Class SleepingWaitStrategy

  • All Implemented Interfaces:
    WaitStrategy

    public final class SleepingWaitStrategy
    extends java.lang.Object
    implements WaitStrategy
    Sleeping strategy that initially spins, then uses a Thread.yield(), and eventually sleep (LockSupport.parkNanos(n)) for the minimum number of nanos the OS and JVM will allow while the EventProcessors are waiting on a barrier.

    This strategy is a good compromise between performance and CPU resource. Latency spikes can occur after quiet periods. It will also reduce the impact on the producing thread as it will not need signal any conditional variables to wake up the event handling thread.

    • Field Detail

      • retries

        private final int retries
      • sleepTimeNs

        private final long sleepTimeNs
    • Constructor Detail

      • SleepingWaitStrategy

        public SleepingWaitStrategy()
      • SleepingWaitStrategy

        public SleepingWaitStrategy​(int retries)
      • SleepingWaitStrategy

        public SleepingWaitStrategy​(int retries,
                                    long sleepTimeNs)
    • Method Detail

      • waitFor

        public long waitFor​(long sequence,
                            Sequence cursor,
                            Sequence dependentSequence,
                            SequenceBarrier barrier)
                     throws AlertException
        Description copied from interface: WaitStrategy
        Wait for the given sequence to be available. It is possible for this method to return a value less than the sequence number supplied depending on the implementation of the WaitStrategy. A common use for this is to signal a timeout. Any EventProcessor that is using a WaitStrategy to get notifications about message becoming available should remember to handle this case. The BatchEventProcessor explicitly handles this case and will signal a timeout if required.
        Specified by:
        waitFor in interface WaitStrategy
        Parameters:
        sequence - to be waited on.
        cursor - the main sequence from ringbuffer. Wait/notify strategies will need this as it's the only sequence that is also notified upon update.
        dependentSequence - on which to wait.
        barrier - the processor is waiting on.
        Returns:
        the sequence that is available which may be greater than the requested sequence.
        Throws:
        AlertException - if the status of the Disruptor has changed.