Package dev.frostlake.functions.aggregate

Class MedianAccumulator

java.lang.Object

dev.frostlake.functions.aggregate.MedianAccumulator

All Implemented Interfaces:

ApproximateAwareAccumulator, CoercedNumericArgumentAccumulator, AggregateFunction.Accumulator

public class MedianAccumulator
extends Object
implements AggregateFunction.Accumulator, ApproximateAwareAccumulator, CoercedNumericArgumentAccumulator

Accumulator for Median, delegating to AggregateNumerics.median(Iterable) so the interpolating percentiles share one typing rule. The values are kept AS THEY ARRIVE rather than as doubles: the median's scale is the input's plus three, and a value collapsed to a double has no scale left to derive it from. A VARCHAR or VARIANT argument is told apart by DECLARATION (CoercedNumericArgumentAccumulator) and takes live's whole-number rule instead.

Constructor Summary

Constructors

Constructor	Description
MedianAccumulator()

Method Summary

Modifier and Type	Method	Description
void	accumulate(Object v)	Folds one row's argument value into the running state.
Object	getResult()	The aggregate's result over everything accumulated so far.
void	merge(AggregateFunction.Accumulator other)	Folds another accumulator's state into this one, combining two partial aggregations of the same group.
void	reset()	Clears the state back to the empty-group starting point so the accumulator can be reused.
void	setApproximateArgument(boolean approximate)	Tell the accumulator what its argument's declared type is.
void	setCoercedNumericArgument(boolean coerced)	Tell the accumulator whether its argument is declared VARCHAR or VARIANT.

Methods inherited from class java.lang.Object

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

Constructor Details

MedianAccumulator

public MedianAccumulator()

Method Details

setApproximateArgument

public void setApproximateArgument(boolean approximate)

Description copied from interface: ApproximateAwareAccumulator

Tell the accumulator what its argument's declared type is.

Specified by:

setApproximateArgument in interface ApproximateAwareAccumulator

Parameters:

approximate - whether the aggregated expression is declared FLOAT / DOUBLE / REAL

setCoercedNumericArgument

public void setCoercedNumericArgument(boolean coerced)

Description copied from interface: CoercedNumericArgumentAccumulator

Tell the accumulator whether its argument is declared VARCHAR or VARIANT.

Specified by:

setCoercedNumericArgument in interface CoercedNumericArgumentAccumulator

Parameters:

coerced - whether the aggregated expression is text or VARIANT, converted value by value

accumulate

public void accumulate(Object v)

Description copied from interface: AggregateFunction.Accumulator

Folds one row's argument value into the running state.

Specified by:

accumulate in interface AggregateFunction.Accumulator

Parameters:

v - the aggregate argument's value for one row; SQL NULL arrives as null

getResult

public Object getResult()

Description copied from interface: AggregateFunction.Accumulator

The aggregate's result over everything accumulated so far.

Specified by:

getResult in interface AggregateFunction.Accumulator

Returns:

the group's result, or null where the aggregate defines an empty group as NULL

reset

public void reset()

Description copied from interface: AggregateFunction.Accumulator

Clears the state back to the empty-group starting point so the accumulator can be reused.

Specified by:

reset in interface AggregateFunction.Accumulator

merge

public void merge(AggregateFunction.Accumulator other)

Description copied from interface: AggregateFunction.Accumulator

Folds another accumulator's state into this one, combining two partial aggregations of the same group.

Specified by:

merge in interface AggregateFunction.Accumulator

Parameters:

other - a partial state of the same aggregate implementation