com.antelmann.calendar
Class NTPTime

java.lang.Object
  com.antelmann.calendar.NTPTime

All Implemented Interfaces:

TimeSystem

public class NTPTime
extends Object
implements TimeSystem

works based on a NTPClient instance adding reliability by using multiple servers if one fails.

Author:

Holger Antelmann

See Also:

NTPClient

Field Summary

Fields inherited from interface com.antelmann.calendar.TimeSystem

SYSTEM_TIME

Constructor Summary

NTPTime()
immediately activates the instance and schedules updates in the interval given.

NTPTime(boolean activateNow)
Interval is 12h.

NTPTime(boolean activateNow, long updateIntervalMillis)
immediately activates the instance and schedules updates in the interval given.

NTPTime(boolean activateNow, long updateIntervalMillis, Logger logger)

NTPTime(boolean activateNow, long updateIntervalMillis, NTPClient client)

NTPTime(boolean activateNow, long updateIntervalMillis, NTPClient client, Logger logger)

Method Summary

void	activate() activates the embedded timer for automatic updates
boolean	addServer(String server)
long	currentTimeMillis() returns the current time
void	deactivate() deactivates the embedded timer for automatic updates
protected void	finalize()
Logger	getLogger()
NTPClient	getNtpClient() returns the clock in use
String[]	getServerNames()
long	getUpdateIntervalMillis()
boolean	isActivated()
boolean	removeServer(String server)
void	setUpdateIntervalMillis(long updateIntervalMillis) must be called while the instance is deactivated.

Methods inherited from class java.lang.Object

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

Constructor Detail

NTPTime

public NTPTime()

immediately activates the instance and schedules updates in the interval given. Interval is 24h.

NTPTime

public NTPTime(boolean activateNow)

Interval is 12h.

NTPTime

public NTPTime(boolean activateNow,
               long updateIntervalMillis)
        throws IllegalArgumentException

immediately activates the instance and schedules updates in the interval given.

Parameters:

updateIntervalMillis - must represent more than a minute

Throws:

IllegalArgumentException - if the interval represents less than a minute

NTPTime

public NTPTime(boolean activateNow,
               long updateIntervalMillis,
               Logger logger)
        throws IllegalArgumentException

Throws:

IllegalArgumentException

NTPTime

public NTPTime(boolean activateNow,
               long updateIntervalMillis,
               NTPClient client)
        throws IllegalArgumentException

Throws:

IllegalArgumentException

NTPTime

public NTPTime(boolean activateNow,
               long updateIntervalMillis,
               NTPClient client,
               Logger logger)
        throws IllegalArgumentException

Parameters:

activateNow - if true, the instance is immediately activated

updateIntervalMillis - must represent more than a minute

client - the NTPClient that is to be used with this instance

logger - used to log the scheduled delta updates for the ntp clock

Throws:

IllegalArgumentException - if the interval represents less than 5 minutes

Method Detail

isActivated

public boolean isActivated()

getUpdateIntervalMillis

public long getUpdateIntervalMillis()

setUpdateIntervalMillis

public void setUpdateIntervalMillis(long updateIntervalMillis)
                             throws IllegalStateException,
                                    IllegalArgumentException

must be called while the instance is deactivated.

Throws:

IllegalStateException - if this instance is currently activated

IllegalArgumentException - if the interval represents less than 5 minutes

See Also:

isActivated()

activate

public void activate()

activates the embedded timer for automatic updates

deactivate

public void deactivate()

deactivates the embedded timer for automatic updates

finalize

protected void finalize()

Overrides:

finalize in class Object

currentTimeMillis

public long currentTimeMillis()

returns the current time

Specified by:

currentTimeMillis in interface TimeSystem

Returns:

the difference, measured in milliseconds, between the current time and midnight, January 1, 1970 UTC.

getNtpClient

public NTPClient getNtpClient()

returns the clock in use

getLogger

public Logger getLogger()

getServerNames

public String[] getServerNames()

addServer

public boolean addServer(String server)

removeServer

public boolean removeServer(String server)