static void RunQuery(NorthwindEntities northwind, Application application)
{
// Issue OData queries to determine start and end times for orders.
// So that the sources behave like temporal streams, we order by the
// corresponding dates.
var ordersWithRegions =
from o in northwind.Orders
where o.ShipRegion != null
select o;
var orderStartTimes =
from o in ordersWithRegions
where o.OrderDate != null
orderby o.OrderDate
select new { StartTime = (DateTime)o.OrderDate, o.OrderID, o.ShipRegion };
var orderEndTimes =
from o in ordersWithRegions
where o.ShippedDate != null
orderby o.ShippedDate
select new { EndTime = (DateTime)o.ShippedDate, o.OrderID };
// Map OData queries to StreamInsight inputs
var startStream = orderStartTimes.ToPointStream(application, s =>
PointEvent.CreateInsert(s.StartTime, s), AdvanceTimeSettings.IncreasingStartTime);
var endStream = orderEndTimes.ToPointStream(application, e =>
PointEvent.CreateInsert(e.EndTime, e), AdvanceTimeSettings.IncreasingStartTime);
// Use clip to synthesize events lasting from the start of each order to the end
// of each order.
var clippedStream = startStream
.AlterEventDuration(e => TimeSpan.MaxValue)
.ClipEventDuration(endStream, (s, e) => s.OrderID == e.OrderID);
// Count the number of coincident orders per region
var counts = from o in clippedStream
group o by o.ShipRegion into g
from win in g.SnapshotWindow(SnapshotWindowOutputPolicy.Clip)
select new { ShipRegion = g.Key, Count = win.Count() };
// Display output whenever there are more than 2 active orders in a region.
const int threshold = 2;
var query = from c in counts
where c.Count > threshold
select c;
// Map the query to an IEnumerable sink
var sink = from i in query.ToIntervalEnumerable()
where i.EventKind == EventKind.Insert
select new { i.StartTime, i.EndTime, i.Payload.Count, i.Payload.ShipRegion };
foreach (var r in sink)
{
Console.WriteLine(r);
}
}
static void Main(string[] args)
{
NorthwindEntities northwind = new NorthwindEntities(
new Uri("http://services.odata.org/Northwind/Northwind.svc"));
using (Server server = Server.Create("Default"))
{
Application application = server.CreateApplication("app");
RunQuery(northwind, application);
}
}
