MemoryTable.h

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00001 //# MemoryTable.h: Class for a table held in memory
00002 //# Copyright (C) 2003
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_MEMORYTABLE_H
00029 #define TABLES_MEMORYTABLE_H
00030 
00031 
00032 //# Includes
00033 #include <casacore/casa/aips.h>
00034 #include <casacore/tables/Tables/BaseTable.h>
00035 #include <casacore/casa/BasicSL/String.h>
00036 #include <casacore/casa/Arrays/Vector.h>
00037 
00038 namespace casacore { //# NAMESPACE CASACORE - BEGIN
00039 
00040 //# Forward Declarations
00041 class SetupNewTable;
00042 class ColumnSet;
00043 class TableLockData;
00044 
00045 
00046 // <summary>
00047 // Class for a table held in memory
00048 // </summary>
00049 
00050 // <use visibility=local>
00051 
00052 // <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="">
00053 // </reviewed>
00054 
00055 // <prerequisite>
00056 //# Classes you should understand before using this one.
00057 //   <li> BaseTable
00058 // </prerequisite>
00059 
00060 // <synopsis> 
00061 // MemoryTable holds all its data in memory.
00062 // It means that the data is not persistent. However, it can be copied to
00063 // another table to make the data persistent.
00064 // Furthermore it is a table as all other tables, so all table functions
00065 // can be applied to it. Some functions (e.g. lock) won't do anything.
00066 // Also all table operations like sorting, selecting, and iterating can
00067 // be used.
00068 //
00069 // The constructor accepts a SetupNewTable object which can contain
00070 // bindings of columns to any data manager. All bindings to storage
00071 // managers will be replaced by a binding to the memory based storage
00072 // manager <linkto class=MemoryStMan>MemoryStMan</linkto>. Also all
00073 // unbound columns will be bound to MemoryStMan.
00074 // Thus it is still possible that a column is bound to a virtual column
00075 // engine like <linkto class=CompressComplex>CompressComplex</linkto>.
00076 // </synopsis> 
00077 
00078 //# <todo asof="$DATE:$">
00079 //# </todo>
00080 
00081 
00082 class MemoryTable : public BaseTable
00083 {
00084 public:
00085 
00086   // Create the table in memory using the definitions in the
00087   // SetupNewTable object.
00088   MemoryTable (SetupNewTable&, uInt nrrow, Bool initialize);
00089 
00090   // The destructor deletes all data.
00091   virtual ~MemoryTable();
00092 
00093   // Try to reopen the table (the underlying one) for read/write access.
00094   // It does nothing.
00095   virtual void reopenRW();
00096 
00097   // Is the table stored in big or little endian format?
00098   // It returns the endian format of the machine.
00099   virtual Bool asBigEndian() const;
00100 
00101   // Get the storage option used for the table.
00102   virtual const StorageOption& storageOption() const;
00103 
00104   // Is the table in use (i.e. open) in another process?
00105   // It always returns False.
00106   virtual Bool isMultiUsed (Bool checkSubTable) const;
00107 
00108   // Get the locking info.
00109   // It returns PermanentLocking.
00110   virtual const TableLock& lockOptions() const;
00111 
00112   // Merge the given lock info with the existing one.
00113   // It does nothing.
00114   virtual void mergeLock (const TableLock& lockOptions);
00115 
00116   // Has this process the read or write lock, thus can the table
00117   // be read or written safely?
00118   // It always returns True.
00119   virtual Bool hasLock (FileLocker::LockType) const;
00120 
00121   // Locking the table is a no-op.
00122   virtual Bool lock (FileLocker::LockType, uInt nattempts);
00123 
00124   // Unlocking the table is a no-op.
00125   virtual void unlock();
00126 
00127   // Flushing the table is a no-op.
00128   virtual void flush (Bool fsync, Bool recursive);
00129 
00130   // Resyncing the Table is a no-op.
00131   virtual void resync();
00132 
00133   // Get the modify counter. It always returns 0.
00134   virtual uInt getModifyCounter() const;
00135 
00136   // Test if the table is opened as writable. It always returns True.
00137   virtual Bool isWritable() const;
00138 
00139   // Copy the table and all its subtables.
00140   // It copies the contents of each row to get a real copy.
