Share via


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

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;

See Also

Reference

CepStream Class

Microsoft.ComplexEventProcessing.Linq Namespace