org.apache.druid.segment

Interface ColumnValueSelector<T>

All Superinterfaces:

BaseDoubleColumnValueSelector, BaseFloatColumnValueSelector, BaseLongColumnValueSelector, BaseNullableColumnValueSelector, BaseObjectColumnValueSelector<T>, HotLoopCallee

All Known Subinterfaces:

AggregateCombiner<T>, DimensionSelector, DoubleColumnSelector, FloatColumnSelector, HistoricalColumnSelector<T>, HistoricalDimensionSelector, LongColumnSelector, SettableColumnValueSelector<T>, SingleValueHistoricalDimensionSelector

All Known Implementing Classes:

AbstractDimensionSelector, BaseSingleValueDimensionSelector, ConstantDimensionSelector, ConstantExprEvalSelector, DoubleAggregateCombiner, DoubleWrappingDimensionSelector, ExpressionColumnValueSelector, FloatWrappingDimensionSelector, HyperLogLogCollectorAggregateCombiner, IncrementalIndexRowHolder, IndexedTableColumnValueSelector, IndexedTableDimensionSelector, LongAggregateCombiner, LongSumAggregateCombiner, LongWrappingDimensionSelector, MultiValueExpressionDimensionSelector, NilColumnValueSelector, NullableNumericAggregateCombiner, ObjectAggregateCombiner, ObjectColumnSelector, PossiblyNullColumnValueSelector, PossiblyNullDimensionSelector, RowBasedExpressionColumnValueSelector, SettableDimensionValueSelector, SettableDoubleColumnValueSelector, SettableFloatColumnValueSelector, SettableLongColumnValueSelector, SettableObjectColumnValueSelector, SingleLongInputCachingExpressionColumnValueSelector, SingleScanTimeDimensionSelector, SingleStringInputCachingExpressionColumnValueSelector, SingleStringInputDimensionSelector, StringFirstAggregateCombiner, StringLastAggregateCombiner

public interface ColumnValueSelector<T>
extends BaseLongColumnValueSelector, BaseDoubleColumnValueSelector, BaseFloatColumnValueSelector, BaseObjectColumnValueSelector<T>

Base type for interfaces that manage column value selection, e.g. DimensionSelector, LongColumnSelector. This interface has methods to get the value in all primitive types, that have corresponding basic aggregators in Druid: Sum, Min, Max, etc: BaseFloatColumnValueSelector.getFloat(), BaseDoubleColumnValueSelector.getDouble() and BaseLongColumnValueSelector.getLong() to support "polymorphic" rollup aggregation during index merging. "Absent" column, i. e. that always returns zero from BaseLongColumnValueSelector.getLong(), BaseFloatColumnValueSelector.getFloat() and BaseDoubleColumnValueSelector.getDouble() methods and null from BaseObjectColumnValueSelector.getObject(), should always be an instance of NilColumnValueSelector. `selector instanceof NilColumnValueSelector` is the recommended way to check for this condition.

Field Summary

Fields

Modifier and Type	Field and Description
static ColumnValueSelector[]	EMPTY_ARRAY

Method Summary

Methods inherited from interface org.apache.druid.segment.BaseLongColumnValueSelector

getLong

Methods inherited from interface org.apache.druid.segment.BaseDoubleColumnValueSelector

getDouble

Methods inherited from interface org.apache.druid.segment.BaseFloatColumnValueSelector

getFloat

Methods inherited from interface org.apache.druid.query.monomorphicprocessing.HotLoopCallee

inspectRuntimeShape

Methods inherited from interface org.apache.druid.segment.BaseNullableColumnValueSelector

isNull

Methods inherited from interface org.apache.druid.segment.BaseObjectColumnValueSelector

classOfObject, getObject

Field Detail

EMPTY_ARRAY

static final ColumnValueSelector[] EMPTY_ARRAY