TableExprId.h

Go to the documentation of this file.
00001 //# TableExprId.h: The identification of a TaQL selection subject
00002 //# Copyright (C) 2000
00003 //# Associated Universities, Inc. Washington DC, USA.
00004 //#
00005 //# This library is free software; you can redistribute it and/or modify it
00006 //# under the terms of the GNU Library General Public License as published by
00007 //# the Free Software Foundation; either version 2 of the License, or (at your
00008 //# option) any later version.
00009 //#
00010 //# This library is distributed in the hope that it will be useful, but WITHOUT
00011 //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
00012 //# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
00013 //# License for more details.
00014 //#
00015 //# You should have received a copy of the GNU Library General Public License
00016 //# along with this library; if not, write to the Free Software Foundation,
00017 //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
00018 //#
00019 //# Correspondence concerning AIPS++ should be addressed as follows:
00020 //#        Internet email: aips2-request@nrao.edu.
00021 //#        Postal address: AIPS++ Project Office
00022 //#                        National Radio Astronomy Observatory
00023 //#                        520 Edgemont Road
00024 //#                        Charlottesville, VA 22903-2475 USA
00025 //#
00026 //#
00027 //# $Id$
00028 
00029 
00030 #ifndef TABLES_TABLEEXPRID_H
00031 #define TABLES_TABLEEXPRID_H
00032 
00033 //# Includes
00034 #include <casacore/casa/aips.h>
00035 #include <casacore/casa/stdvector.h>
00036 
00037 namespace casacore { //# NAMESPACE CASACORE - BEGIN
00038 
00039 //# Forward Declarations
00040 class RecordInterface;
00041 class TableExprData;
00042 
00043 // <summary>
00044 // The identification of a TaQL selection subject.
00045 // </summary>
00046 
00047 // <use visibility=export>
00048 
00049 // <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="">
00050 // </reviewed>
00051 
00052 // <prerequisite>
00053 //   <li> <linkto class="TableExprNode">TableExprNode</linkto>.
00054 // </prerequisite>
00055 
00056 // <synopsis>
00057 // This class provides the user the ability to identify the data objects
00058 // to test in a TaQL expression. In this way a TaQL expression is not
00059 // limited to tables, but can be used for any set of data.
00060 // Three types are available:
00061 // <ol>
00062 //  <li> A row number giving the row to test in a table.
00063 //       It also contains a sequence number (0..n) which is used to get the
00064 //       result calculated by aggregate functions.
00065 //  <li> A <linkto class=RecordInterface>RecordInterface</linkto>
00066 //       object giving the record to test.
00067 //  <li> A <linkto class=TableExprData>TableExprData</linkto>
00068 //       object giving the abstract base class of an object holding
00069 //       the data to test. In this way any data can be used.
00070 // </ol>
00071 // The TaQL expression must be setup with this in mind by constructing
00072 // the appropriate <linkto class=TableExprNode>TableExprNode</linkto>
00073 // leaf objects.
00074 // <br>
00075 // When used for tables, the function <linkto class=Table>Table::col</linkto>
00076 // should be used to create the <src>TableExprNode</src> objects for the
00077 // table columns to be used in the expression.
00078 // <br>
00079 // For the other cases class
00080 // <linkto class=TableExprNodeRecordField>TableExprNodeRecordField</linkto>
00081 // has to be used to know the index of the fields in the expression.
00082 // It uses a record (description) for this purpose.
00083 // </synopsis>
00084 
00085 // <example>
00086 // <srcblock>
00087 // </srcBlock>
00088 // </example>
00089 
00090 // <motivation>
00091 // This class makes it possible that TaQL can be used in a very versatile way.
00092 // </motivation>
00093 
00094 //# <todo asof="1996/03/12">
00095 //# </todo>
00096 
00097 
00098 class TableExprId
00099 {
00100 public:
00101     // Default constructor sets rownr to -1.
00102     TableExprId();
00103 
00104     // Construct it from a row number.
00105     TableExprId (uInt rowNumber);
00106 
00107     // Construct it from a Record object.
00108     TableExprId (const RecordInterface&);
00109 
00110     // Construct it from pointers to data.
00111     TableExprId (const TableExprData& data);
00112 
00113     ~TableExprId()
00114     {}
00115 
00116     // Is the id given by row number?
00117     Bool byRow() const;
00118 
00119     // Is the id given as a RecordInterface?
00120     Bool byRecord() const;
00121 
00122     // Is the id given as a TableExprData?
00123     Bool byData() const;
00124 
00125     // Get the row number.
00126     Int64 rownr() const;
00127 
00128     // Get the Record reference.
00129     const RecordInterface& record() const;
00130 
00131     // Get the data reference.
00132     const TableExprData& data() const;
00133     // Set the row number.
00134 
00135     void setRownr (uInt rownr);
00136 
00137     // Set the record.
00138     void setRecord (const RecordInterface&);
00139 
00140 private:
00141     Int                          type_p;
00142     union {
00143       Int64                      row_p;
00144       const RecordInterface*     record_p;
00145       const TableExprData*       data_p;
00146     };
00147 };
00148 
00149 
00150 
00151 inline TableExprId::TableExprId()
00152   : type_p (0),
00153     row_p  (-1)
00154 {}
00155 
00156 inline TableExprId::TableExprId (uInt rowNumber)
00157   : type_p (0),
00158     row_p  (rowNumber)
00159 {}
00160 
00161 inline TableExprId::TableExprId (const RecordInterface& record)
00162   : type_p   (-1),
00163     record_p (&record)
00164 {}
00165 
00166 inline TableExprId::TableExprId (const TableExprData& data)
00167   : type_p (-2),
00168     data_p (&data)
00169 {}
00170 
00171 inline Int64 TableExprId::rownr() const
00172 {
00173     return row_p;
00174 }
00175 
00176 inline const RecordInterface& TableExprId::record() const
00177 {
00178     return *record_p;
00179 }
00180 
00181 inline const TableExprData& TableExprId::data() const
00182 {
00183     return *data_p;
00184 }
00185 
00186 inline void TableExprId::setRownr (uInt rownr)
00187 {
00188     row_p = rownr;
00189 }
00190 
00191 inline void TableExprId::setRecord (const RecordInterface& record)
00192 {
00193     record_p = &record;
00194 }
00195 
00196 inline Bool TableExprId::byRow() const
00197 {
00198     return type_p >= 0;
00199 }
00200 
00201 inline Bool TableExprId::byRecord() const
00202 {
00203     return type_p == -1;
00204 }
00205 
00206 inline Bool TableExprId::byData() const
00207 {
00208     return type_p == -2;
00209 }
00210 
00211 
00212 } //# NAMESPACE CASACORE - END
00213 
00214 #endif
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Defines

Generated on 31 Aug 2016 for casa by  doxygen 1.6.1