Package org.apache.druid.query.aggregation

Class AggregatorAdapters

java.lang.Object

org.apache.druid.query.aggregation.AggregatorAdapters

public class AggregatorAdapters
extends Object

A class that helps query engines use Buffer- or VectorAggregators in a consistent way. The two main benefits this class provides are: (1) Query engines can treat BufferAggregators and VectorAggregators the same for operations that are equivalent across them, like "init", "get", "relocate", and "close". (2) Query engines are freed from the need to manage how much space each individual aggregator needs. They only need to allocate a block of size "spaceNeeded".

Method Summary

Modifier and Type	Method	Description
void	aggregateBuffered(ByteBuffer buf, int position)	Call BufferAggregator.aggregate(ByteBuffer, int) on all of our aggregators.
void	aggregateVector(ByteBuffer buf, int numRows, int[] positions, int[] rows)	Call VectorAggregator.aggregate(ByteBuffer, int, int[], int[], int) on all of our aggregators.
void	aggregateVector(ByteBuffer buf, int position, int start, int end)	Call VectorAggregator.aggregate(ByteBuffer, int, int, int) on all of our aggregators.
int[]	aggregatorPositions()	Return the individual positions of each aggregator within a hypothetical buffer of size spaceNeeded().
List<AggregatorFactory>	factories()	Return the AggregatorFactory objects that were used to create this object.
static AggregatorAdapters	factorizeBuffered(ColumnSelectorFactory columnSelectorFactory, List<AggregatorFactory> aggregatorFactories)	Create an adapters object based on BufferAggregator.
static AggregatorAdapters	factorizeVector(VectorColumnSelectorFactory columnSelectorFactory, List<AggregatorFactory> aggregatorFactories)	Create an adapters object based on VectorAggregator.
Object	get(ByteBuffer buf, int position, int aggregatorNumber)	Retrieve aggregation state from one of our aggregators.
void	init(ByteBuffer buf, int position)	Initialize all aggregators.
void	relocate(int oldPosition, int newPosition, ByteBuffer oldBuffer, ByteBuffer newBuffer)	Inform all of our aggregators that they are being relocated.
void	reset()	Reset all of our aggregators, releasing resources held by them.
int	size()	Return the number of aggregators in this object.
int	spaceNeeded()	Return the amount of buffer bytes needed by all aggregators wrapped up in this object.

Methods inherited from class java.lang.Object

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

Method Detail

factorizeVector

public static AggregatorAdapters factorizeVector(VectorColumnSelectorFactory columnSelectorFactory,
                                                 List<AggregatorFactory> aggregatorFactories)

Create an adapters object based on VectorAggregator.

factorizeBuffered

public static AggregatorAdapters factorizeBuffered(ColumnSelectorFactory columnSelectorFactory,
                                                   List<AggregatorFactory> aggregatorFactories)

Create an adapters object based on BufferAggregator.

spaceNeeded

public int spaceNeeded()

Return the amount of buffer bytes needed by all aggregators wrapped up in this object.

factories

public List<AggregatorFactory> factories()

Return the AggregatorFactory objects that were used to create this object.

aggregatorPositions

public int[] aggregatorPositions()

Return the individual positions of each aggregator within a hypothetical buffer of size spaceNeeded().

size

public int size()

Return the number of aggregators in this object.

init

public void init(ByteBuffer buf,
                 int position)

Initialize all aggregators.

Parameters:

buf - aggregation buffer

position - position in buffer where our block of size spaceNeeded() starts

aggregateBuffered

public void aggregateBuffered(ByteBuffer buf,
                              int position)

Call BufferAggregator.aggregate(ByteBuffer, int) on all of our aggregators. This method is only valid if the underlying aggregators are BufferAggregator.

aggregateVector

public void aggregateVector(ByteBuffer buf,
                            int position,
                            int start,
                            int end)

Call VectorAggregator.aggregate(ByteBuffer, int, int, int) on all of our aggregators. This method is only valid if the underlying aggregators are VectorAggregator.

aggregateVector

public void aggregateVector(ByteBuffer buf,
                            int numRows,
                            int[] positions,
                            @Nullable
                            int[] rows)

Call VectorAggregator.aggregate(ByteBuffer, int, int[], int[], int) on all of our aggregators. This method is only valid if the underlying aggregators are VectorAggregator.

get

@Nullable
public Object get(ByteBuffer buf,
                  int position,
                  int aggregatorNumber)

Retrieve aggregation state from one of our aggregators.

Parameters:

buf - aggregation buffer

position - position in buffer where our block of size spaceNeeded() starts

aggregatorNumber - which aggregator to retrieve state, from 0 to size() - 1

relocate

public void relocate(int oldPosition,
                     int newPosition,
                     ByteBuffer oldBuffer,
                     ByteBuffer newBuffer)

Inform all of our aggregators that they are being relocated.

reset

public void reset()

Reset all of our aggregators, releasing resources held by them. After this, this instance may be reused or it may be discarded.