public MockDataService()
{
// Simulate Http response pipeline.
IObservable <List <Item> > responseStream = Observable.Interval(TimeSpan.FromSeconds(1))
.Take(50)
.LogConsoleWithThread("Interval")
.Select(tick =>
{
// New Item appears on the stream every 5 ticks.
// Items last for 10 ticks. Item Value has range (0-9)
int rangeStart = Math.Max(((int)tick / 5) - 1, 0);
int rangeCount = Math.Min(((int)tick / 5) + 1, 2);
return(Enumerable.Range(rangeStart, rangeCount).Select(id => new Item(id, (int)tick - (id * 5))).ToList());
});
// Flatten the list into IObservable<Item>
var itemStream = responseStream
.SelectMany(list => list)
.LogConsoleWithThread("ItemStream");
// Split into groups by Item.Id and process each group for changes
// ChangeStream is an IObservable<Item> of changes.
_changeStream = itemStream
.GroupBy(item => item.Id)
.SelectMany(grp =>
grp
// Pipeline for each group.
.StartWith(new Item(grp.Key, -1))
.TakeUntil(item => item.Value >= 9)
.LogConsoleWithThread($"Group: {grp.Key}")
.Buffer(2, 1)
.Where(buffer => buffer.Count == 2 && buffer[0].HasChanges(buffer[1]))
.Select(buffer => buffer[1])
.LogConsoleWithThread($"Group.Change : {grp.Key}")
)
.Publish();
_replayChangeStream = _changeStream
.Multicast(new ReplayLastPerKeySubject <Item, int>(x => x.Id))
.RefCount();
}