Package akka.actor

Class LightArrayRevolverScheduler

java.lang.Object

akka.actor.LightArrayRevolverScheduler

All Implemented Interfaces:

Scheduler, java.io.Closeable, java.lang.AutoCloseable

public class LightArrayRevolverScheduler
extends java.lang.Object
implements Scheduler, java.io.Closeable

This scheduler implementation is based on a revolving wheel of buckets, like Netty’s HashedWheelTimer, which it advances at a fixed tick rate and dispatches tasks it finds in the current bucket to their respective ExecutionContexts. The tasks are held in TaskHolders, which upon cancellation null out their reference to the actual task, leaving only this shell to be cleaned up when the wheel reaches that bucket next time. This enables the use of a simple linked list to chain the TaskHolders off the wheel.

Also noteworthy is that this scheduler does not obtain a current time stamp when scheduling single-shot tasks, instead it always rounds up the task delay to a full multiple of the TickDuration. This means that tasks are scheduled possibly one tick later than they could be (if checking that “now() + delay <= nextTick” were done).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	LightArrayRevolverScheduler.TaskHolder	INTERNAL API
static interface	LightArrayRevolverScheduler.TimerTask	INTERNAL API

Nested classes/interfaces inherited from interface akka.actor.Scheduler

Scheduler.TaskRunOnClose

Constructor Summary

Constructors

Constructor	Description
LightArrayRevolverScheduler(com.typesafe.config.Config config, LoggingAdapter log, java.util.concurrent.ThreadFactory threadFactory)

Method Summary

Modifier and Type	Method	Description
protected long	clock()	Clock implementation is replaceable (for testing); the implementation must return a monotonically increasing series of Long nanoseconds.
void	close()
protected scala.concurrent.duration.FiniteDuration	getShutdownTimeout()	Overridable for tests
double	maxFrequency()	The maximum supported task frequency of this scheduler, i.e.
Cancellable	schedule(scala.concurrent.duration.FiniteDuration initialDelay, scala.concurrent.duration.FiniteDuration delay, java.lang.Runnable runnable, scala.concurrent.ExecutionContext executor)	Deprecated API: See Scheduler.scheduleWithFixedDelay(scala.concurrent.duration.FiniteDuration, scala.concurrent.duration.FiniteDuration, java.lang.Runnable, scala.concurrent.ExecutionContext) or Scheduler.scheduleAtFixedRate(scala.concurrent.duration.FiniteDuration, scala.concurrent.duration.FiniteDuration, java.lang.Runnable, scala.concurrent.ExecutionContext).
Cancellable	scheduleOnce(scala.concurrent.duration.FiniteDuration delay, java.lang.Runnable runnable, scala.concurrent.ExecutionContext executor)	Scala API: Schedules a Runnable to be run once with a delay, i.e.
Cancellable	scheduleWithFixedDelay(scala.concurrent.duration.FiniteDuration initialDelay, scala.concurrent.duration.FiniteDuration delay, java.lang.Runnable runnable, scala.concurrent.ExecutionContext executor)	Scala API: Schedules a Runnable to be run repeatedly with an initial delay and a fixed delay between subsequent executions.
scala.concurrent.duration.FiniteDuration	ShutdownTimeout()
protected int	startTick()	Replaceable for testing.
scala.concurrent.duration.FiniteDuration	TickDuration()
protected void	waitNanos(long nanos)	Overridable for tests
int	WheelSize()

Methods inherited from class java.lang.Object

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

Methods inherited from interface akka.actor.Scheduler

schedule, schedule, schedule, schedule, schedule$default$6, scheduleAtFixedRate, scheduleAtFixedRate, scheduleAtFixedRate, scheduleAtFixedRate, scheduleAtFixedRate$default$6, scheduleOnce, scheduleOnce, scheduleOnce, scheduleOnce, scheduleOnce$default$5, scheduleWithFixedDelay, scheduleWithFixedDelay, scheduleWithFixedDelay, scheduleWithFixedDelay$default$6

Constructor Detail

LightArrayRevolverScheduler

public LightArrayRevolverScheduler(com.typesafe.config.Config config,
                                   LoggingAdapter log,
                                   java.util.concurrent.ThreadFactory threadFactory)

Method Detail

WheelSize

public int WheelSize()

TickDuration

public scala.concurrent.duration.FiniteDuration TickDuration()

ShutdownTimeout

public scala.concurrent.duration.FiniteDuration ShutdownTimeout()

clock

protected long clock()

Clock implementation is replaceable (for testing); the implementation must return a monotonically increasing series of Long nanoseconds.

startTick

protected int startTick()

Replaceable for testing.

getShutdownTimeout

protected scala.concurrent.duration.FiniteDuration getShutdownTimeout()

Overridable for tests

waitNanos

protected void waitNanos(long nanos)

Overridable for tests

scheduleWithFixedDelay

public Cancellable scheduleWithFixedDelay(scala.concurrent.duration.FiniteDuration initialDelay,
                                          scala.concurrent.duration.FiniteDuration delay,
                                          java.lang.Runnable runnable,
                                          scala.concurrent.ExecutionContext executor)

Description copied from interface: Scheduler

Scala API: Schedules a Runnable to be run repeatedly with an initial delay and a fixed delay between subsequent executions. E.g. if you would like the function to be run after 2 seconds and thereafter every 100ms you would set delay=Duration(2, TimeUnit.SECONDS) and interval=Duration(100, TimeUnit.MILLISECONDS).

It will not compensate the delay between tasks if the execution takes a long time or if scheduling is delayed longer than specified for some reason. The delay between subsequent execution will always be (at least) the given delay. In the long run, the frequency of execution will generally be slightly lower than the reciprocal of the specified delay.

If the Runnable throws an exception the repeated scheduling is aborted, i.e. the function will not be invoked any more.

Specified by:

scheduleWithFixedDelay in interface Scheduler

schedule

public Cancellable schedule(scala.concurrent.duration.FiniteDuration initialDelay,
                            scala.concurrent.duration.FiniteDuration delay,
                            java.lang.Runnable runnable,
                            scala.concurrent.ExecutionContext executor)

Description copied from interface: Scheduler

Deprecated API: See Scheduler.scheduleWithFixedDelay(scala.concurrent.duration.FiniteDuration, scala.concurrent.duration.FiniteDuration, java.lang.Runnable, scala.concurrent.ExecutionContext) or Scheduler.scheduleAtFixedRate(scala.concurrent.duration.FiniteDuration, scala.concurrent.duration.FiniteDuration, java.lang.Runnable, scala.concurrent.ExecutionContext).

Specified by:

schedule in interface Scheduler

scheduleOnce

public Cancellable scheduleOnce(scala.concurrent.duration.FiniteDuration delay,
                                java.lang.Runnable runnable,
                                scala.concurrent.ExecutionContext executor)

Description copied from interface: Scheduler

Scala API: Schedules a Runnable to be run once with a delay, i.e. a time period that has to pass before the runnable is executed.

Specified by:

scheduleOnce in interface Scheduler

close

public void close()

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

maxFrequency

public double maxFrequency()

Description copied from interface: Scheduler

The maximum supported task frequency of this scheduler, i.e. the inverse of the minimum time interval between executions of a recurring task, in Hz.

Specified by:

maxFrequency in interface Scheduler