Class BackpressureDrainManager

  • All Implemented Interfaces:
    java.io.Serializable, Producer

    @Experimental
    public final class BackpressureDrainManager
    extends java.util.concurrent.atomic.AtomicLong
    implements Producer
    Manages the producer-backpressure-consumer interplay by matching up available elements with requested elements and/or terminal events.
    Since:
    1.1.0
    See Also:
    Serialized Form
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void drain()
      Try to drain the "queued" elements and terminal events by considering the available and requested event counts.
      boolean isTerminated()
      Checks if a terminal state has been reached.
      void request​(long n)
      Request a certain maximum number of items from this Producer.
      void terminate()
      Move into a terminal state.
      void terminate​(java.lang.Throwable error)
      Move into a terminal state with an exception.
      void terminateAndDrain()
      Move into a terminal state and drain.
      void terminateAndDrain​(java.lang.Throwable error)
      Move into a terminal state with an exception and drain.
      • Methods inherited from class java.util.concurrent.atomic.AtomicLong

        accumulateAndGet, addAndGet, compareAndExchange, compareAndExchangeAcquire, compareAndExchangeRelease, compareAndSet, decrementAndGet, doubleValue, floatValue, get, getAcquire, getAndAccumulate, getAndAdd, getAndDecrement, getAndIncrement, getAndSet, getAndUpdate, getOpaque, getPlain, incrementAndGet, intValue, lazySet, longValue, set, setOpaque, setPlain, setRelease, toString, updateAndGet, weakCompareAndSet, weakCompareAndSetAcquire, weakCompareAndSetPlain, weakCompareAndSetRelease, weakCompareAndSetVolatile
      • Methods inherited from class java.lang.Number

        byteValue, shortValue
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Field Detail

      • emitting

        boolean emitting
        Indicates if one is in emitting phase, guarded by this.
      • terminated

        volatile boolean terminated
        Indicates a terminal state.
      • exception

        java.lang.Throwable exception
        Indicates an error state, barrier is provided via terminated.
    • Constructor Detail

      • BackpressureDrainManager

        public BackpressureDrainManager​(BackpressureDrainManager.BackpressureQueueCallback actual)
        Constructs a backpressure drain manager with 0 requestedCount, no terminal event and not emitting.
        Parameters:
        actual - he queue callback to check for new element availability
    • Method Detail

      • isTerminated

        public boolean isTerminated()
        Checks if a terminal state has been reached.
        Returns:
        true if a terminal state has been reached
      • terminate

        public void terminate()
        Move into a terminal state. Call drain() anytime after.
      • terminate

        public void terminate​(java.lang.Throwable error)
        Move into a terminal state with an exception. Call drain() anytime after.

        Serialized access is expected with respect to element emission.

        Parameters:
        error - the exception to deliver
      • terminateAndDrain

        public void terminateAndDrain()
        Move into a terminal state and drain.
      • terminateAndDrain

        public void terminateAndDrain​(java.lang.Throwable error)
        Move into a terminal state with an exception and drain.

        Serialized access is expected with respect to element emission.

        Parameters:
        error - the exception to deliver
      • request

        public void request​(long n)
        Description copied from interface: Producer
        Request a certain maximum number of items from this Producer. This is a way of requesting backpressure. To disable backpressure, pass Long.MAX_VALUE to this method.

        Requests are additive but if a sequence of requests totals more than Long.MAX_VALUE then Long.MAX_VALUE requests will be actioned and the extras may be ignored. Arriving at Long.MAX_VALUE by addition of requests cannot be assumed to disable backpressure. For example, the code below may result in Long.MAX_VALUE requests being actioned only.

         request(100);
         request(Long.MAX_VALUE-1);
         
        Specified by:
        request in interface Producer
        Parameters:
        n - the maximum number of items you want this Producer to produce, or Long.MAX_VALUE if you want the Producer to produce items at its own pace
      • drain

        public void drain()
        Try to drain the "queued" elements and terminal events by considering the available and requested event counts.