Package org.apache.pekko.actor

Class TimerScheduler

java.lang.Object
org.apache.pekko.actor.TimerScheduler
public abstract class TimerScheduler extends Object
Support for scheduled self messages in an actor. It is used by mixing in trait Timers in Scala or extending AbstractActorWithTimers in Java.

Timers are bound to the lifecycle of the actor that owns it, and thus are cancelled automatically when it is restarted or stopped.

TimerScheduler is not thread-safe, i.e. it must only be used within the actor that owns it.

  • Constructor Summary

    Constructors
    Constructor
    Description
    TimerScheduler()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    abstract void
    cancel(Object key)
    Cancel a timer with a given key.
    abstract void
    cancelAll()
    Cancel all timers.
    abstract boolean
    isTimerActive(Object key)
    Check if a timer with a given key is active.
    final void
    startSingleTimer(Object key, Object msg, Duration timeout)
    Start a timer that will send msg once to the self actor after the given timeout.
    abstract void
    startSingleTimer(Object key, Object msg, scala.concurrent.duration.FiniteDuration timeout)
    Start a timer that will send msg once to the self actor after the given timeout.
    final void
    startTimerAtFixedRate(Object key, Object msg, Duration interval)
    Java API: Schedules a message to be sent repeatedly to the self actor with a given frequency.
    final void
    startTimerAtFixedRate(Object key, Object msg, Duration initialDelay, Duration interval)
    Java API: Schedules a message to be sent repeatedly to the self actor with a given frequency.
    abstract void
    startTimerAtFixedRate(Object key, Object msg, scala.concurrent.duration.FiniteDuration interval)
    Scala API: Schedules a message to be sent repeatedly to the self actor with a given frequency.
    abstract void
    startTimerAtFixedRate(Object key, Object msg, scala.concurrent.duration.FiniteDuration initialDelay, scala.concurrent.duration.FiniteDuration interval)
    Scala API: Schedules a message to be sent repeatedly to the self actor with a given frequency.
    final void
    startTimerWithFixedDelay(Object key, Object msg, Duration delay)
    Java API: Schedules a message to be sent repeatedly to the self actor with a fixed delay between messages.
    final void
    startTimerWithFixedDelay(Object key, Object msg, Duration initialDelay, Duration delay)
    Java API: Schedules a message to be sent repeatedly to the self actor with a fixed delay between messages after the initialDelay.
    abstract void
    startTimerWithFixedDelay(Object key, Object msg, scala.concurrent.duration.FiniteDuration delay)
    Scala API: Schedules a message to be sent repeatedly to the self actor with a fixed delay between messages.
    abstract void
    startTimerWithFixedDelay(Object key, Object msg, scala.concurrent.duration.FiniteDuration initialDelay, scala.concurrent.duration.FiniteDuration delay)
    Scala API: Schedules a message to be sent repeatedly to the self actor with a fixed delay between messages after the initialDelay.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • TimerScheduler

      public TimerScheduler()

  • Method Details

    • cancel

      public abstract void cancel(Object key)
      Cancel a timer with a given key. If canceling a timer that was already canceled, or key never was used to start a timer this operation will do nothing.

      It is guaranteed that a message from a canceled timer, including its previous incarnation for the same key, will not be received by the actor, even though the message might already be enqueued in the mailbox when cancel is called.

    • cancelAll

      public abstract void cancelAll()
      Cancel all timers.

    • isTimerActive

      public abstract boolean isTimerActive(Object key)
      Check if a timer with a given key is active.

    • startSingleTimer

      public abstract void startSingleTimer(Object key, Object msg, scala.concurrent.duration.FiniteDuration timeout)
      Start a timer that will send msg once to the self actor after the given timeout.

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.

    • startSingleTimer

      public final void startSingleTimer(Object key, Object msg, Duration timeout)
      Start a timer that will send msg once to the self actor after the given timeout.

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.

    • startTimerAtFixedRate

      public abstract void startTimerAtFixedRate(Object key, Object msg, scala.concurrent.duration.FiniteDuration interval)
      Scala API: Schedules a message to be sent repeatedly to the self actor with a given frequency.

      It will compensate the delay for a subsequent message if the sending of previous message was delayed more than specified. In such cases, the actual message interval will differ from the interval passed to the method.

