TableIterProxy.h

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00001 //# TableIterProxy.h: Proxy for table iterator access
00002 //# Copyright (C) 1994,1995,1996,1999,2005
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 //# $Id$
00027 
00028 #ifndef TABLES_TABLEITERPROXY_H
00029 #define TABLES_TABLEITERPROXY_H
00030 
00031 
00032 //# Includes
00033 #include <casacore/casa/aips.h>
00034 #include <casacore/tables/Tables/TableIter.h>
00035 #include <casacore/casa/Arrays/Vector.h>
00036 
00037 namespace casacore { //# NAMESPACE CASACORE - BEGIN
00038 
00039 //# Forward Declarations
00040 class TableProxy;
00041 
00042 
00043 // <summary>
00044 // Proxy for table iterator access.
00045 // </summary>
00046 
00047 // <use visibility=export>
00048 
00049 // <reviewed reviewer="Paul Shannon" date="1995/09/15" tests="tgtable.g" demos="">
00050 // </reviewed>
00051 
00052 // <prerequisite>
00053 //# Classes you should understand before using this one.
00054 //   <li> class TableIterator
00055 // </prerequisite>
00056 
00057 // <etymology>
00058 // TableIterProxy holds a TableIterator object for the table
00059 // glish client.
00060 // </etymology>
00061 
00062 // <synopsis> 
00063 // TableIterProxy gives access to the table iterator functionality.
00064 // It is primarily meant to be used in classes that wrap access to it
00065 // from scripting languages (like Glish and Python).
00066 // However, it can also be used directly from other C++ code.
00067 //
00068 // A TableIterProxy object is usually created by class
00069 // <linkto class=TableProxy>TableProxy</linkto>.
00070 // </synopsis>
00071 
00072 // <example>
00073 // <srcblock>
00074 //    // Get a table proxy.
00075 //    TableProxy proxy("sometable");
00076 //    Vector<String> columns(1, "SOMECOL");
00077 //    TableIterProxy tgi (proxy, columns, "a", "q");
00078 //    TableProxy subTable;
00079 //    // Iterate through the table.
00080 //    while (tgi.next (subTable)) {
00081 //       ..use Table object subTable.table()
00082 //    }
00083 // </srcblock>
00084 // </example>
00085 
00086 class TableIterProxy
00087 {
00088 public:
00089   // Default constructor initializes to not open.
00090   // This constructor is only needed for the Block container.
00091   TableIterProxy();
00092 
00093   // Construct iterator for the given table column(s).
00094   // Order and sortType are case-insentive strings and only the first
00095   // character in it is important.
00096   // <br>order[0]=a means ascending; d means descending.
00097   // <br>sortType[0]=q means quicksort, i means insertion sort,
00098   //                 n means nosort, h means heapsort, otherwise parsort
00099   // <br>For each column an iteration interval can be given making it possible
00100   // to iterate in e.g. time chunks of 1 minute. Not given or zero means
00101   // no interval is given for that column, thus a normal comparison is done.
00102   // It can only be used for numerical columns (not complex).
00103   // However, if for a string column the interbval is set to non-zero, it
00104   // means that case-insensitive comparison will be used.
00105   TableIterProxy (const TableProxy& tab, const Vector<String>& columns,
00106                   const String& order, const String& sortType,
00107                   const Vector<Double>& intervals = Vector<Double>());
00108 
00109   // Copy constructor (copy semantics).
00110   TableIterProxy (const TableIterProxy&);
00111 
00112   ~TableIterProxy();
00113 
00114   // Assignment (copy semantics).
00115   TableIterProxy& operator= (const TableIterProxy&);
00116 
00117   // Is the internal iterator object null?
00118   Bool isNull() const
00119     { return iter_p.isNull(); }
00120 
00121   // Get the TableIterator object.
00122   const TableIterator& iterator() const
00123     { return iter_p; }
00124 
00125   // Get the next subtable and return it in the TableProxy argument.
00126   // When no more subtables are available, it returns False.
00127   Bool nextPart (TableProxy& table);
00128 
00129   // Iterate to the next part (for Python use).
00130   // An IterError exception is thrown at the end of the loop.
00131   TableProxy next();
00132 
00133   // Reset the iterator (for Python use).
00134   void reset();
00135 
00136 
00137 private:
00138   // Make an iterator where iteration intervals may have been given.
00139   void makeStepIter (const Table& tab,
00140                      const Block<String>& columns,
00141                      const Vector<Double>& iterSteps,
00142                      TableIterator::Order order,
00143                      TableIterator::Option sortType);
00144 
00145   //# Data members
00146   TableIterator iter_p;
00147   Bool          firstTime_p;           //# True = first time
00148 };
00149 
00150 
00151 } //# NAMESPACE CASACORE - END
00152 
00153 
00154 #endif
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