tijos.framework.networkcenter.ntp

Class NTPUDPClient

java.lang.Object

tijos.framework.networkcenter.ntp.NTPUDPClient

public final class NTPUDPClient
extends Object

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. Note: UTC time only, timezone is not used

Version:

$Revision: 1747119 $

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_PORT The default NTP port.

Constructor Summary

Constructors

Constructor and Description
NTPUDPClient()

Method Summary

Modifier and Type	Method and Description
TimeInfo	getTime(InetAddress host) Retrieves the time information from the specified server on the default NTP port and returns it.
TimeInfo	getTime(InetAddress host, int port) Retrieves the time information from the specified server and 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	setDefaultTimeout(int timeout) Set the default timeout in milliseconds to use when opening a socket.
void	setVersion(int version) Sets the NTP protocol version number that client sets on request packet communicate with remote host.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_PORT

public static final int DEFAULT_PORT

The default NTP port. It is set to 123 according to RFC 1305.

See Also:

Constant Field Values

Constructor Detail

NTPUDPClient

public NTPUDPClient()

Method Detail

getTime

public TimeInfo getTime(InetAddress host)
                 throws IOException

Retrieves the time information from the specified server on the default NTP port and returns it. The time is the number of milliseconds 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 a NTP error occurs while retrieving the time.

getTime

public TimeInfo getTime(InetAddress host,
                        int port)
                 throws IOException

Retrieves the time information from the specified server and port and returns it. The time is the number of milliseconds 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 a NTP error occurs while retrieving the time.

getVersion

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:

setVersion(int)

setDefaultTimeout

public void setDefaultTimeout(int timeout)

Set the default timeout in milliseconds to use when opening a socket. After a call to open, the timeout for the socket is set using this value. which operates on the currently open socket. _timeout_ contains the new timeout value.

Parameters:

timeout - The timeout in milliseconds to use for the datagram socket connection.

setVersion

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