00141   // <group>
00142   virtual void copy (const String& newName, int tableOption) const;
00143   virtual void deepCopy (const String& newName,
00144                          const Record& dataManagerInfo,
00145                          const StorageOption&,
00146                          int tableOption, Bool, int endianFormat,
00147                          Bool noRows) const;
00148   // </group>
00149 
00150   // Rename the table. The tableOption is ignored.
00151   virtual void rename (const String& newName, int tableOption);
00152 
00153   // Get the table type (Table::Memory).
00154   virtual int tableType() const;
00155 
00156   // Get the actual table description.
00157   virtual TableDesc actualTableDesc() const;
00158 
00159   // Get the data manager info.
00160   virtual Record dataManagerInfo() const;
00161 
00162   // Get readonly access to the table keyword set.
00163   virtual TableRecord& keywordSet();
00164 
00165   // Get read/write access to the table keyword set.
00166   virtual TableRecord& rwKeywordSet();
00167 
00168   // Write the TableInfo object. It does not do anything.
00169   virtual void flushTableInfo();
00170 
00171   // Get a column object using its index.
00172   virtual BaseColumn* getColumn (uInt columnIndex) const;
00173 
00174   // Get a column object using its name.
00175   virtual BaseColumn* getColumn (const String& columnName) const;
00176 
00177   // Test if it is possible to add a row to this table (yes).
00178   virtual Bool canAddRow() const;
00179 
00180   // Add one or more rows and possibly initialize them.
00181   // This will fail for tables not supporting addition of rows.
00182   virtual void addRow (uInt nrrow = 1, Bool initialize = True);
00183 
00184   // Test if it is possible to remove a row from this table (yes).
00185   virtual Bool canRemoveRow() const;
00186 
00187   // Remove the given row.
00188   virtual void removeRow (uInt rownr);
00189 
00190   // Add a column to the table.
00191   // If the DataManager is not a virtual engine, MemoryStMan will be used.
00192   // The last Bool argument is not used in MemoryTable, but can be used in
00193   // other classes derived from BaseTable.
00194   // <group>
00195   virtual void addColumn (const ColumnDesc& columnDesc, Bool addToParent);
00196   virtual void addColumn (const ColumnDesc& columnDesc,
00197                           const String& dataManager, Bool byName,
00198                           Bool addToParent);
00199   virtual void addColumn (const ColumnDesc& columnDesc,
00200                           const DataManager& dataManager, Bool addToParent);
00201   virtual void addColumn (const TableDesc& tableDesc,
00202                           const DataManager& dataManager, Bool addToParent);
00203   // </group>
00204 
00205   // Test if columns can be removed (yes).
00206   virtual Bool canRemoveColumn (const Vector<String>& columnNames) const;
00207 
00208   // Remove columns.
00209   virtual void removeColumn (const Vector<String>& columnNames);
00210 
00211   // Test if a column can be renamed (yes).
00212   virtual Bool canRenameColumn (const String& columnName) const;
00213 
00214   // Rename a column.
00215   virtual void renameColumn (const String& newName, const String& oldName);
00216 
00217   // Rename a hypercolumn.
00218   virtual void renameHypercolumn (const String& newName,
00219                                   const String& oldName);
00220 
00221   // Find the data manager with the given name or for the given column.
00222   // There is only one storage manager (MemoryStMan) with name MSM.
00223   virtual DataManager* findDataManager (const String& name,
00224                                         Bool byColumn) const;
00225 
00226 
00227 private:
00228   ColumnSet*     colSetPtr_p;        //# pointer to set of columns
00229   TableLockData* lockPtr_p;          //# pointer to lock object
00230 
00231   // Copy constructor is forbidden, because copying a table requires
00232   // some more knowledge (like table name of result).
00233   // Declaring it private, makes it unusable.
00234   MemoryTable (const MemoryTable&);
00235 
00236   // Assignment is forbidden, because copying a table requires
00237   // some more knowledge (like table name of result).
00238   // Declaring it private, makes it unusable.
00239   MemoryTable& operator= (const MemoryTable&);
00240 
00241   // Setup the main parts of the object.
00242   // <br>Create the initial name map from the table description.
00243   // This map maps a name to the name in the original table.
00244   // A rename might change the map.
00245   // <br>Create the RefColumn objects.
00246   // <br>Create the initial TableInfo as a copy of the original BaseTable.
00247   void setup (BaseTable* btp);
00248 };
00249 
00250 
00251 
00252 } //# NAMESPACE CASACORE - END
00253 
00254 #endif
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