public static void SuspendResumeTrialFinal()
{
var scheduler = new TestScheduler();
int suspendOnCount = 3;
TimeSpan suspendCountDuration = TimeSpan.FromSeconds(5);
TimeSpan suspendDuration = TimeSpan.FromSeconds(15);
var subject = new Subject <int>();
var source = subject.Timestamp(scheduler).Select(i => new MetaValue <int>(i.Value, i.Timestamp, Emit.Value));
var head = source.Take(2);
var tail = source
.Buffer(3, 1)
.Where(b => b.Count == 3)
.Select(b =>
{
var lastInBuffer = b.Last();
var firstInBuffer = b.First();
var diff = lastInBuffer.Timestamp.Subtract(firstInBuffer.Timestamp);
return(new MetaValue <int>(lastInBuffer.Value, lastInBuffer.Timestamp, diff <= suspendCountDuration ? Emit.Suspend : Emit.Value));
});
var rectified = tail.Scan(
ScannedValueWithRectification <int> .Empty,
(enrichedAccumulatedValue, currentMetaValue) =>
{
if (enrichedAccumulatedValue.StartOfSuspendWindow != DateTimeOffset.MinValue)
{
var endOfSuspend = enrichedAccumulatedValue.StartOfSuspendWindow.Add(suspendDuration);
if (currentMetaValue.Timestamp < endOfSuspend)
{
return(new ScannedValueWithRectification <int>(
null,
enrichedAccumulatedValue.StartOfSuspendWindow,
enrichedAccumulatedValue.RemainingNumberOfValuesToRectify));
}
}
if (enrichedAccumulatedValue.RemainingNumberOfValuesToRectify > 0)
{
// Rectify the first N-1 values after a resume to Emit.Value
var rectifiedCurrent = new MetaValue <int>(currentMetaValue.Value, currentMetaValue.Timestamp, Emit.Value);
// Preserve the information of the suspend window until all necessary values have been rectified
return(new ScannedValueWithRectification <int>(
rectifiedCurrent,
enrichedAccumulatedValue.StartOfSuspendWindow,
enrichedAccumulatedValue.RemainingNumberOfValuesToRectify - 1));
}
return(currentMetaValue.Kind == Emit.Suspend
? new ScannedValueWithRectification <int>(null, currentMetaValue.Timestamp, 2)
: new ScannedValueWithRectification <int>(currentMetaValue, DateTimeOffset.MinValue, 0));
//Emit value
})
.Where(ev => ev.MetaValue != null)
.Select(ev => ev.MetaValue);
var prefinal = head.Merge(rectified);
prefinal.Subscribe(Console.WriteLine);
var final = prefinal.Select(m => m.Value);
/**********************************************************************
*
* source --1---------2----------3-4-5-6-7--------8---------9------
*
**********************************************************************/
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(2000).Ticks);
subject.OnNext(1);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(10000).Ticks);
subject.OnNext(2);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(11000).Ticks);
subject.OnNext(3);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(2000).Ticks);
subject.OnNext(4);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(1500).Ticks);
subject.OnNext(5);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(1250).Ticks);
subject.OnNext(6);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(2250).Ticks);
subject.OnNext(7);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(9000).Ticks);
subject.OnNext(8);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(10000).Ticks);
subject.OnNext(9);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(22000).Ticks);
subject.OnNext(10);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(2000).Ticks);
subject.OnNext(11);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(2000).Ticks);
subject.OnNext(12);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(12000).Ticks);
subject.OnNext(13);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(1000).Ticks);
subject.OnNext(14);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(2000).Ticks);
subject.OnNext(15); //should be emitted outside of suspend
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(1000).Ticks);
subject.OnNext(16);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(2000).Ticks);
subject.OnNext(17);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(10000).Ticks);
subject.OnNext(18);
scheduler.AdvanceBy(TimeSpan.FromMilliseconds(1).Ticks);
subject.OnCompleted();
}
