File	Doc	Category	Size	Date	Package
NTPUDPClient.java	API Doc	Apache Commons NET 1.4.1 API	5268	Sat Dec 03 10:05:48 GMT 2005	org.apache.commons.net.ntp

NTPUDPClient

• java.lang.Object
  • org.apache.commons.net.DatagramSocketClient

Fields Summary
public static final int	DEFAULT_PORT The default NTP port. It is set to 123 according to RFC 1305.
private int	_version

Constructors Summary

Methods Summary
public TimeInfo	getTime(java.net.InetAddress host, int port) Retrieves the time information from the specified server and port and returns it. The time is the number of miliiseconds since 00:00 (midnight) 1 January 1900 UTC, as specified by RFC 1305. This method reads the raw NTP packet and constructs a TimeInfo object that allows access to all the fields of the NTP message header. param host The address of the server. param port The port of the service. return The time value retrieved from the server. exception IOException If an error occurs while retrieving the time. // if not connected then open to next available UDP port if (!isOpen()) { open(); } NtpV3Packet message = new NtpV3Impl(); message.setMode(NtpV3Packet.MODE_CLIENT); message.setVersion(_version); DatagramPacket sendPacket = message.getDatagramPacket(); sendPacket.setAddress(host); sendPacket.setPort(port); NtpV3Packet recMessage = new NtpV3Impl(); DatagramPacket receivePacket = recMessage.getDatagramPacket(); /* * Must minimize the time between getting the current time, * timestamping the packet, and sending it out which * introduces an error in the delay time. * No extraneous logging and initializations here !!! */ TimeStamp now = TimeStamp.getCurrentTime(); // Note that if you do not set the transmit time field then originating time // in server response is all 0's which is "Thu Feb 07 01:28:16 EST 2036". message.setTransmitTime(now); _socket_.send(sendPacket); _socket_.receive(receivePacket); long returnTime = System.currentTimeMillis(); // create TimeInfo message container but don't pre-compute the details yet TimeInfo info = new TimeInfo(recMessage, returnTime, false); return info;
public TimeInfo	getTime(java.net.InetAddress host) Retrieves the time information from the specified server on the default NTP port and returns it. The time is the number of miliiseconds since 00:00 (midnight) 1 January 1900 UTC, as specified by RFC 1305. This method reads the raw NTP packet and constructs a TimeInfo object that allows access to all the fields of the NTP message header. param host The address of the server. return The time value retrieved from the server. exception IOException If an error occurs while retrieving the time. return getTime(host, NtpV3Packet.NTP_PORT);
public int	getVersion() Returns the NTP protocol version number that client sets on request packet that is sent to remote host (e.g. 3=NTP v3, 4=NTP v4, etc.) return the NTP protocol version number that client sets on request packet. see #setVersion(int) return _version;
public void	setVersion(int version) Sets the NTP protocol version number that client sets on request packet communicate with remote host. param version the NTP protocol version number _version = version;