Select.h

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/*
 * (C) Copyright 1996-2012 ECMWF.
 * 
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. 
 * In applying this licence, ECMWF does not waive the privileges and immunities 
 * granted to it by virtue of its status as an intergovernmental organisation nor
 * does it submit to any jurisdiction.
 */
 
/// @author Piotr Kuchta
/// @author
/// @date April 2010
 
#ifndef odc_Select_H
#define odc_Select_H
 
#ifdef SWIGPYTHON
#include <Python.h>
#endif
 
#include "odc/IteratorProxy.h"
#include "odc/SelectIterator.h"
#include "eckit/sql/SQLSession.h"
 
namespace eckit { class PathName; }
namespace eckit { class DataHandle; }
 
namespace odc {
 
//----------------------------------------------------------------------------------------------------------------------
 
class Select
{
public:
    typedef IteratorProxy<SelectIterator,Select,const double> iterator;
    typedef iterator::Row row;
 
    Select(const std::string& selectStatement="", bool manageOwnBuffer=true);
    Select(const std::string& selectStatement, eckit::DataHandle& dh, bool manageOwnBuffer=true);
    Select(const std::string& selectStatement, const std::string& path, bool manageOwnBuffer=true);
 
    // This only exists to disambiguate const char* --> std::string rather than to bool.
    Select(const std::string& selectStatement, const char* path, bool manageOwnBuffer=true);
 
    virtual ~Select();
 
#ifdef SWIGPYTHON
    iterator __iter__() { return iterator(createSelectIterator(selectStatement_)); }
#endif
 
    eckit::sql::SQLDatabase& database();
 
    iterator begin();
    const iterator end();
 
    SelectIterator* createSelectIterator(const std::string&);
 
private:
 
 
    friend class odc::IteratorProxy<odc::SelectIterator, odc::Select, const double>;
 
    std::unique_ptr<eckit::DataHandle> ownDH_;
 
//  std::istream* istream_;
 
    std::string selectStatement_;
    std::string delimiter_;
 
    eckit::sql::SQLSession session_;
 
    // This is horrible, but the TextReader, and any stream based iteraton, can only
    // iterate once, so we MUST NOT create two iterators if begin() is called twice.
    bool initted_;
    iterator it_;
};
 
//----------------------------------------------------------------------------------------------------------------------
 
} // namespace odc
 
#endif