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ScalarQuantColumn.h
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//# ScalarQuantColumn.h: Access to a Scalar Quantum Column in a table.
//# Copyright (C) 1997,1998,1999,2000,2001
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library is distributed in the hope that it will be useful, but WITHOUT
//# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//# Internet email: casa-feedback@nrao.edu.
//# Postal address: AIPS++ Project Office
//# National Radio Astronomy Observatory
//# 520 Edgemont Road
//# Charlottesville, VA 22903-2475 USA
#ifndef MEASURES_SCALARQUANTCOLUMN_H
#define MEASURES_SCALARQUANTCOLUMN_H
//# Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/Quanta/Quantum.h>
namespace casacore { //# NAMESPACE CASACORE - BEGIN
//# Forward Declarations
class Table;
template <class T> class ScalarColumn;
class String;
class Unit;
// <summary>
// Provides access to Scalar Quantum Columns in Tables.
// </summary>
// <use visibility=export>
// <reviewed reviewer="Bob Garwood" date="1999/12/23" tests="tTableQuantum.cc">
// </reviewed>
// <prerequisite>
//# Classes you should understand before using this one.
// <li> <linkto class=TableQuantumDesc>TableQuantumDesc</linkto>
// <li> <linkto class=Table>Table</linkto>
// <li> <linkto class=ScalarColumn>ScalarColumn</linkto>
// <li> <linkto class=Quantum>Quantum</linkto>
// </prerequisite>
// <synopsis>
// The ScalarQuantColumn class provides read/write access to quanta
// stored in a scalar Quantum Table column. The Quantum column should
// already exist in the table and would have been defined by means of a
// <linkto class=TableQuantumDesc>TableQuantumDesc object</linkto>.
// In addition,
// for a ScalarQuantColumn object to be useful the column should
// contain Quanta.
//
// A ScalarQuantColumn object is used much in the same way as a
// <linkto class=ScalarColumn>ScalarColumn</linkto> object.
//
// <h3>Quantum Units</h3></A>
// Quanta retrieved from the column will normally have the Unit that was
// specified when the Quantum column was defined.
// However, it is possible to override the default column Unit by
// supplying a Unit in the ScalarQuantColumn constructor.
// When constructed in this fashion the retrieved Quanta will by
// default be retrieved in this unit, i.e. they will by default be
// converted to this unit.
// <br>
// By giving a unit (as a Unit or Quantum object) to a get function,
// the data can be retrieved in another unit than the default.
// </synopsis>
// <example>
// <srcblock>
// Quantum<Double> q(5.3, "keV");
// // "QuantScalar" has previously been defined as a Quantum column
// // by means of a TableQuantumDesc. This example assumes the column
// // already contains quanta.
// ScalarQuantColumn<Double> qCol(qtab, "QuantScalar");
// // return and print quanta as stored in the column
// for (i = 0; i < qtab.nrow(); i++) {
// cout << qCol(i) << endl;
// }
// // The following retrieves and converts the quanta to GHz. They
// // are then divided by the Quantum constant QC::h (Planck).
// for (i=0; i < qtab.nrow(); i++) {
// cout << (qCol(i, "GHz"))/(QC::h);
// }
// </srcblock>
// </example>
// <motivation>
// Add support for Quanta in the Tables system.
// </motivation>
// <thrown>
// <li>TableInvOper if the Table column is null.
// </thrown>
// <todo asof="$DATE:$">
//# A List of bugs, limitations, extensions or planned refinements.
// <li> Functions like getColumn
// </todo>
template<class T> class ScalarQuantColumn
{
public:
// The default constructor creates a null object. It is useful for creating
// arrays of ScalarQuantColumn objects. Attempting to use a null object
// will produce a segmentation fault so care needs to be taken to
// initialise the objects by using the attach() member before any attempt
// is made to use the object. The isNull() member can be used to test
// if a ScalarQuantColumn object is null.
ScalarQuantColumn();
// Create the ScalarQuantColumn from the specified table and column name.
// The default unit for data retrieved is the unit in which they were stored.
ScalarQuantColumn (const Table& tab, const String& columnName);
// Create the ScalarQuantColumn from the specified table and column name.
// The default unit for data retrieved is the given unit (the data is
// converted as needed).
ScalarQuantColumn (const Table& tab, const String& columnName,
const Unit&);
// Copy constructor (copy semantics).
