Package dev.frostlake.functions.aggregate

Class SumAccumulator

java.lang.Object

dev.frostlake.functions.aggregate.SumAccumulator

All Implemented Interfaces:

ApproximateAwareAccumulator, AggregateFunction.Accumulator

public class SumAccumulator
extends Object
implements AggregateFunction.Accumulator, ApproximateAwareAccumulator

Accumulator for Sum.

Exact inputs sum exactly. A FLOAT input — by its runtime class, or by the argument's DECLARED type when its values arrive in an exact carrier — puts the whole sum on the double path, compensated the way the account adds doubles; a VARIANT input does the same (live: SUM of PARSE_JSON('1') and PARSE_JSON('2') is 3.0, SYSTEM$TYPEOF FLOAT). Every input feeds the double sum in order regardless, so the answer is the same whichever input first decides the tier.

Constructor Summary

Constructors

Constructor	Description
SumAccumulator()

Method Summary

Modifier and Type	Method	Description
void	accumulate(Object value)	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 declaredApproximate)	Tell the accumulator what its argument's declared type is.

Methods inherited from class java.lang.Object

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

Constructor Details

SumAccumulator

public SumAccumulator()

Method Details

setApproximateArgument

public void setApproximateArgument(boolean declaredApproximate)

Description copied from interface: ApproximateAwareAccumulator

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

Specified by:

setApproximateArgument in interface ApproximateAwareAccumulator

Parameters:

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

accumulate

public void accumulate(Object value)

Description copied from interface: AggregateFunction.Accumulator

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

Specified by:

accumulate in interface AggregateFunction.Accumulator

Parameters:

value - 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