/***************************************************************************
                          SIMPLY POWERFUL TOOLKIT (SPTK)
                          CMemoryDS.h  -  description
                             -------------------
    begin                : Mon Apr 17 2000
    copyright            : (C) 2000-2005 by Alexey S.Parshin
    email                : alexeyp@gmail.com
 ***************************************************************************/

/***************************************************************************
   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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

   Please report all bugs and problems to "alexeyp@gmail.com"
 ***************************************************************************/

#ifndef __CMEMORYDS_H__
#define __CMEMORYDS_H__

#include <sptk3/CFieldList.h>
#include <sptk3/CDataSource.h>
#include <sptk3/CException.h>
#include <vector>

/// @addtogroup gui GUI Classes
/// @{

/// @brief Base (memory) datasource
///
/// Class CMemoryDS implements a special case of the datasource when the data 
/// can be loaded all at once, in the datasource open() operation. It's a base class
/// for several actual datasources.
class CMemoryDS : public CDataSource  {
protected:
   std::vector<CFieldList *>  m_list;     ///< Internal list of the dataset records
   CFieldList         *m_current;         ///< Current record in the dataset.
   int                 m_currentIndex;    ///< The index of the current record.
   bool                m_eof;             ///< EOF flag for sequentual reading first(),next()..next().

protected:

   /// Default constructor is protected, to prevent creating of the instance of that class
   CMemoryDS() : CDataSource(), m_current(0L), m_currentIndex(-1) { }

public:

   /// Destructor
   virtual ~CMemoryDS() { close(); }

   /// Clears all the records
   virtual void clear();

   /// Field access by the field index, const version. 
   /// @param fieldIndex int, field index
   /// @returns field reference
   virtual const CField& operator [] (int fieldIndex) const;

   /// Field access by the field index, non-const version. 
   /// @param fieldIndex int, field index
   /// @returns field reference
   virtual CField&       operator [] (int fieldIndex);

   /// Field access by the field name, const version. 
   /// @param fieldName const char *, field name
   /// @returns field reference
   virtual const CField& operator [] (const char *fieldName) const;

   /// Field access by the field name, non-const version. 
   /// @param fieldName const char *, field name
   /// @returns field reference
   virtual CField&       operator [] (const char *fieldName);

   /// Returns user_data associated with the datasource.
   virtual void             *user_data() const { return m_current->user_data(); }

   /// Returns field count in the datasource. 
   /// @returns field count
   virtual unsigned          fieldCount() const;

   /// Returns record count in the datasource. 
   /// @returns record count
   virtual unsigned          recordCount() const;

   /// Reads the field by name from the datasource.
   /// @param fieldName const char *, field name
   /// @param fieldValue CVariant, field value 
   virtual bool              readField(const char *fieldName,CVariant& fieldValue);

   /// Writes the field by name from the datasource.
   /// @param fieldName const char *, field name
   /// @param fieldValue CVariant, field value 
   virtual bool              writeField(const char *fieldName,const CVariant& fieldValue);

   /// Opens the datasource. Implemented in derved class.
   virtual bool              open() { throw CException("Not implemented yet"); }

   /// Closes the datasource. 
   virtual bool              close();

   /// Moves to the first record of the datasource.
   virtual bool              first();

   /// Moves to the next record of the datasource.
   virtual bool              next();

   /// Moves to the prior record of the datasource.
   virtual bool              prior();

   /// Moves to the last record of the datasource.
   virtual bool              last();

   /// Finds the record by the record position (defined by record's user_data or key).
   virtual bool              find(CVariant position);

   /// Returns true if there are no more records in the datasource. Implemented in derved class.
   virtual bool              eof() const { return m_eof; }
};

/// @}

#endif
