MSDataDescColumns.h

Go to the documentation of this file.

// # MSDataDescColumns.h: provides easy access to MSDataDescription columns
// # Copyright (C) 1996,1999,2000
// # 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 MS_MSDATADESCCOLUMNS_H
#define MS_MSDATADESCCOLUMNS_H
 
#include <casacore/casa/aips.h>
#include <casacore/tables/Tables/ScalarColumn.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
class MSDataDescription;
 
// <summary>
// A class to provide easy access to MSDataDescription columns
// </summary>
 
// <use visibility=export>
 
// <reviewed reviewer="Bob Garwood" date="1997/02/01" tests="" demos="">
// </reviewed>
 
// <prerequisite>
//   <li> MSDataDesc
//   <li> ScalarColumn
// </prerequisite>
//
// <etymology>
// MSDataDescColumns stands for MeasurementSet DataDescription Table
// columns.
// </etymology>
//
// <synopsis>
// This class provides access to the columns in the MSDataDesc Table,
// it does the declaration of all the Scalar and ArrayColumns with the
// correct types, so the application programmer doesn't have to
// worry about getting those right. There is an access function
// for every predefined column. Access to non-predefined columns will still
// have to be done with explicit declarations.
// See <linkto class=MSColumns> MSColumns</linkto> for an example.
// <note role=warning> The Table that is used to construct this class must not
// be destroyed (or go out of scope) before this class does. Otherwise the
// scalar and array columns use by this class will be left dangling.</note>
// </synopsis>
//
// <motivation>
// See <linkto class=MSColumns> MSColumns</linkto> for the motivation.
// </motivation>
 
class MSDataDescColumns {
 public:
  // Create a columns object that accesses the data in the specified Table
  MSDataDescColumns(const MSDataDescription& msDataDesc);
 
  // The destructor does nothing special
  ~MSDataDescColumns();
 
  // Access to required columns
  // <group>
  ScalarColumn<Bool>& flagRow() { return flagRow_p; }
  ScalarColumn<Int>& polarizationId() { return polarizationId_p; }
  ScalarColumn<Int>& spectralWindowId() { return spectralWindowId_p; }
  // </group>
 
  // Const access to required columns
  // <group>
  const ScalarColumn<Bool>& flagRow() const { return flagRow_p; }
  const ScalarColumn<Int>& polarizationId() const { return polarizationId_p; }
  const ScalarColumn<Int>& spectralWindowId() const { return spectralWindowId_p; }
  // </group>
 
  // Access to optional columns
  // <group>
  ScalarColumn<Int>& lagId() { return lagId_p; }
  // </group>
 
  // Const access to optional columns
  // <group>
  const ScalarColumn<Int>& lagId() const { return lagId_p; }
  // </group>
 
  // Convenience function that returns the number of rows in any of the columns
  rownr_t nrow() const { return flagRow_p.nrow(); }
 
  // returns the last row that contains the specified entries in the
  // SPECTRAL_WINDOW_ID & POLARIZATION_ID columns. Returns -1 if no match could
  // be found. Flagged rows can never match. If tryRow is non-negative, then
  // that row is tested to see if it matches before any others are
  // tested. Setting tryRow to a positive value greater than the table length
  // will throw an exception (AipsError).
  Int64 match(uInt spwId, uInt polId, Int64 tryRow = -1);
 
 protected:
  // # default constructor creates a object that is not usable. Use the attach
  // # function correct this.
  MSDataDescColumns();
 
  // # attach all the columns in the supplied table to this object
  void attach(const MSDataDescription& msDataDesc);
 
 private:
  // # Make the assignment operator and the copy constructor private to prevent
  // # any compiler generated one from being used.
  MSDataDescColumns(const MSDataDescColumns&);
  MSDataDescColumns& operator=(const MSDataDescColumns&);
 
  // # attach optional columns in the supplied Table (if they exist)
  void attachOptionalCols(const MSDataDescription& msDataDesc);
 
  // # required columns
  ScalarColumn<Bool> flagRow_p;
  ScalarColumn<Int> polarizationId_p;
  ScalarColumn<Int> spectralWindowId_p;
  // # optional columns
  ScalarColumn<Int> lagId_p;
};
 
// # Define the RO version for backward compatibility.
typedef MSDataDescColumns ROMSDataDescColumns;
 
}  // namespace casacore
 
#endif