Aggregator Struct Reference

Abstract interface for an incremental aggregate accumulator. More...

#include "Aggregation.h"

Inheritance diagram for Aggregator:

Public Member Functions
virtual	~Aggregator ()=default
virtual void	add (const AggValue &x)=0
	Incorporate one input value into the running aggregate.
virtual AggValue	finalize () const =0
	Return the final aggregate result.
virtual ValueType	inputType () const =0
	Return the type of the input values accepted by add().
virtual ValueType	resultType () const
	Return the type of the value returned by finalize().

Detailed Description

Abstract interface for an incremental aggregate accumulator.

Each concrete subclass implements one aggregation function for one input type (e.g., SUM over integers, MAX over floats). Instances are created by makeAggregator().

Definition at line 139 of file Aggregation.h.

Constructor & Destructor Documentation

~Aggregator()

virtual Aggregator::~Aggregator ( )

virtualdefault

Member Function Documentation

add()

virtual void Aggregator::add ( const AggValue & x )

pure virtual

Incorporate one input value into the running aggregate.

Parameters

x	Input value to add.

Implemented in AvgAgg< T >, ChooseAgg< T >, MaxAgg< T >, MinAgg< T >, and SumAgg< T >.

finalize()

virtual AggValue Aggregator::finalize ( ) const

pure virtual

Return the final aggregate result.

Returns

The accumulated aggregate as an AggValue.

Implemented in AvgAgg< T >, and StandardAgg< T >.

inputType()

virtual ValueType Aggregator::inputType ( ) const

pure virtual

Return the type of the input values accepted by add().

Returns

The ValueType of values passed to add().

Used (via the resultType() default) to report the aggregate's result type; see makeAggregator() for the operators actually built.

Implemented in AvgAgg< T >, and StandardAgg< T >.

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resultType()

virtual ValueType Aggregator::resultType ( ) const

inlinevirtual

Return the type of the value returned by finalize().

Defaults to inputType(); override when the result type differs (e.g., AVG returns FLOAT regardless of the input type).

Returns

The ValueType of the value returned by finalize().

Reimplemented in AvgAgg< T >.

Definition at line 170 of file Aggregation.h.

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The documentation for this struct was generated from the following file:

• /home/senellar/git/software/provsql/src/Aggregation.h