CepStream.IsEmpty<TPayload> Method
Function used in queries to indicate a left anti-semi-join (LASJ).
Namespace: Microsoft.ComplexEventProcessing.Linq
Assembly: Microsoft.ComplexEventProcessing (in Microsoft.ComplexEventProcessing.dll)
Syntax
public static bool IsEmpty<TPayload>(
this CepStream<TPayload> source
)
Type Parameters
- TPayload
Input event payload type.
Parameters
- source
Type: Microsoft.ComplexEventProcessing.Linq.CepStream<TPayload>
Input stream.
Return Value
Type: System.Boolean
A new stream with the events' time changed.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type CepStream<TPayload>. When you use instance method syntax to call this method, omit the first parameter. For more information, see https://msdn.microsoft.com/en-us/library/bb384936(v=sql.105) or https://msdn.microsoft.com/en-us/library/bb383977(v=sql.105).
Remarks
For more information, see Joins.
Examples
The left anti-semi-join produces a join result for each event on the left side only if the result of the ordinary join is empty, for each point in time. This operation is useful to detect gaps with zero events.
var leftAntiSemiJoin = from left in stream1
where (from right in stream2
where left.v == right.v
select right).IsEmpty()
select left;