com.antelmann.calendar
Class AbstractTimeSystem

java.lang.Object
  com.antelmann.calendar.AbstractTimeSystem

All Implemented Interfaces:

TimeSystem

Direct Known Subclasses:

NTPClient

public abstract class AbstractTimeSystem
extends Object
implements TimeSystem

the basis for a custom TimeSystem based on an offset value (delta) relative to the system time.

Author:

Holger Antelmann

Field Summary

Fields inherited from interface com.antelmann.calendar.TimeSystem

SYSTEM_TIME

Constructor Summary

AbstractTimeSystem()

Method Summary

long	adjustDelta() adjusts the delta value used for getTime() through using the server time
long	adjustedTimeMills()
protected abstract long	aquireDelta() returns the current difference between system time and the time of this implementation in milliseconds.
TimerTask	createTimerTask(Logger logger) creates a TimerTask that will adjust the delta and log the result to the given logger.
long	currentTimeMillis() returns the system time adjusted by the delta value.
long	getDelta() returns the stored difference between system time and atomic time in milliseconds.
long	getLastDeltaAdjustmentTime() returns the system time when adjustDelta() has been successfully called last time.
long	getLastRoundTripDelay() returns the time of the time it took to adjust the delta the last time the adjustment was made.
protected void	setDelta(long delta) manually sets the value used to adjust system time
void	setLastRoundTripDelay(long lastRoundTripDelay)

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractTimeSystem

public AbstractTimeSystem()

Method Detail

currentTimeMillis

public long currentTimeMillis()

returns the system time adjusted by the delta value. This is generally the proper method to be called by the application.

Specified by:

currentTimeMillis in interface TimeSystem

Returns:

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

adjustedTimeMills

public long adjustedTimeMills()
                       throws IOException

Throws:

IOException

aquireDelta

protected abstract long aquireDelta()
                             throws IOException

returns the current difference between system time and the time of this implementation in milliseconds. A negative number indicates that the system clock is behind. Calling this method does not affect the delta value of this instance.

Throws:

IOException

See Also:

adjustDelta()

getDelta

public long getDelta()

returns the stored difference between system time and atomic time in milliseconds. A negative number indicates that the system clock is behind.

See Also:

adjustDelta(), setDelta(long)

setDelta

protected void setDelta(long delta)

manually sets the value used to adjust system time

See Also:

adjustDelta()

getLastDeltaAdjustmentTime

public long getLastDeltaAdjustmentTime()

returns the system time when adjustDelta() has been successfully called last time. If no successful adjustment has taken place, yet, the method returns 0.

See Also:

adjustDelta()

getLastRoundTripDelay

public long getLastRoundTripDelay()

returns the time of the time it took to adjust the delta the last time the adjustment was made. If no successful adjustment has taken place, yet, the method returns -1.

setLastRoundTripDelay

public void setLastRoundTripDelay(long lastRoundTripDelay)

adjustDelta

public long adjustDelta()
                 throws IOException

adjusts the delta value used for getTime() through using the server time

Throws:

IOException

See Also:

currentTimeMillis(), getDelta(), setDelta(long), getLastDeltaAdjustmentTime(), getLastRoundTripDelay()

createTimerTask

public TimerTask createTimerTask(Logger logger)

creates a TimerTask that will adjust the delta and log the result to the given logger. The logger may be null.

See Also:

adjustDelta(), Timer