io.druid.query.aggregation

Interface Aggregator

All Known Implementing Classes:

ApproximateHistogramAggregator, ApproximateHistogramFoldingAggregator, CardinalityAggregator, CountAggregator, DoubleMaxAggregator, DoubleMinAggregator, DoubleSumAggregator, FilteredAggregator, HistogramAggregator, HyperUniquesAggregator, JavaScriptAggregator, LongMaxAggregator, LongMinAggregator, LongSumAggregator

public interface Aggregator

An Aggregator is an object that can aggregate metrics. Its aggregation-related methods (namely, aggregate() and get()) do not take any arguments as the assumption is that the Aggregator was given something in its constructor that it can use to get at the next bit of data. Thus, an Aggregator can be thought of as a closure over some other thing that is stateful and changes between calls to aggregate(). This is currently (as of this documentation) implemented through the use of Offset and FloatColumnSelector objects. The Aggregator has a handle on a FloatColumnSelector object which has a handle on an Offset. QueryableIndex has both the Aggregators and the Offset object and iterates through the Offset calling the aggregate() method on the Aggregators for each applicable row. This interface is old and going away. It is being replaced by BufferAggregator

Method Summary

Methods

Modifier and Type	Method and Description
void	aggregate()
void	close()
Object	get()
float	getFloat()
long	getLong()
String	getName()
void	reset()

Method Detail

aggregate

void aggregate()

reset

void reset()

get

Object get()

getFloat

float getFloat()

getName

String getName()

close

void close()

getLong

long getLong()