Package com.illumon.iris.db.v2.by

Interface AggregationStateFactory

All Known Implementing Classes:

AbsSumStateFactory, AggregationFormulaStateFactory, AggregationIndexStateFactory, AppendMinMaxByStateFactoryImpl, AvgStateFactory, ComboAggregateFactory, CountByStateFactoryImpl, CountDistinctStateFactory, DistinctStateFactory, FirstByStateFactoryImpl, IterativeIndexStateFactory, IterativeOperatorStateFactory, KeyOnlyFirstOrLastByStateFactory, LastByStateFactoryImpl, MinMaxByStateFactoryImpl, PercentileByStateFactoryImpl, ReaggregatableStatefactory, SelectDistinctStateFactoryImpl, SortedFirstBy, SortedFirstOrLastByFactoryImpl, SortedLastBy, StdStateFactory, SumStateFactory, TrackingFirstByStateFactoryImpl, TrackingLastByStateFactoryImpl, UniqueStateFactory, VarStateFactory, WeightedAverageStateFactoryImpl, WeightedSumStateFactoryImpl

public interface AggregationStateFactory

The aggregation state factory is passed to the by operation, and is used to create new aggregation states for each of the output rows (or in case of byExternal, each of the output tables). The factory also returns the result column sources.

Method Summary

Modifier and Type	Method	Description
default AggregationMemoKey	getMemoKey()	Produces a MemoKey for this aggregation state factory.

Method Details

getMemoKey

default AggregationMemoKey getMemoKey()

Produces a MemoKey for this aggregation state factory.

If two AggregationStateFactories have equal memoKeys, then Table.by(com.illumon.iris.db.v2.by.AggregationStateFactory, com.illumon.iris.db.v2.select.SelectColumn...) operations that have the same group by columns may be memoized. In that case instead of recomputing the result; the original result will be used.

If null is returned, the operation will not be memoized.

Returns:

an AggregationMemoKey, null if this operation can not be memoized.