net.time4j.clock

Interface NetTimeConfiguration

All Known Subinterfaces:

SntpConfiguration

public interface NetTimeConfiguration

Contains the configuration parameters of a connection to an internet time server.

Implementations of this SPI-interface must be immutable or at least threadsafe. Instances can be created manually or via a ServiceLoader.

Since:

2.1

Author:

Meno Hochschild

See Also:

NetTimeConnector, ServiceLoader

Specification:

Implementations must have a public constructor without any arguments.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_CONNECTION_TIMEOUT Default timeout is 60 seconds.

Method Summary

Modifier and Type	Method and Description
int	getClockShiftWindow() Determines the time window within which an existing shift between the local clock and the internet clock will be synchronized (after a successful connection) if the local clock is too quick.
int	getConnectionTimeout() Determines the maximum time out when connecting to an internet time server.
String	getTimeServerAddress() Yields the internet address of a time server.
int	getTimeServerPort() Yields the port of a time server.

Field Detail

DEFAULT_CONNECTION_TIMEOUT

static final int DEFAULT_CONNECTION_TIMEOUT

Default timeout is 60 seconds.

See Also:

Constant Field Values

Method Detail

getTimeServerAddress

String getTimeServerAddress()

Yields the internet address of a time server.

Possible values are also addresses of older time servers which still support the elder protocol (RFC 867), for example:

• time.nist.gov (US-government)
• time.ien.it (electrotechn. institute in Italy)

Alternatively, addresses of modern NTP-servers are permitted which support the protocols NTP3 or NTP4:

• ptbtime1.ptb.de
• ptbtime2.ptb.de
• ntp2.lrz-muenchen.de

Returns:

time server address

Since:

2.1

getTimeServerPort

int getTimeServerPort()

Yields the port of a time server.

The DAYTIME-protocol assumes as default value 13 while NTP-protocols usually use the value 123.

Returns:

int

Since:

2.1

getConnectionTimeout

int getConnectionTimeout()

Determines the maximum time out when connecting to an internet time server.

The value 0 indicates an unlimited waiting time. The default value is internally 60 seconds.

Returns:

maximum waiting time in seconds >= 0

Since:

2.1

See Also:

DEFAULT_CONNECTION_TIMEOUT

getClockShiftWindow

int getClockShiftWindow()

Determines the time window within which an existing shift between the local clock and the internet clock will be synchronized (after a successful connection) if the local clock is too quick.

The value 0 causes the immediate synchronization and is the default. Else the local clock will only be synchronized with the internet clock after this clock shift window has been passed. Within this time window the local clock will be slowly adjusted to the internet clock. The time window should always be choosen such that it is smaller than the time between two connections. Its main purpose is slowing down a local clock such that applications will not notice any backwards running time within the scope of expected precision.

If the local clock is too slow however then the synchronization will happen immediately, and this configuration parameter is not applied.

Returns:

time window in seconds (>= 0)

Since:

2.1