ScalarQuantColumn (const ScalarQuantColumn<T>& that);
~ScalarQuantColumn();
// Change the reference to another column.
void reference (const ScalarQuantColumn<T>& that);
// Attach a column to the object. Optionally supply a default unit
// which has the same meaning as the constructor unit argument.
// <group name="attach">
void attach (const Table& tab, const String& columnName);
void attach (const Table& tab, const String& columnName, const Unit&);
// </group>
// Get the quantum stored in the specified row.
// <group name="get">
void get (rownr_t rownr, Quantum<T>& q) const;
// Get the quantum in the specified row, converted to the given unit.
void get (rownr_t rownr, Quantum<T>& q, const Unit&) const;
// Get the quantum in the specified row, converted to the unit in other.
void get (rownr_t rownr, Quantum<T>& q, const Quantum<T>& other) const;
// </group>
// Return the quantum stored in the specified row.
// <group>
Quantum<T> operator() (rownr_t rownr) const;
// Return the quantum stored in the specified row, converted to the
// given unit.
Quantum<T> operator() (rownr_t rownr, const Unit&) const;
// Return the quantum in the specified row, converted to the unit in
// other.
Quantum<T> operator() (rownr_t rownr, const Quantum<T>& other) const;
// </group>
// Put a quantum into the table. If the column supports variable units
// the q's unit is stored into the unit column defined in the
// TableQuantumDesc object. If units are fixed for the column, the
// quantum is converted as needed.
void put (rownr_t rownr, const Quantum<T>& q);
// Test whether the Quantum column has variable units
Bool isUnitVariable() const
{ return (itsUnitsCol != 0); }
// Returns the column's value for Units as a string.
// An empty string is returned if the column has variable units.
const String& getUnits() const
{ return itsUnit.getName(); }
// Test if the object is null.
Bool isNull() const
{ return (itsDataCol == 0); }
// Throw an exception if the object is null.
void throwIfNull() const;
// Get the column as a Quantum<Vector<T> >. If <src>unit</src> is
// not empty, the returned Quantum will have that unit. Else if
// the units are variable, the values in the returned Vector
// have been converted to the unit of the 0th row entry. Otherwise,
// the units of the returned Quantum are the units specified in
// the column descriptor.
std::shared_ptr<Quantum<Vector<T> > > getColumn(const Unit& unit="") const;
protected:
//# Quantum column's units (if units not variable)
Unit itsUnit;
// Get access to itsUnitsCol.
const ScalarColumn<String>* unitsCol() const
{ return itsUnitsCol; }
private:
//# The underlying data column stores the quantum column's data.
ScalarColumn<T>* itsDataCol;
//# Variable units column if applicable.
ScalarColumn<String>* itsUnitsCol;
//# Unit to retrieve the data in.
Unit itsUnitOut;
//# Convert unit when getting data?
Bool itsConvOut;
// Assignment makes no sense in a read only class.
// Declaring this operator private makes it unusable.
ScalarQuantColumn& operator= (const ScalarQuantColumn<T>& that);
// Comparison is not defined, since its semantics are unclear.
Bool operator== (const ScalarQuantColumn<T>& that);
// Initialize the ScalarQuantColumn from the specified table and column.
void init (const Table& tab, const String& columnName);
// Deletes allocated memory etc. Called by destructor and any member
// which needs to reallocate data.
void cleanUp();
// Get the data without possible conversion.
void getData (rownr_t rownr, Quantum<T>& q) const;
};
} //# NAMESPACE CASACORE - END
//# Make old name ROScalarMeasColumn still available.
#define ROScalarQuantColumn ScalarQuantColumn
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/measures/TableMeasures/ScalarQuantColumn.tcc>
#endif //# CASACORE_NO_AUTO_TEMPLATES
#endif
casacore::Quantum
Definition Quantum.h:269
casacore::ScalarColumn
Definition ScalarColumn.h:83
casacore::ScalarQuantColumn::get
void get(rownr_t rownr, Quantum< T > &q) const
Get the quantum stored in the specified row.
casacore::ScalarQuantColumn::attach
void attach(const Table &tab, const String &columnName, const Unit &)
casacore::ScalarQuantColumn::getUnits
const String & getUnits() const
Returns the column's value for Units as a string.
