protected virtual bool ReceiveElement(T message)
{
if (IsActive)
{
if (TotalDemand > 0L)
{
OnNext(message);
}
else if (BufferSize == 0)
{
Log.Debug("Dropping element because there is no downstream demand: [{0}]", message);
}
else if (!Buffer.IsFull)
{
Buffer.Enqueue(message);
}
else
{
switch (OverflowStrategy)
{
case OverflowStrategy.DropHead:
Log.Debug("Dropping the head element because buffer is full and overflowStrategy is: [DropHead]");
Buffer.DropHead();
Buffer.Enqueue(message);
break;
case OverflowStrategy.DropTail:
Log.Debug("Dropping the tail element because buffer is full and overflowStrategy is: [DropTail]");
Buffer.DropTail();
Buffer.Enqueue(message);
break;
case OverflowStrategy.DropBuffer:
Log.Debug("Dropping all the buffered elements because buffer is full and overflowStrategy is: [DropBuffer]");
Buffer.Clear();
Buffer.Enqueue(message);
break;
case OverflowStrategy.DropNew:
// do not enqueue new element if the buffer is full
Log.Debug("Dropping the new element because buffer is full and overflowStrategy is: [DropNew]");
break;
case OverflowStrategy.Fail:
Log.Error("Failing because buffer is full and overflowStrategy is: [Fail]");
OnErrorThenStop(new BufferOverflowException($"Buffer overflow, max capacity was ({BufferSize})"));
break;
case OverflowStrategy.Backpressure:
// there is a precondition check in Source.actorRefSource factory method
Log.Debug("Backpressuring because buffer is full and overflowStrategy is: [Backpressure]");
break;
}
}
return(true);
}
return(false);
}
private void BufferElement(Offer <TOut> offer)
{
if (!_buffer.IsFull)
{
EnqueueAndSuccess(offer);
}
else
{
switch (_stage._overflowStrategy)
{
case OverflowStrategy.DropHead:
_buffer.DropHead();
EnqueueAndSuccess(offer);
break;
case OverflowStrategy.DropTail:
_buffer.DropTail();
EnqueueAndSuccess(offer);
break;
case OverflowStrategy.DropBuffer:
_buffer.Clear();
EnqueueAndSuccess(offer);
break;
case OverflowStrategy.DropNew:
offer.CompletionSource.SetResult(QueueOfferResult.Dropped.Instance);
break;
case OverflowStrategy.Fail:
var bufferOverflowException =
new BufferOverflowException($"Buffer overflow (max capacity was: {_stage._maxBuffer})!");
offer.CompletionSource.SetResult(new QueueOfferResult.Failure(bufferOverflowException));
_completion.SetException(bufferOverflowException);
FailStage(bufferOverflowException);
break;
case OverflowStrategy.Backpressure:
if (_pendingOffer != null)
{
offer.CompletionSource.SetException(
new IllegalStateException(
"You have to wait for previous offer to be resolved to send another request."));
}
else
{
_pendingOffer = offer;
}
break;
}
}
}
/// <summary> /// TBD /// </summary> public void DropTail() => _q.DropTail();
