casacore::TableMeasColumn Class Reference

Read only access to table scalar Measure columns. More...

#include <TableMeasColumn.h>

Inheritance diagram for casacore::TableMeasColumn:

Public Member Functions
	TableMeasColumn ()
	The default constructor creates a null object.
	TableMeasColumn (const Table &tab, const String &columnName)
	Create the ScalarMeasColumn from the table and column Name.
	TableMeasColumn (const TableMeasColumn &that)
	Copy constructor (copy semantics).
virtual	~TableMeasColumn ()
void	reference (const TableMeasColumn &that)
	Change the reference to another column.
void	attach (const Table &tab, const String &columnName)
	Attach another column to the object.
Bool	isDefined (uInt rownr) const
	Tests if a row contains a Measure (i.e., if the row has a defined value).
const TableMeasDescBase &	measDesc () const
	Get access to the TableMeasDescBase describing the column.
TableMeasDescBase &	measDesc ()
Bool	isNull () const
	Test if the object is null.
void	throwIfNull () const
	Throw an exception if the object is null.
const String &	columnName () const
	Get the name of the column.
Table	table () const
	Get the Table object this column belongs to.
Bool	isScalar () const
	Is the column a scalar measures column? It is if the underlying column is a scalar column or an array column with a fixed 1-dimensional shape.
Protected Attributes
uInt	itsNvals
CountedPtr< TableMeasDescBase >	itsDescPtr
TableColumn	itsTabDataCol
Bool	itsVarRefFlag
Bool	itsVarOffFlag
Private Member Functions
TableMeasColumn &	operator= (const TableMeasColumn &that)
	Assignment makes no sense in a readonly class.

Detailed Description

Read only access to table scalar Measure columns.

Intended use:

Public interface

Review Status

Reviewed By:: Bob Garwood
Date Reviewed:: 1999/12/23
Test programs:: tTableMeasures

Prerequisite

Measures
Tables
TableMeasDesc

Synopsis

TableMeasColumn is the base class for the templated classes ScalarMeasColumn and ArrayMeasColumn which give access to table columns containing measures .

This base class offers some common functionality like getting the column name and testing if a row of the column contains a value. Its main function is measDesc(), which gives access to the TableMeasDescBase object containing a description of the measure column.

Example

 // Create the object for measure column Time1.
 TableMeasColumn timeCol(tab, "Time1");
 
 // print some details about the column
 if (timeCol.measDesc().isRefCodeVariable()) {
 cout << "The column has variable references." << endl;
 } else {
 cout << "The fixed MeasRef for the column is: "
 << timeCol.getMeasRef() << endl;
 }

Motivation

This class contains the common functionality for the templated derived classes.

Definition at line 98 of file TableMeasColumn.h.

Constructor & Destructor Documentation

casacore::TableMeasColumn::TableMeasColumn ( )

The default constructor creates a null object.

Useful for creating arrays of ScalarMeasColumn objects. Attempting to use a null object will produce a segmentation fault so care needs to be taken to initialise the objects first by using attach(). An ScalarMeasColumn object can be tested if it is null by using the isNull() member.

casacore::TableMeasColumn::TableMeasColumn	(	const Table &	tab,
		const String &	columnName
	)

Create the ScalarMeasColumn from the table and column Name.

casacore::TableMeasColumn::TableMeasColumn ( const TableMeasColumn & that )

Copy constructor (copy semantics).

virtual casacore::TableMeasColumn::~TableMeasColumn ( ) [virtual]

Member Function Documentation

void casacore::TableMeasColumn::attach	(	const Table &	tab,
		const String &	columnName
	)

Attach another column to the object.

const String& casacore::TableMeasColumn::columnName ( ) const

Get the name of the column.

Bool casacore::TableMeasColumn::isDefined ( uInt rownr ) const

Tests if a row contains a Measure (i.e., if the row has a defined value).

Bool casacore::TableMeasColumn::isNull ( ) const [inline]

Test if the object is null.

Definition at line 136 of file TableMeasColumn.h.

References itsDescPtr, and casacore::CountedPtr< t >::null().

Bool casacore::TableMeasColumn::isScalar ( ) const

Is the column a scalar measures column? It is if the underlying column is a scalar column or an array column with a fixed 1-dimensional shape.

Otherwise it is an array measures column.
Caution: It is not 100% determined if a measure column is an array or a scalar; If the underlying table column is an array with a variable shape, this function will see it as an array measure column; However, it might be accessible as a scalar measure column;

TableMeasDescBase& casacore::TableMeasColumn::measDesc ( ) [inline]

Definition at line 131 of file TableMeasColumn.h.

References itsDescPtr.

const TableMeasDescBase& casacore::TableMeasColumn::measDesc ( ) const [inline]

Get access to the TableMeasDescBase describing the column.

Definition at line 129 of file TableMeasColumn.h.

References itsDescPtr.

TableMeasColumn& casacore::TableMeasColumn::operator= ( const TableMeasColumn & that ) [private]