Definition ScalarQuantColumn.h:185
casacore::ScalarQuantColumn::~ScalarQuantColumn
~ScalarQuantColumn()
casacore::ScalarQuantColumn::operator==
Bool operator==(const ScalarQuantColumn< T > &that)
Comparison is not defined, since its semantics are unclear.
casacore::ScalarQuantColumn::unitsCol
const ScalarColumn< String > * unitsCol() const
Get access to itsUnitsCol.
Definition ScalarQuantColumn.h:208
casacore::ScalarQuantColumn::isUnitVariable
Bool isUnitVariable() const
Test whether the Quantum column has variable units.
Definition ScalarQuantColumn.h:180
casacore::ScalarQuantColumn::operator()
Quantum< T > operator()(rownr_t rownr) const
Return the quantum stored in the specified row.
casacore::ScalarQuantColumn::itsUnitsCol
ScalarColumn< String > * itsUnitsCol
Definition ScalarQuantColumn.h:215
casacore::ScalarQuantColumn::itsUnitOut
Unit itsUnitOut
Definition ScalarQuantColumn.h:217
casacore::ScalarQuantColumn::getData
void getData(rownr_t rownr, Quantum< T > &q) const
Get the data without possible conversion.
casacore::ScalarQuantColumn::ScalarQuantColumn
ScalarQuantColumn()
The default constructor creates a null object.
casacore::ScalarQuantColumn::ScalarQuantColumn
ScalarQuantColumn(const ScalarQuantColumn< T > &that)
Copy constructor (copy semantics).
casacore::ScalarQuantColumn::ScalarQuantColumn
ScalarQuantColumn(const Table &tab, const String &columnName)
Create the ScalarQuantColumn from the specified table and column name.
casacore::ScalarQuantColumn::cleanUp
void cleanUp()
Deletes allocated memory etc.
casacore::ScalarQuantColumn::attach
void attach(const Table &tab, const String &columnName)
Attach a column to the object.
casacore::ScalarQuantColumn::isNull
Bool isNull() const
Test if the object is null.
Definition ScalarQuantColumn.h:189
casacore::ScalarQuantColumn::itsConvOut
Bool itsConvOut
Definition ScalarQuantColumn.h:219
casacore::ScalarQuantColumn::get
void get(rownr_t rownr, Quantum< T > &q, const Quantum< T > &other) const
Get the quantum in the specified row, converted to the unit in other.
casacore::ScalarQuantColumn::itsDataCol
ScalarColumn< T > * itsDataCol
Definition ScalarQuantColumn.h:213
casacore::ScalarQuantColumn::getColumn
std::shared_ptr< Quantum< Vector< T > > > getColumn(const Unit &unit="") const
Get the column as a Quantum<Vector<T> >.
casacore::ScalarQuantColumn::operator=
ScalarQuantColumn & operator=(const ScalarQuantColumn< T > &that)
Assignment makes no sense in a read only class.
casacore::ScalarQuantColumn::ScalarQuantColumn
ScalarQuantColumn(const Table &tab, const String &columnName, const Unit &)
Create the ScalarQuantColumn from the specified table and column name.
casacore::ScalarQuantColumn::throwIfNull
void throwIfNull() const
Throw an exception if the object is null.
casacore::ScalarQuantColumn::reference
void reference(const ScalarQuantColumn< T > &that)
Change the reference to another column.
casacore::ScalarQuantColumn::put
void put(rownr_t rownr, const Quantum< T > &q)
Put a quantum into the table.
casacore::ScalarQuantColumn::itsUnit
Unit itsUnit
Definition ScalarQuantColumn.h:205
casacore::ScalarQuantColumn::init
void init(const Table &tab, const String &columnName)
Initialize the ScalarQuantColumn from the specified table and column.
casacore::ScalarQuantColumn::get
void get(rownr_t rownr, Quantum< T > &q, const Unit &) const
Get the quantum in the specified row, converted to the given unit.
casacore::String
String: the storage and methods of handling collections of characters.
Definition String.h:223
casacore::Table
Definition Table.h:157
casacore::Unit
Definition Unit.h:187
casacore
this file contains all the compiler specific defines
Definition mainpage.dox:28
casacore::Bool
bool Bool
Define the standard types used by Casacore.
Definition aipstype.h:40
casacore::get
const T & get() const
Definition RecordField.h:143
casacore::rownr_t
uInt64 rownr_t
Define the type of a row number in a table.
Definition aipsxtype.h:44