Hot path SPSC LAQ

SpscLAQ.java

@Override
public boolean offer(final E e) {
  Objects.requireNonNull(e);
  
  // local load of fields to avoid repeated loads after volatile reads
  final E[] buffer = producerBuffer;
  final long index = producerIndex;
  final long mask = producerMask;
  final long offset = calcElementOffset(index, mask);

  // expected hot path
  if (index < producerBufferLimit) {
    writeToQueue(buffer, e, index, offset);
    return true;
  }

  return offerColdPath(buffer, mask, e, index, offset);
}

protected final void writeToQueue(final E[] buffer, final E e, final long index, final long offset) {
  soElement(buffer, offset, e); // ordered: buffer[index&mask] = e;
  soProducerIndex(index + 1); // ordered: producerIndex = index + 1;
}

@Override
public E poll() {
  // local load of fields to avoid repeated loads after volatile reads
  final E[] buffer = consumerBuffer;
  final long index = consumerIndex;
  final long mask = consumerMask;
  final long offset = calcElementOffset(index, mask);
  final Object e = lvElement(buffer, offset); // volatile: e = buffer[index&mask];

  final boolean jumpToNextBuffer = (e == JUMP);
  if (null != e && !jumpToNextBuffer) {
    soConsumerIndex(index + 1); // ordered: consumerIndex = index + 1;
    soElement(buffer, offset, null); // oredered: buffer[index&mask] = null;
    return (E) e;
  }
  else if (jumpToNextBuffer) {
    return newBufferPoll(buffer, index);
  }

  return null;
}