org.apache.commons.net.ntp
Class NTPUDPClient
public final
class
NTPUDPClient
extends DatagramSocketClient
The NTPUDPClient class is a UDP implementation of a client for the
Network Time Protocol (NTP) described in RFC 1305 as well as the
Simple Network Time Protocol (SNTP) in RFC-2030. To use the class,
merely open a local datagram socket with
open
and call
getTime to retrieve the time. Then call
close
to close the connection properly.
Successive calls to
getTime are permitted
without re-establishing a connection. That is because UDP is a
connectionless protocol and the Network Time Protocol is stateless.
Version: $Revision: 165675 $ $Date: 2005-05-02 15:09:55 -0500 (Mon, 02 May 2005) $
Author: Jason Mathews, MITRE Corp
Method Summary |
TimeInfo | getTime(InetAddress host, int port)
Retrieves the time information from the specified server and port and
returns it. |
TimeInfo | getTime(InetAddress host)
Retrieves the time information from the specified server on the
default NTP port and returns it. |
int | getVersion()
Returns the NTP protocol version number that client sets on request packet
that is sent to remote host (e.g. |
void | setVersion(int version)
Sets the NTP protocol version number that client sets on request packet
communicate with remote host.
|
public static final int DEFAULT_PORT
The default NTP port. It is set to 123 according to RFC 1305. **
public
TimeInfo getTime(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.
Parameters: host The address of the server. port The port of the service.
Returns: The time value retrieved from the server.
Throws: IOException If an error occurs while retrieving the time.
public
TimeInfo getTime(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.
Parameters: host The address of the server.
Returns: The time value retrieved from the server.
Throws: IOException If an error occurs while retrieving the time.
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.)
Returns: the NTP protocol version number that client sets on request packet.
See Also:
public void setVersion(int version)
Sets the NTP protocol version number that client sets on request packet
communicate with remote host.
Parameters: version the NTP protocol version number