Class MpUnboundedXaddArrayQueue<R extends MpUnboundedXaddChunk<R,E>, E>

java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractQueue<E>
org.jctools.queues.MpUnboundedXaddArrayQueuePad1<E>
org.jctools.queues.MpUnboundedXaddArrayQueueProducerFields<E>
org.jctools.queues.MpUnboundedXaddArrayQueuePad2<E>
org.jctools.queues.MpUnboundedXaddArrayQueueProducerChunk<R,E>
org.jctools.queues.MpUnboundedXaddArrayQueuePad3<R,E>
org.jctools.queues.MpUnboundedXaddArrayQueueConsumerFields<R,E>
org.jctools.queues.MpUnboundedXaddArrayQueuePad5<R,E>
org.jctools.queues.MpUnboundedXaddArrayQueue<R,E>
All Implemented Interfaces:
Iterable<E>, Collection<E>, Queue<E>, IndexedQueueSizeUtil.IndexedQueue, MessagePassingQueue<E>, QueueProgressIndicators
Direct Known Subclasses:
MpmcUnboundedXaddArrayQueue, MpscUnboundedXaddArrayQueue
abstract class MpUnboundedXaddArrayQueue<R extends MpUnboundedXaddChunk<R,E>, E> extends MpUnboundedXaddArrayQueuePad5<R,E> implements MessagePassingQueue<E>, QueueProgressIndicators
Common infrastructure for the XADD queues.

  • Field Details

  • Constructor Details

    • MpUnboundedXaddArrayQueue

      MpUnboundedXaddArrayQueue(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

  • Method Details

    • chunkSize

      public final int chunkSize()

    • maxPooledChunks

      public final int maxPooledChunks()

    • newChunk

      abstract R newChunk(long index, R prev, int chunkSize, boolean pooled)

    • 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

    • producerChunkForIndex

      final R producerChunkForIndex(R initialChunk, long requiredChunkIndex)
      We're here because currentChunk.index doesn't match the expectedChunkIndex. To resolve we must now chase the linked chunks to the appropriate chunk. More than one producer may end up racing to add or discover new chunks.
      Parameters:
      initialChunk - the starting point chunk, which does not match the required chunk index
      requiredChunkIndex - the chunk index we need
      Returns:
      the chunk matching the required index

    • appendNextChunks

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

    • newOrPooledChunk

      private R newOrPooledChunk(R prevChunk, long nextChunkIndex)

    • moveToNextConsumerChunk

      final void moveToNextConsumerChunk(R cChunk, R next)
      Does not null out the first element of `next`, callers must do that

    • iterator

      public Iterator<E> iterator()
      Specified by:
      iterator in interface Collection<R extends MpUnboundedXaddChunk<R,E>>
      Specified by:
      iterator in interface Iterable<R extends MpUnboundedXaddChunk<R,E>>
      Specified by:
      iterator in class AbstractCollection<E>

    • size

      public int size()
      Description copied from interface: MessagePassingQueue
      This method's accuracy is subject to concurrent modifications happening as the size is estimated and as such is a best effort rather than absolute value. For some implementations this method may be O(n) rather than O(1).
      Specified by:
      size in interface Collection<R extends MpUnboundedXaddChunk<R,E>>
      Specified by:
      size in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,E>>
      Specified by:
      size in class AbstractCollection<E>
      Returns:
      number of messages in the queue, between 0 and Integer.MAX_VALUE but less or equals to capacity (if bounded).

    • isEmpty

      public boolean isEmpty()
      Description copied from interface: MessagePassingQueue
      This method's accuracy is subject to concurrent modifications happening as the observation is carried out.
      Specified by:
      isEmpty in interface Collection<R extends MpUnboundedXaddChunk<R,E>>
      Specified by:
      isEmpty in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,E>>
      Overrides:
      isEmpty in class AbstractCollection<E>
      Returns:
      true if empty, false otherwise

    • capacity

      public int capacity()
      Specified by:
      capacity in interface IndexedQueueSizeUtil.IndexedQueue
      Specified by:
      capacity in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,E>>
      Returns:
      the capacity of this queue or MessagePassingQueue.UNBOUNDED_CAPACITY if not bounded

    • 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

    • drain

      public void drain(MessagePassingQueue.Consumer<E> c, MessagePassingQueue.WaitStrategy wait, MessagePassingQueue.ExitCondition exit)
      Description copied from interface: MessagePassingQueue
      Remove elements from the queue and hand to consume forever. Semantically similar to: 

       int idleCounter = 0;
 while (exit.keepRunning()) {
     E e = relaxedPoll();
     if(e==null){
         idleCounter = wait.idle(idleCounter);
         continue;
     }
     idleCounter = 0;
     c.accept(e);
 }

      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>>

    • fill

      public void fill(MessagePassingQueue.Supplier<E> s, MessagePassingQueue.WaitStrategy wait, MessagePassingQueue.ExitCondition exit)
      Description copied from interface: MessagePassingQueue
      Stuff the queue with elements from the supplier forever. Semantically similar to: 

      
 int idleCounter = 0;
 while (exit.keepRunning()) {
     E e = s.get();
     while (!relaxedOffer(e)) {
         idleCounter = wait.idle(idleCounter);
         continue;
     }
     idleCounter = 0;
 }

      Called from a producer thread subject to the restrictions appropriate to the implementation. The main difference being that implementors MUST assure room in the queue is available BEFORE calling MessagePassingQueue.Supplier.get(). 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>>

    • toString

      public String toString()
      Overrides:
      toString in class AbstractCollection<E>