ExprUDFNode.h

Go to the documentation of this file.

// # ExprUDFNode.h: Class representing a scalar UDF in select expression
// # Copyright (C) 2010
// # 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 TABLES_EXPRUDFNODE_H
#define TABLES_EXPRUDFNODE_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/tables/TaQL/ExprNodeRep.h>
#include <casacore/tables/TaQL/UDFBase.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward Declarations
class TableExprNodeSet;
 
// <summary>
// Class representing a scalar UDF in select expression
// </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="">
// </reviewed>
// <prerequisite>
// # Classes you should understand before using this one.
//   <li> <linkto class=TableExprNodeMulti>TableExprNodeMulti</linkto>
// </prerequisite>
 
// <synopsis>
// This class represents a function in a table select tree.
// The <src>rownumber</src> function is represented by class
// <linkto class=TableExprNodeRownr>TableExprNodeRownr</linkto>.
// The <src>rowid</src> function is represented by class
// <linkto class=TableExprNodeRowid>TableExprNodeRowid</linkto>.
// The <src>rand</src> function is represented by class
// <linkto class=TableExprNodeRandom>TableExprNodeRandom</linkto>.
// <p>
// When one wants to add a function to the table selection grammar,
// the following has to be done:
// <ul>
//  <li> Add the function to the enum below.
//  <li> Implement the function in the get functions in ExprFuncNode(Array).cc.
//  <li> Implement the function in the checkOperands in ExprFuncNode.cc.
//  <li> Declare and define the function in ExprNode.h (for C++ binding).
//  <li> Add the function to findFunc in TableParse.cc (for TaQL).
// </ul>
// </synopsis>
 
class TableExprUDFNode : public TableExprNodeMulti {
 public:
  // Constructor
  TableExprUDFNode(const std::shared_ptr<UDFBase>& udf, const TableExprInfo&,
                   const TableExprNodeSet& source);
 
  // Destructor
  ~TableExprUDFNode() override = default;
 
  // Is the UDF an aggregate function?
  Bool isAggregate() const override { return itsUDF->isAggregate(); }
 
  // Get the table info.
  TableExprInfo getTableInfo() const override;
 
  // Flatten the node tree by adding the node and its children to the vector.
  void flattenTree(std::vector<TableExprNodeRep*>&) override;
 
  // Do not apply the selection.
  void disableApplySelection() override;
 
  // If needed, let the UDF re-create column objects for a selection of rows.
  // It calls the function recreateColumnObjects.
  void applySelection(const Vector<rownr_t>& rownrs) override;
 
  // UDFs do not need a TableExprGroupFuncBase,
  // so TableExprGroupNull is returned.
  std::shared_ptr<TableExprGroupFuncBase> makeGroupAggrFunc() override;
 
  // Functions to get the desired result of a function
  // <group>
  Bool getBool(const TableExprId& id) override;
  Int64 getInt(const TableExprId& id) override;
  Double getDouble(const TableExprId& id) override;
  DComplex getDComplex(const TableExprId& id) override;
  String getString(const TableExprId& id) override;
  TaqlRegex getRegex(const TableExprId& id) override;
  MVTime getDate(const TableExprId& id) override;
  // </group>
 
 private:
  TableExprInfo itsTableInfo;
  std::shared_ptr<UDFBase> itsUDF;
};
 
}  // namespace casacore
 
#endif