net.esper.eql.expression
Interface AggregationService

All Superinterfaces:
AggregationResultFuture
All Known Implementing Classes:
AggregationServiceBase, AggregationServiceGroupAllImpl, AggregationServiceGroupByImpl, AggregationServiceNull

public interface AggregationService
extends AggregationResultFuture

Service for maintaing aggregation state. Processes events entering (a window, a join etc,) and events leaving. Answers questions about current aggrataion state for a given row.


Method Summary
 void applyEnter(EventBean[] eventsPerStream, MultiKey optionalGroupKeyPerRow)
          Apply events as entering a window (new events).
 void applyLeave(EventBean[] eventsPerStream, MultiKey optionalGroupKeyPerRow)
          Apply events as leaving a window (old events).
 void setCurrentRow(MultiKey groupKey)
          Set the current aggregation state row - for use when evaluation nodes are asked to evaluate.
 
Methods inherited from interface net.esper.eql.expression.AggregationResultFuture
getValue
 

Method Detail

applyEnter

void applyEnter(EventBean[] eventsPerStream,
                MultiKey optionalGroupKeyPerRow)
Apply events as entering a window (new events).

Parameters:
eventsPerStream - - events for each stream entering window
optionalGroupKeyPerRow - - can be null if grouping without keys is desired, else the keys to use for grouping, each distinct key value results in a new row of aggregation state.

applyLeave

void applyLeave(EventBean[] eventsPerStream,
                MultiKey optionalGroupKeyPerRow)
Apply events as leaving a window (old events).

Parameters:
eventsPerStream - - events for each stream entering window
optionalGroupKeyPerRow - - can be null if grouping without keys is desired, else the keys to use for grouping, each distinct key value results in a new row of aggregation state.

setCurrentRow

void setCurrentRow(MultiKey groupKey)
Set the current aggregation state row - for use when evaluation nodes are asked to evaluate.

Parameters:
groupKey - - key identify the row of aggregation states