Package org.apache.pekko.actor.typed

Interface Scheduler

public interface Scheduler

The ActorSystem facility for scheduling tasks.

For scheduling within actors Behaviors.withTimers should be preferred.

Not for user extension

Method Summary

Modifier and Type	Method	Description
Cancellable	scheduleAtFixedRate(java.time.Duration initialDelay, java.time.Duration interval, java.lang.Runnable runnable, scala.concurrent.ExecutionContext executor)	Java API: Schedules a Runnable to be run repeatedly with an initial delay and a frequency.
Cancellable	scheduleAtFixedRate(scala.concurrent.duration.FiniteDuration initialDelay, scala.concurrent.duration.FiniteDuration interval, java.lang.Runnable runnable, scala.concurrent.ExecutionContext executor)	Scala API: Schedules a Runnable to be run repeatedly with an initial delay and a frequency.
Cancellable	scheduleOnce(java.time.Duration delay, java.lang.Runnable runnable, scala.concurrent.ExecutionContext executor)	Java API: Schedules a Runnable to be run once with a delay, i.e.
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(java.time.Duration initialDelay, java.time.Duration delay, java.lang.Runnable runnable, scala.concurrent.ExecutionContext executor)	Java API: Schedules a Runnable to be run repeatedly with an initial delay and a fixed delay between subsequent executions.
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.

Method Detail

scheduleAtFixedRate

Cancellable scheduleAtFixedRate(scala.concurrent.duration.FiniteDuration initialDelay,
                                scala.concurrent.duration.FiniteDuration interval,
                                java.lang.Runnable runnable,
                                scala.concurrent.ExecutionContext executor)

Scala API: Schedules a Runnable to be run repeatedly with an initial delay and a frequency. 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 compensate the delay for a subsequent task if the previous tasks took too long to execute. In such cases, the actual execution interval will differ from the interval passed to the method.

If the execution of the tasks takes longer than the interval, the subsequent execution will start immediately after the prior one completes (there will be no overlap of executions). This also has the consequence that after long garbage collection pauses or other reasons when the JVM was suspended all "missed" tasks will execute when the process wakes up again.

In the long run, the frequency of execution will be exactly the reciprocal of the specified interval.

Warning: scheduleAtFixedRate can result in bursts of scheduled tasks after long garbage collection pauses, which may in worst case cause undesired load on the system. Therefore scheduleWithFixedDelay is often preferred.

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

Throws:

java.lang.IllegalArgumentException - if the given delays exceed the maximum reach (calculated as: delay / tickNanos > Int.MaxValue).

Note: For scheduling within actors Behaviors.withTimers should be preferred.

scheduleAtFixedRate

Cancellable scheduleAtFixedRate(java.time.Duration initialDelay,
                                java.time.Duration interval,
                                java.lang.Runnable runnable,
                                scala.concurrent.ExecutionContext executor)

Java API: Schedules a Runnable to be run repeatedly with an initial delay and a frequency. E.g. if you would like the function to be run after 2 seconds and thereafter every 100ms you would set delay to Duration.ofSeconds(2), and interval to Duration.ofMillis(100).

It will compensate the delay for a subsequent task if the previous tasks took too long to execute. In such cases, the actual execution interval will differ from the interval passed to the method.

If the execution of the tasks takes longer than the interval, the subsequent execution will start immediately after the prior one completes (there will be no overlap of executions). This also has the consequence that after long garbage collection pauses or other reasons when the JVM was suspended all "missed" tasks will execute when the process wakes up again.

In the long run, the frequency of execution will be exactly the reciprocal of the specified interval.

Warning: scheduleAtFixedRate can result in bursts of scheduled tasks after long garbage collection pauses, which may in worst case cause undesired load on the system. Therefore scheduleWithFixedDelay is often preferred.

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

Throws:

java.lang.IllegalArgumentException - if the given delays exceed the maximum reach (calculated as: delay / tickNanos > Int.MaxValue).

Note: For scheduling in actors Behaviors.withTimers should be preferred.

scheduleOnce

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. a time period that has to pass before the runnable is executed.

Throws:

java.lang.IllegalArgumentException - if the given delays exceed the maximum reach (calculated as: delay / tickNanos > Int.MaxValue).

Note: For scheduling within actors Behaviors.withTimers or ActorContext.scheduleOnce should be preferred.

scheduleOnce

Cancellable scheduleOnce(java.time.Duration delay,
                         java.lang.Runnable runnable,
                         scala.concurrent.ExecutionContext executor)

Java 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.

Throws:

java.lang.IllegalArgumentException - if the given delays exceed the maximum reach (calculated as: delay / tickNanos > Int.MaxValue).

Note: For scheduling within actors Behaviors.withTimers or ActorContext.scheduleOnce should be preferred.

scheduleWithFixedDelay

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. 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.

Throws:

java.lang.IllegalArgumentException - if the given delays exceed the maximum reach (calculated as: delay / tickNanos > Int.MaxValue).

Note: For scheduling within actors Behaviors.withTimers should be preferred.

scheduleWithFixedDelay

Cancellable scheduleWithFixedDelay(java.time.Duration initialDelay,
                                   java.time.Duration delay,
                                   java.lang.Runnable runnable,
                                   scala.concurrent.ExecutionContext executor)

Java 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 to Duration.ofSeconds(2), and interval to Duration.ofMillis(100).

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 tasks 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.

Throws:

java.lang.IllegalArgumentException - if the given delays exceed the maximum reach (calculated as: delay / tickNanos > Int.MaxValue).

Note: For scheduling in actors Behaviors.withTimers should be preferred.