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RecordTransformable.h
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//# RecordTransformable.h: Interface class for converting to/from records
//# Copyright (C) 1998,1999,2003
//# 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 CASA_RECORDTRANSFORMABLE_H
#define CASA_RECORDTRANSFORMABLE_H
#include <casacore/casa/aips.h>
namespace casacore { //# NAMESPACE CASACORE - BEGIN
class String;
class RecordInterface;
// <summary>Interface class for converting to/from records</summary>
// <use visibility=export>
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="tRecordTransformable">
// </reviewed>
// <prerequisite>
// <li> <linkto class="RecordInterface">RecordInterface</linkto>
// </prerequisite>
//
// <etymology>
// This class defines the interface that a class should use if the can be
// transformed into a record representation.
// </etymology>
//
// <synopsis>
// This abstract base class is intended to be publicly inherited by classes
// that contain functions which can represent the object as a record (these
// functions should be called <src>toRecord</src> and
// <src>fromRecord</src>). Examples of records are:
// <ul>
// <li> <linkto class="Record">Record</linkto>
// <li> <linkto class="TableRecord">TableRecord</linkto>
// </ul>
//
// This interface defines two functions that convert between a RecordInterface
// and the class that inherits these functions. These functions are often used
// to parse input that is beyond the programs control e.g. user input from
// glish or Table records that may have been generated elsewhere. Hence
// exceptions should not thrown be thrown by these functions. Instead the
// function should return False and append an error message to the supplied
// String when the transformation cannot be accomplished.
//
// <note role=warning>
// Converting to/from a GlishRecord requires an extra step.
// First a Record should be used which can thereafter be converted to/from
// a GlishRecord using the appropriate GlishRecord functions.
// </note>
// </synopsis>
//
// <example>
// The following example prints out a class using its record representation.
// This example is in the file tRecordTransformable.cc
// <srcblock>
// void printAsRecord(const RecordTransformable & myClass) {
// String errorMessage;
// Record rec;
// if (!myClass.toRecord(errorMessage, rec)) {
// cout << "Cannot convert class to a Record. The reason is:" << endl;
// cout << errorMessage << endl;
// } else {
// cout << rec.ndefined() << endl;
// }
// }
// </srcblock>
// </example>
//
// <motivation>
// This class was designed to standardise the function interface for converting
// between an object and its record representation.
// </motivation>
//
// <todo asof="1998/03/30">
// <li> Nothing I hope!
// </todo>
class RecordTransformable
{
public:
// The destructor must be virtual so that the destructor of derived classes
// is actually used.
virtual ~RecordTransformable();
// Convert the class to an Record representation. The input record may
// already contain fields and these fields may be silently overridden. New
// fields may be added to the input Record. If the transformation succeeds
// then the error String is unchanged and the function returns
// True. Otherwise the function returns False and appends an error message to
// the supplied String giving the reason why the conversion failed.
virtual Bool toRecord(String & error, RecordInterface & outRecord) const = 0;
// Initialise the class from a Record representation. The input record should
// contain the fields that are required by the class. Other fields will be
// ignored. If the transformation succeeds then the error String is unchanged
// and the function returns True. Otherwise the function returns False and
// appends an error message to the supplied String giving the reason why the
// conversion failed.
virtual Bool fromRecord(String & error, const RecordInterface & inRecord) =0;
// Initialise the class from a String representation. A string cannot
// contain enough information for many objects. Hence the default
// implementation of this class returns False, indicating that the class
// could not be initialised and an error message is appended to the supplied
// string. If the class can be initialised from a string then this function
// should be overridden.
virtual Bool fromString(String & error, const String & inString);
// Specify the identification of the record (e.g. 'meas', 'quant'). The
// default implementation returns a empty string.
virtual const String &ident() const;
};
} //# NAMESPACE CASACORE - END
#endif
casacore::RecordTransformable
Definition RecordTransformable.h:104
casacore::RecordTransformable::fromString
virtual Bool fromString(String &error, const String &inString)
Initialise the class from a String representation.
casacore::RecordTransformable::fromRecord
virtual Bool fromRecord(String &error, const RecordInterface &inRecord)=0
Initialise the class from a Record representation.
casacore::RecordTransformable::toRecord
virtual Bool toRecord(String &error, RecordInterface &outRecord) const =0
Convert the class to an Record representation.
casacore::RecordTransformable::ident
virtual const String & ident() const
Specify the identification of the record (e.g.
casacore::RecordTransformable::~RecordTransformable
virtual ~RecordTransformable()
The destructor must be virtual so that the destructor of derived classes is actually used.
casacore::String
String: the storage and methods of handling collections of characters.
Definition String.h:223
casacore
this file contains all the compiler specific defines
Definition mainpage.dox:28
casacore::RecordInterface
RecordInterface()
The default constructor creates an empty record with a variable structure.
casacore::Bool
bool Bool
Define the standard types used by Casacore.
Definition aipstype.h:40