org.apache.druid.query.aggregation

Class NullableAggregateCombiner<T>

java.lang.Object

org.apache.druid.query.aggregation.NullableAggregateCombiner<T>

All Implemented Interfaces:

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

public final class NullableAggregateCombiner<T>
extends Object
implements AggregateCombiner<T>

The result of a NullableAggregateCombiner will be null if all the values to be combined are null values or no values are combined at all. If any of the value is non-null, the result would be the value of the delegate combiner. Note that the delegate combiner is not required to perform check for BaseNullableColumnValueSelector.isNull() on the selector as only non-null values will be passed to the delegate combiner. This class is only used when SQL compatible null handling is enabled.

Field Summary

Fields inherited from interface org.apache.druid.segment.ColumnValueSelector

EMPTY_ARRAY

Constructor Summary

Constructors

Constructor and Description
NullableAggregateCombiner(AggregateCombiner<T> delegate)

Method Summary

Modifier and Type	Method and Description
Class	classOfObject()
void	fold(ColumnValueSelector selector) Folds this AggregateCombiner's state value with the value of the given selector and saves it in this AggregateCombiner's state, e.
double	getDouble()
float	getFloat()
long	getLong()
T	getObject()
boolean	isNull() Returns true if selected primitive value is null for BaseFloatColumnValueSelector, BaseLongColumnValueSelector and BaseDoubleColumnValueSelector otherwise false.
void	reset(ColumnValueSelector selector) Resets this AggregateCombiner's state value to the value of the given selector, e.

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.aggregation.AggregateCombiner

inspectRuntimeShape

Constructor Detail

NullableAggregateCombiner

public NullableAggregateCombiner(AggregateCombiner<T> delegate)

Method Detail

reset

public void reset(ColumnValueSelector selector)

Description copied from interface: AggregateCombiner

Resets this AggregateCombiner's state value to the value of the given selector, e. g. after calling this method combiner.get*() should return the same value as selector.get*(). If the selector is an ObjectColumnSelector, the object returned from BaseObjectColumnValueSelector.getObject() must not be modified, and must not become a subject for modification during subsequent AggregateCombiner.fold(org.apache.druid.segment.ColumnValueSelector) calls.

Specified by:

reset in interface AggregateCombiner<T>

fold

public void fold(ColumnValueSelector selector)

Description copied from interface: AggregateCombiner

Folds this AggregateCombiner's state value with the value of the given selector and saves it in this AggregateCombiner's state, e. g. after calling combiner.fold(selector), combiner.get*() should return the value that would be the result of aggregatorFactory.combine(combiner.get*(), selector.get*()) call. Unlike AggregatorFactory.combine(java.lang.Object, java.lang.Object), if the selector is an ObjectColumnSelector, the object returned from BaseObjectColumnValueSelector.getObject() must not be modified, and must not become a subject for modification during subsequent fold() calls. Since the state of AggregateCombiner is undefined before AggregateCombiner.reset(org.apache.druid.segment.ColumnValueSelector) is ever called on it, the effects of calling fold() are also undefined in this case.

Specified by:

fold in interface AggregateCombiner<T>

See Also:

AggregatorFactory.combine(java.lang.Object, java.lang.Object)

getFloat

public float getFloat()

Specified by:

getFloat in interface BaseFloatColumnValueSelector

getDouble

public double getDouble()

Specified by:

getDouble in interface BaseDoubleColumnValueSelector

getLong

public long getLong()

Specified by:

getLong in interface BaseLongColumnValueSelector

isNull

public boolean isNull()

Description copied from interface: BaseNullableColumnValueSelector

Returns true if selected primitive value is null for BaseFloatColumnValueSelector, BaseLongColumnValueSelector and BaseDoubleColumnValueSelector otherwise false.

Specified by:

isNull in interface AggregateCombiner<T>

Specified by:

isNull in interface BaseNullableColumnValueSelector

getObject

@Nullable
public T getObject()

Specified by:

getObject in interface BaseObjectColumnValueSelector<T>

classOfObject

public Class classOfObject()

Specified by:

classOfObject in interface BaseObjectColumnValueSelector<T>