      If the execution is delayed longer than the interval, the subsequent message will be sent immediately after the prior one. This also has the consequence that after long garbage collection pauses or other reasons when the JVM was suspended all "missed" messages will be sent when the process wakes up again.

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

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

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.

    • startTimerAtFixedRate

      public abstract void startTimerAtFixedRate(Object key, Object msg, scala.concurrent.duration.FiniteDuration initialDelay, scala.concurrent.duration.FiniteDuration interval)
      Scala API: Schedules a message to be sent repeatedly to the self actor with a given frequency.

      It will compensate the delay for a subsequent message if the sending of previous message was delayed more than specified. In such cases, the actual message interval will differ from the interval passed to the method.

      If the execution is delayed longer than the interval, the subsequent message will be sent immediately after the prior one. This also has the consequence that after long garbage collection pauses or other reasons when the JVM was suspended all "missed" messages will be sent when the process wakes up again.

      In the long run, the frequency of messages will be exactly the reciprocal of the specified interval after initialDelay.

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

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.

    • startTimerAtFixedRate

      public final void startTimerAtFixedRate(Object key, Object msg, Duration interval)
      Java API: Schedules a message to be sent repeatedly to the self actor with a given frequency.

      It will compensate the delay for a subsequent message if the sending of previous message was delayed more than specified. In such cases, the actual message interval will differ from the interval passed to the method.

      If the execution is delayed longer than the interval, the subsequent message will be sent immediately after the prior one. This also has the consequence that after long garbage collection pauses or other reasons when the JVM was suspended all "missed" messages will be sent when the process wakes up again.

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

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

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.

    • startTimerAtFixedRate

      public final void startTimerAtFixedRate(Object key, Object msg, Duration initialDelay, Duration interval)
      Java API: Schedules a message to be sent repeatedly to the self actor with a given frequency.

      It will compensate the delay for a subsequent message if the sending of previous message was delayed more than specified. In such cases, the actual message interval will differ from the interval passed to the method.

      If the execution is delayed longer than the interval, the subsequent message will be sent immediately after the prior one. This also has the consequence that after long garbage collection pauses or other reasons when the JVM was suspended all "missed" messages will be sent when the process wakes up again.

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

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

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.

    • startTimerWithFixedDelay

      public abstract void startTimerWithFixedDelay(Object key, Object msg, scala.concurrent.duration.FiniteDuration delay)
      Scala API: Schedules a message to be sent repeatedly to the self actor with a fixed delay between messages.

      It will not compensate the delay between messages if scheduling is delayed longer than specified for some reason. The delay between sending of subsequent messages will always be (at least) the given delay.

      In the long run, the frequency of messages will generally be slightly lower than the reciprocal of the specified delay.

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.

    • startTimerWithFixedDelay

      public abstract void startTimerWithFixedDelay(Object key, Object msg, scala.concurrent.duration.FiniteDuration initialDelay, scala.concurrent.duration.FiniteDuration delay)
      Scala API: Schedules a message to be sent repeatedly to the self actor with a fixed delay between messages after the initialDelay.

      It will not compensate the delay between messages if scheduling is delayed longer than specified for some reason. The delay between sending of subsequent messages will always be (at least) the given delay.

      In the long run, the frequency of messages will generally be slightly lower than the reciprocal of the specified delay.

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.

    • startTimerWithFixedDelay

      public final void startTimerWithFixedDelay(Object key, Object msg, Duration delay)
      Java API: Schedules a message to be sent repeatedly to the self actor with a fixed delay between messages.

      It will not compensate the delay between messages if scheduling is delayed longer than specified for some reason. The delay between sending of subsequent messages will always be (at least) the given delay.

      In the long run, the frequency of messages will generally be slightly lower than the reciprocal of the specified delay.

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.

    • startTimerWithFixedDelay

      public final void startTimerWithFixedDelay(Object key, Object msg, Duration initialDelay, Duration delay)
      Java API: Schedules a message to be sent repeatedly to the self actor with a fixed delay between messages after the initialDelay.

      It will not compensate the delay between messages if scheduling is delayed longer than specified for some reason. The delay between sending of subsequent messages will always be (at least) the given delay.

      In the long run, the frequency of messages will generally be slightly lower than the reciprocal of the specified delay.

      Each timer has a key and if a new timer with same key is started the previous is cancelled. It is guaranteed that a message from the previous timer is not received, even if it was already enqueued in the mailbox when the new timer was started.