(2, poll)) |
73 | + " seconds" + " (2 ** " + poll + ")"); |
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74 | 0 | double disp = message.getRootDispersionInMillisDouble(); |
75 | 0 | System.out.println(" rootdelay=" + numberFormat.format(message.getRootDelayInMillisDouble()) |
76 | + ", rootdispersion(ms): " + numberFormat.format(disp)); |
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77 | ||
78 | 0 | int refId = message.getReferenceId(); |
79 | 0 | String refAddr = NtpUtils.getHostAddress(refId); |
80 | 0 | String refName = null; |
81 | 0 | if (refId != 0) { |
82 | 0 | if (refAddr.equals("127.127.1.0")) { |
83 | 0 | refName = "LOCAL"; // This is the ref address for the Local Clock |
84 | 0 | } else if (stratum >= 2) { |
85 | // If reference id has 127.127 prefix then it uses its own reference clock |
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86 | // defined in the form 127.127.clock-type.unit-num (e.g. 127.127.8.0 mode 5 |
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87 | // for GENERIC DCF77 AM; see refclock.htm from the NTP software distribution. |
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88 | 0 | if (!refAddr.startsWith("127.127")) { |
89 | try { |
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90 | 0 | InetAddress addr = InetAddress.getByName(refAddr); |
91 | 0 | String name = addr.getHostName(); |
92 | 0 | if (name != null && !name.equals(refAddr)) |
93 | 0 | refName = name; |
94 | 0 | } catch (UnknownHostException e) { |
95 | // some stratum-2 servers sync to ref clock device but fudge stratum level higher... (e.g. 2) |
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96 | // ref not valid host maybe it's a reference clock name? |
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97 | // otherwise just show the ref IP address. |
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98 | 0 | refName = NtpUtils.getReferenceClock(message); |
99 | 0 | } |
100 | } |
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101 | 0 | } else if (version >= 3 && (stratum == 0 || stratum == 1)) { |
102 | 0 | refName = NtpUtils.getReferenceClock(message); |
103 | // refname usually have at least 3 characters (e.g. GPS, WWV, LCL, etc.) |
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104 | } |
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105 | // otherwise give up on naming the beast... |
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106 | } |
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107 | 0 | if (refName != null && refName.length() > 1) |
108 | 0 | refAddr += " (" + refName + ")"; |
109 | 0 | System.out.println(" Reference Identifier:\t" + refAddr); |
110 | ||
111 | 0 | TimeStamp refNtpTime = message.getReferenceTimeStamp(); |
112 | 0 | System.out.println(" Reference Timestamp:\t" + refNtpTime + " " + refNtpTime.toDateString()); |
113 | ||
114 | // Originate Time is time request sent by client (t1) |
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115 | 0 | TimeStamp origNtpTime = message.getOriginateTimeStamp(); |
116 | 0 | System.out.println(" Originate Timestamp:\t" + origNtpTime + " " + origNtpTime.toDateString()); |
117 | ||
118 | 0 | long destTime = info.getReturnTime(); |
119 | // Receive Time is time request received by server (t2) |
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120 | 0 | TimeStamp rcvNtpTime = message.getReceiveTimeStamp(); |
121 | 0 | System.out.println(" Receive Timestamp:\t" + rcvNtpTime + " " + rcvNtpTime.toDateString()); |
122 | ||
123 | // Transmit time is time reply sent by server (t3) |
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124 | 0 | TimeStamp xmitNtpTime = message.getTransmitTimeStamp(); |
125 | 0 | System.out.println(" Transmit Timestamp:\t" + xmitNtpTime + " " + xmitNtpTime.toDateString()); |
126 | ||
127 | // Destination time is time reply received by client (t4) |
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128 | 0 | TimeStamp destNtpTime = TimeStamp.getNtpTime(destTime); |
129 | 0 | System.out.println(" Destination Timestamp:\t" + destNtpTime + " " + destNtpTime.toDateString()); |
130 | ||
131 | 0 | info.computeDetails(); // compute offset/delay if not already done |
132 | 0 | Long offsetValue = info.getOffset(); |
133 | 0 | Long delayValue = info.getDelay(); |
134 | 0 | String delay = (delayValue == null) ? "N/A" : delayValue.toString(); |
135 | 0 | String offset = (offsetValue == null) ? "N/A" : offsetValue.toString(); |
136 | ||
137 | 0 | System.out.println(" Roundtrip delay(ms)=" + delay |
138 | + ", clock offset(ms)=" + offset); // offset in ms |
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139 | 0 | } |
140 | ||
141 | public static final void main(String[] args) |
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142 | { |
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143 | 0 | if (args == null || args.length == 0) { |
144 | 0 | System.err.println("Usage: NTPClient <hostname-or-address-list>"); |
145 | 0 | System.exit(1); |
146 | } |
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147 | ||
148 | 0 | NTPUDPClient client = new NTPUDPClient(); |
149 | // We want to timeout if a response takes longer than 10 seconds |
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150 | 0 | client.setDefaultTimeout(10000); |
151 | try { |
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152 | 0 | client.open(NtpV3Packet.NTP_PORT); |
153 | 0 | for (int i = 0; i < args.length; i++) |
154 | { |
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155 | 0 | System.out.println(); |
156 | try { |
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157 | 0 | InetAddress hostAddr = InetAddress.getByName(args[i]); |
158 | 0 | System.out.println("> " + hostAddr.getHostName() + "/" + hostAddr.getHostAddress()); |
159 | 0 | TimeInfo info = client.getTime(hostAddr); |
160 | 0 | processResponse(info); |
161 | 0 | } catch (IOException ioe) { |
162 | 0 | ioe.printStackTrace(); |
163 | 0 | } |
164 | } |
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165 | 0 | } catch (SocketException e) { |
166 | 0 | e.printStackTrace(); |
167 | 0 | } |
168 | ||
169 | 0 | client.close(); |
170 | 0 | } |
171 | ||
172 | } |
This report is generated by jcoverage, Maven and Maven JCoverage Plugin. |