The Table Expression Selection id used with aggregation. More...

#include <TableExprIdAggr.h>

Inheritance diagram for casacore::TableExprIdAggr:

Public Member Functions
	TableExprIdAggr (const CountedPtr< TableExprGroupResult > &result)
	Construct it from the aggregation results. More...

const TableExprGroupResult &	result () const
	Get out the aggregation result object. More...

uInt	getMagicValue () const
	Get the magic value (to check if correct). More...

Public Member Functions inherited from casacore::TableExprId
	TableExprId ()
	Default constructor sets rownr to -1. More...

	TableExprId (rownr_t rowNumber)
	Construct it from a row number. More...

	TableExprId (const RecordInterface &)
	Construct it from a Record object. More...

	TableExprId (const TableExprData &data)
	Construct it from pointers to data. More...

	~TableExprId ()

Bool	byRow () const
	Is the id given by row number? More...

Bool	byRecord () const
	Is the id given as a RecordInterface? More...

Bool	byData () const
	Is the id given as a TableExprData? More...

Int64	rownr () const
	Get the row number. More...

const RecordInterface &	record () const
	Get the Record reference. More...

const TableExprData &	data () const
	Get the data reference. More...

void	setRownr (rownr_t rownr)
	Set the row number. More...

void	setRecord (const RecordInterface &)
	Set the record. More...

Static Public Member Functions
static const TableExprIdAggr &	cast (const TableExprId &id)
	Cast a TableExprId object to TableExprIdAggr. More...

Private Attributes
uInt	itsMagicValue

CountedPtr< TableExprGroupResult >	itsResult

Detailed Description

The Table Expression Selection id used with aggregation.

Intended use:

Public interface

Review Status

Reviewed By:: UNKNOWN
Date Reviewed:: before2004/08/25
Test programs:: tExprGroup

Synopsis

This class provides the user the ability to identify the data objects to test in a TaQL expression using aggregate functions.
It adds a TableExprGroupResult object to the TableExprId class which is used by the various classes derived from TableExprGroupFuncBase to get or evaluate the aggregated value. An aggregated value can be determined in two ways:

An immediate aggregate function has calculated its value in its apply function. Each group has a TableExprGroupFuncSet containing the values of all immediate aggregate functions of that group. A vector of these objects is part of of TableExprGroupResult and is used by the TableExprAggrNode(Array) get functions to return the correct value.
A lazy aggregate function calculates the value as part of its get function. It uses the vector of TableExprId objects in TableExprGroupResult to know which rows (or records) belong to which group. Note that UDF aggregate functions are always lazy.

TableExprIdAggr contains a static function to (statically) cast a TableExprId object to TableExprIdAggr. A magic value is used to check that the cast is valid.
No dynamic_cast is used, because it requires TableExprId to contain virtual functions making the object larger. TaQL can hold quite large vectors of TableExprId objects, so such overhead is unacceptably large.

Motivation

This class makes it possible to retrieve aggregated values using the standard get functions taking an TableExprId.

Definition at line 86 of file TableExprIdAggr.h.

Constructor & Destructor Documentation

casacore::TableExprIdAggr::TableExprIdAggr ( const CountedPtr< TableExprGroupResult > & result )

inlineexplicit

Construct it from the aggregation results.

Definition at line 90 of file TableExprIdAggr.h.

Member Function Documentation

static const TableExprIdAggr& casacore::TableExprIdAggr::cast ( const TableExprId & id )

inlinestatic

Cast a TableExprId object to TableExprIdAggr.

It checks if the cast is correct by checking the magic value.

Definition at line 105 of file TableExprIdAggr.h.

References AlwaysAssert, and getMagicValue().

uInt casacore::TableExprIdAggr::getMagicValue ( ) const

inline

Get the magic value (to check if correct).

Definition at line 100 of file TableExprIdAggr.h.

References itsMagicValue.

Referenced by cast().

const TableExprGroupResult& casacore::TableExprIdAggr::result ( ) const

inline

Get out the aggregation result object.

Definition at line 96 of file TableExprIdAggr.h.

References itsResult.

Member Data Documentation

uInt casacore::TableExprIdAggr::itsMagicValue

private

Definition at line 113 of file TableExprIdAggr.h.

Referenced by getMagicValue().

CountedPtr<TableExprGroupResult> casacore::TableExprIdAggr::itsResult

private

Definition at line 114 of file TableExprIdAggr.h.

Referenced by result().

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

tables/TaQL/TableExprIdAggr.h

Public Member Functions

Static Public Member Functions

Private Attributes