org.apache.druid.query.topn.types

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

java.lang.Object

org.apache.druid.query.topn.types.NumericTopNColumnSelectorStrategy<ValueSelectorType,DimExtractionAggregateStoreType>

All Implemented Interfaces:

ColumnSelectorStrategy, TopNColumnSelectorStrategy<ValueSelectorType,DimExtractionAggregateStoreType>

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

Field Summary

Fields inherited from interface org.apache.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, StorageAdapter storageAdapter) Used by DimExtractionTopNAlgorithm.
static TopNColumnSelectorStrategy	ofType(ValueType selectorType, ValueType dimensionType)
void	updateDimExtractionResults(DimExtractionAggregateStoreType aggregatesStore, 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 org.apache.druid.query.topn.types.TopNColumnSelectorStrategy

dimExtractionScanAndAggregate, makeDimExtractionAggregateStore

Constructor Detail

NumericTopNColumnSelectorStrategy

public NumericTopNColumnSelectorStrategy()

Method Detail

ofType

public static TopNColumnSelectorStrategy ofType(ValueType selectorType,
                                                ValueType dimensionType)

getCardinality

public int getCardinality(ValueSelectorType selector)

Specified by:

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

getDimExtractionRowSelector

public Aggregator[][] getDimExtractionRowSelector(TopNQuery query,
                                                  TopNParams params,
                                                  StorageAdapter storageAdapter)

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,DimExtractionAggregateStoreType extends Map<?,Aggregator[]>>

Parameters:

query - The TopN query being served

params - Parameters for the TopN query being served

storageAdapter - Column storage adapter, to provide information about the column that can be used for query optimization, e.g. whether dimension values are sorted or not

Returns:

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

updateDimExtractionResults

public void updateDimExtractionResults(DimExtractionAggregateStoreType aggregatesStore,
                                       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,DimExtractionAggregateStoreType extends Map<?,Aggregator[]>>

Parameters:

aggregatesStore - Map created by makeDimExtractionAggregateStore()

resultBuilder - TopN result builder