com.zynaptic.reaction.util
Class FixedUpMonotonicClock

java.lang.Object
  com.zynaptic.reaction.util.FixedUpMonotonicClock

All Implemented Interfaces:

MonotonicClockSource

public final class FixedUpMonotonicClock
extends java.lang.Object
implements MonotonicClockSource

Implements a monotonic clock source derived from the standard Java wallclock. This monotonic clock variant uses the standard Java millisecond clock which is susceptible to changes made to the underlying wallclock. It works around potential changes to the wallclock time by maintaining a clock offset which is updated when the wallclock is observed to go backwards or jump too far into the future.

To minimise timing errors when such discontinuities occur, a sleepy thread makes regular calls to getMsTime, since timed calls to the thread sleep method are assumed to be independent of the wallclock time. This places an upper limit on the interval between requests to getMsTime.

Constructor Summary

FixedUpMonotonicClock()

Method Summary

long	getMsTime() Gets the elapsed time since the monotonic clock source was initialised.
void	init() Initialises the monotonic clock source.

Methods inherited from class java.lang.Object

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

Constructor Detail

FixedUpMonotonicClock

public FixedUpMonotonicClock()

Method Detail

getMsTime

public final long getMsTime()

Description copied from interface: MonotonicClockSource

Gets the elapsed time since the monotonic clock source was initialised. This method is called in order to obtain the current time, defined as the integer number of milliseconds since the monotonic clock source was initialised.

Specified by:

getMsTime in interface MonotonicClockSource

Returns:

Returns the monotonic time since the clock was initialised, specified in milliseconds. Returns invalid data if the clock has not been initialised.

init

public final void init()

Description copied from interface: MonotonicClockSource

Initialises the monotonic clock source. This method is called on startup by the reactor in order to initialise the timebase clock. It resets the current clock time value to 0 and then sets the timer counter running.

Specified by:

init in interface MonotonicClockSource