Package org.jctools.queues

Class MpmcUnboundedXaddArrayQueue<E>

    • Constructor Detail

      • MpmcUnboundedXaddArrayQueue

        public MpmcUnboundedXaddArrayQueue​(int chunkSize,
                                   int maxPooledChunks)
        Parameters:
        chunkSize - The buffer size to be used in each chunk of this queue
        maxPooledChunks - The maximum number of reused chunks kept around to avoid allocation, chunks are pre-allocated

      • MpmcUnboundedXaddArrayQueue

        public MpmcUnboundedXaddArrayQueue​(int chunkSize)

    • Method Detail

      • offer

        public boolean offer​(E e)
        Description copied from interface: MessagePassingQueue
        Called from a producer thread subject to the restrictions appropriate to the implementation and according to the Queue.offer(Object) interface.
        Parameters:
        e - not null, will throw NPE if it is
        Returns:
        true if element was inserted into the queue, false iff full

      • poll

        public E poll()
        Description copied from interface: MessagePassingQueue
        Called from the consumer thread subject to the restrictions appropriate to the implementation and according to the Queue.poll() interface.
        Returns:
        a message from the queue if one is available, null iff empty

      • peek

        public E peek()
        Description copied from interface: MessagePassingQueue
        Called from the consumer thread subject to the restrictions appropriate to the implementation and according to the Queue.peek() interface.
        Returns:
        a message from the queue if one is available, null iff empty

      • relaxedPoll

        public E relaxedPoll()
        Description copied from interface: MessagePassingQueue
        Called from the consumer thread subject to the restrictions appropriate to the implementation. As opposed to Queue.poll() this method may return null without the queue being empty.
        Returns:
        a message from the queue if one is available, null if unable to poll

      • relaxedPeek

        public E relaxedPeek()
        Description copied from interface: MessagePassingQueue
        Called from the consumer thread subject to the restrictions appropriate to the implementation. As opposed to Queue.peek() this method may return null without the queue being empty.
        Returns:
        a message from the queue if one is available, null if unable to peek

      • fill

        public int fill​(MessagePassingQueue.Supplier<E> s,
                int limit)
        Description copied from interface: MessagePassingQueue
        Stuff the queue with up to limit elements from the supplier. Semantically similar to: 

        
   for(int i=0; i < limit && relaxedOffer(s.get()); i++);

        There's no strong commitment to the queue being full at the end of a fill. Called from a producer thread subject to the restrictions appropriate to the implementation. WARNING: Explicit assumptions are made with regards to MessagePassingQueue.Supplier.get() make sure you have read and understood these before using this method.

        Returns:
        the number of offered elements

      • chunkSize

        public final int chunkSize()

      • maxPooledChunks

        public final int maxPooledChunks()

      • currentProducerIndex

        public long currentProducerIndex()
        Description copied from interface: QueueProgressIndicators
        This method has no concurrent visibility semantics. The value returned may be negative. Under normal circumstances 2 consecutive calls to this method can offer an idea of progress made by producer threads by subtracting the 2 results though in extreme cases (if producers have progressed by more than 2^64) this may also fail.
        This value will normally indicate number of elements passed into the queue, but may under some circumstances be a derivative of that figure. This method should not be used to derive size or emptiness.
        Specified by:
        currentProducerIndex in interface QueueProgressIndicators
        Returns:
        the current value of the producer progress index

      • currentConsumerIndex

        public long currentConsumerIndex()
        Description copied from interface: QueueProgressIndicators
        This method has no concurrent visibility semantics. The value returned may be negative. Under normal circumstances 2 consecutive calls to this method can offer an idea of progress made by consumer threads by subtracting the 2 results though in extreme cases (if consumers have progressed by more than 2^64) this may also fail.
        This value will normally indicate number of elements taken out of the queue, but may under some circumstances be a derivative of that figure. This method should not be used to derive size or emptiness.
        Specified by:
        currentConsumerIndex in interface QueueProgressIndicators
        Returns:
        the current value of the consumer progress index

      • appendNextChunks

        protected final R appendNextChunks​(R currentChunk,
                                   long currentChunkIndex,
                                   long chunksToAppend)

      • relaxedOffer

        public boolean relaxedOffer​(E e)
        Description copied from interface: MessagePassingQueue
        Called from a producer thread subject to the restrictions appropriate to the implementation. As opposed to Queue.offer(Object) this method may return false without the queue being full.
        Specified by:
        relaxedOffer in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Parameters:
        e - not null, will throw NPE if it is
        Returns:
        true if element was inserted into the queue, false if unable to offer

      • drain

        public int drain​(MessagePassingQueue.Consumer<E> c)
        Description copied from interface: MessagePassingQueue
        Remove all available item from the queue and hand to consume. This should be semantically similar to: 
         M m;
 while((m = relaxedPoll()) != null){
 c.accept(m);
 }
        There's no strong commitment to the queue being empty at the end of a drain. Called from a consumer thread subject to the restrictions appropriate to the implementation.

        WARNING: Explicit assumptions are made with regards to MessagePassingQueue.Consumer.accept(T) make sure you have read and understood these before using this method.

        Specified by:
        drain in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Returns:
        the number of polled elements

      • fill

        public int fill​(MessagePassingQueue.Supplier<E> s)
        Description copied from interface: MessagePassingQueue
        Stuff the queue with elements from the supplier. Semantically similar to: 
         while(relaxedOffer(s.get());
        There's no strong commitment to the queue being full at the end of a fill. Called from a producer thread subject to the restrictions appropriate to the implementation.

        Unbounded queues will fill up the queue with a fixed amount rather than fill up to oblivion. WARNING: Explicit assumptions are made with regards to MessagePassingQueue.Supplier.get() make sure you have read and understood these before using this method.

        Specified by:
        fill in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Returns:
        the number of offered elements

      • drain

        public int drain​(MessagePassingQueue.Consumer<E> c,
                 int limit)
        Description copied from interface: MessagePassingQueue
        Remove up to limit elements from the queue and hand to consume. This should be semantically similar to: 

        
   M m;
   int i = 0;
   for(;i < limit && (m = relaxedPoll()) != null; i++){
     c.accept(m);
   }
   return i;

        There's no strong commitment to the queue being empty at the end of a drain. Called from a consumer thread subject to the restrictions appropriate to the implementation.

        WARNING: Explicit assumptions are made with regards to MessagePassingQueue.Consumer.accept(T) make sure you have read and understood these before using this method.

        Specified by:
        drain in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Returns:
        the number of polled elements

      • lvConsumerIndex

        public final long lvConsumerIndex()

      • lvProducerIndex

        public final long lvProducerIndex()