io.druid.query.topn.types

Class NumericTopNColumnSelectorStrategy<ValueSelectorType extends ColumnValueSelector,DimExtractionAggregateStoreType extends Map<?,Aggregator[]>>

java.lang.Object

io.druid.query.topn.types.NumericTopNColumnSelectorStrategy<ValueSelectorType,DimExtractionAggregateStoreType>

All Implemented Interfaces:

ColumnSelectorStrategy, TopNColumnSelectorStrategy<ValueSelectorType,DimExtractionAggregateStoreType>

public abstract class NumericTopNColumnSelectorStrategy<ValueSelectorType extends ColumnValueSelector,DimExtractionAggregateStoreType extends Map<?,Aggregator[]>>
extends Object
implements TopNColumnSelectorStrategy<ValueSelectorType,DimExtractionAggregateStoreType>

Field Summary

Fields inherited from interface io.druid.query.topn.types.TopNColumnSelectorStrategy

CARDINALITY_UNKNOWN

Constructor Summary

Constructors

Constructor and Description
NumericTopNColumnSelectorStrategy()

Method Summary

Modifier and Type	Method and Description
int	getCardinality(ValueSelectorType selector)
Aggregator[][]	getDimExtractionRowSelector(TopNQuery query, TopNParams params, Capabilities capabilities) Used by DimExtractionTopNAlgorithm.
void	updateDimExtractionResults(DimExtractionAggregateStoreType aggregatesStore, com.google.common.base.Function<Object,Object> valueTransformer, TopNResultBuilder resultBuilder) Used by DimExtractionTopNAlgorithm.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.druid.query.topn.types.TopNColumnSelectorStrategy

dimExtractionScanAndAggregate, getValueType, makeDimExtractionAggregateStore

Constructor Detail

NumericTopNColumnSelectorStrategy

public NumericTopNColumnSelectorStrategy()

Method Detail

getCardinality

public int getCardinality(ValueSelectorType selector)

Specified by:

getCardinality in interface TopNColumnSelectorStrategy<ValueSelectorType extends ColumnValueSelector,DimExtractionAggregateStoreType extends Map<?,Aggregator[]>>

getDimExtractionRowSelector

public Aggregator[][] getDimExtractionRowSelector(TopNQuery query,
                                                  TopNParams params,
                                                  Capabilities capabilities)

Description copied from interface: TopNColumnSelectorStrategy

Used by DimExtractionTopNAlgorithm. Create an Aggregator[][] using BaseTopNAlgorithm.AggregatorArrayProvider and the given parameters. As the Aggregator[][] is used as an integer-based lookup, this method is only applicable for dimension types that use integer row values. A dimension type that does not have integer values should return null.

Specified by:

getDimExtractionRowSelector in interface TopNColumnSelectorStrategy<ValueSelectorType extends ColumnValueSelector,DimExtractionAggregateStoreType extends Map<?,Aggregator[]>>

Parameters:

query - The TopN query being served

params - Parameters for the TopN query being served

capabilities - Object indicating if dimension values are sorted

Returns:

an Aggregator[][] for integer-valued dimensions, null otherwise

updateDimExtractionResults

public void updateDimExtractionResults(DimExtractionAggregateStoreType aggregatesStore,
                                       com.google.common.base.Function<Object,Object> valueTransformer,
                                       TopNResultBuilder resultBuilder)

Description copied from interface: TopNColumnSelectorStrategy

Used by DimExtractionTopNAlgorithm. Read entries from the aggregates store, adding the keys and associated values to the resultBuilder, applying the valueTransformer to the keys if present

Specified by:

updateDimExtractionResults in interface TopNColumnSelectorStrategy<ValueSelectorType extends ColumnValueSelector,DimExtractionAggregateStoreType extends Map<?,Aggregator[]>>

Parameters:

aggregatesStore - Map created by makeDimExtractionAggregateStore()

valueTransformer - Converts keys to different types, if null no conversion is needed

resultBuilder - TopN result builder