public ScannedValue(MetaValue <T> metaValue, DateTimeOffset startOfSuspendWindow)
{
MetaValue = metaValue;
StartOfSuspendWindow = startOfSuspendWindow;
}
public static IObservable <T> SuspendDuringFloodWithRectification <T>(
this IObservable <T> source,
int maxElementsPerWindow,
TimeSpan windowDuration,
TimeSpan suspendDuration,
IScheduler scheduler)
{
scheduler = scheduler ?? new TestScheduler();
var internalSource = source.Timestamp(scheduler).Select(i => new MetaValue <T>(i.Value, i.Timestamp, Emit.Value));
// The first max-1 elements will always be emitted (no need to enrich them)
var head = source.Take(maxElementsPerWindow - 1);
// Enrich the rest of the elements with information about the absolute time they were emitted (see ... below)
var tail = internalSource
// Apply a buffer in order to determine if the last element in the buffer (the element of importance) is supposed to introduce a suspension
.Buffer(maxElementsPerWindow, 1)
// The last max-1 buffers are incomplete and can be safely ignored, because the last buffer of size max contains that last element in the observable
.Where(b => b.Count == maxElementsPerWindow)
.Select(b =>
{
var lastInBuffer = b.Last();
var firstInBuffer = b.First();
var diff = lastInBuffer.Timestamp.Subtract(firstInBuffer.Timestamp);
//... also enrich the value with information about whether or not it is supposed to introduce a suspension
// (based on the time difference to the first element in the buffer)
return(new MetaValue <T>(lastInBuffer.Value, lastInBuffer.Timestamp, diff <= windowDuration ? Emit.Suspend : Emit.Value));
});
// Run through the meta values produced and ignore the ones emitted during a suspend,
// while rectifing (emitting) the ones wrongly identified as suspended (caused by them being in buffers with values that should have been ignored)
var rectifiedTail = tail.Scan(
ScannedValueWithRectification <T> .Empty,
(accumulator, metaValue) =>
{
if (accumulator.StartOfSuspendWindow != DateTimeOffset.MinValue)
{
var endOfSuspend = accumulator.StartOfSuspendWindow.Add(suspendDuration);
if (metaValue.Timestamp < endOfSuspend) // Ignore (return null) values emitted during an ongoing suspend window
{
return(new ScannedValueWithRectification <T>(
null,
accumulator.StartOfSuspendWindow,
accumulator.RemainingNumberOfValuesToRectify));
}
}
if (accumulator.RemainingNumberOfValuesToRectify > 0)
{
// Rectify the first max-1 values after a resume to Emit.Value. There is a philosofical reason for this: if one value
// (for which there is always a buffer in which it is the last value) is deemed as introducing a suspension due
// to values from the original source that ended up being ignored because they were emitted during an active suspension,
// I don't find it logical for this value to still be considered as introducing a suspension. It should be considered as
// the 1st value emitted after a suspend, and because suspendDuration >> windowDuration it should always emit a value, same goes
// for all max-1 values that follow an end of a suspension interval.
var rectifiedCurrent = new MetaValue <T>(metaValue.Value, metaValue.Timestamp, Emit.Value);
// Preserve the information of the suspend window until all necessary values have been rectified
return(new ScannedValueWithRectification <T>(
rectifiedCurrent,
accumulator.StartOfSuspendWindow,
accumulator.RemainingNumberOfValuesToRectify - 1));
}
return(metaValue.Kind == Emit.Suspend
? new ScannedValueWithRectification <T>(null, metaValue.Timestamp, maxElementsPerWindow - 1) // Begin a suspend window without emitting the value that triggered it
: new ScannedValueWithRectification <T>(metaValue, DateTimeOffset.MinValue, 0)); // Emit a value
})
.Where(sv => sv.MetaValue != null) // This is the part that effectively actually ignores the values under a suspend window
.Select(ev => ev.MetaValue.Value);
return(head.Merge(rectifiedTail));
}
public ScannedValueWithRectification(MetaValue <T> metaValue, DateTimeOffset startOfSuspendWindow, int remainingNumberOfValuesToRectify)
: base(metaValue, startOfSuspendWindow)
{
RemainingNumberOfValuesToRectify = remainingNumberOfValuesToRectify;
}
