poco/Data/include/Poco/Data/BulkExtraction.h
2015-04-06 17:34:48 +01:00

278 lines
7.0 KiB
C++

//
// BulkExtraction.h
//
// $Id: //poco/Main/Data/include/Poco/Data/BulkExtraction.h#9 $
//
// Library: Data
// Package: DataCore
// Module: BulkExtraction
//
// Definition of the BulkExtraction class.
//
// Copyright (c) 2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Data_BulkExtraction_INCLUDED
#define Data_BulkExtraction_INCLUDED
#include "Poco/Data/Data.h"
#include "Poco/Data/AbstractExtraction.h"
#include "Poco/Data/Bulk.h"
#include "Poco/Data/Preparation.h"
#include <vector>
namespace Poco {
namespace Data {
template <class C>
class BulkExtraction: public AbstractExtraction
/// Specialization for bulk extraction of values from a query result set.
/// Bulk extraction support is provided only for following STL containers:
/// - std::vector
/// - std::deque
/// - std::list
{
public:
typedef C ValType;
typedef typename C::value_type CValType;
typedef SharedPtr<ValType> ValPtr;
typedef BulkExtraction<ValType> Type;
typedef SharedPtr<Type> Ptr;
BulkExtraction(C& result, Poco::UInt32 limit, const Position& pos = Position(0)):
AbstractExtraction(limit, pos.value(), true),
_rResult(result),
_default()
{
if (static_cast<Poco::UInt32>(result.size()) != limit)
result.resize(limit);
}
BulkExtraction(C& result, const CValType& def, Poco::UInt32 limit, const Position& pos = Position(0)):
AbstractExtraction(limit, pos.value(), true),
_rResult(result),
_default(def)
{
if (static_cast<Poco::UInt32>(result.size()) != limit)
result.resize(limit);
}
virtual ~BulkExtraction()
{
}
std::size_t numOfColumnsHandled() const
{
return TypeHandler<C>::size();
}
std::size_t numOfRowsHandled() const
{
return _rResult.size();
}
std::size_t numOfRowsAllowed() const
{
return getLimit();
}
bool isNull(std::size_t row) const
{
try
{
return _nulls.at(row);
}catch (std::out_of_range& ex)
{
throw RangeException(ex.what());
}
}
std::size_t extract(std::size_t col)
{
AbstractExtractor::Ptr pExt = getExtractor();
TypeHandler<C>::extract(col, _rResult, _default, pExt);
typename C::iterator it = _rResult.begin();
typename C::iterator end = _rResult.end();
for (int row = 0; it !=end; ++it, ++row)
{
_nulls.push_back(isValueNull(*it, pExt->isNull(col, row)));
}
return _rResult.size();
}
virtual void reset()
{
}
AbstractPreparation::Ptr createPreparation(AbstractPreparator::Ptr& pPrep, std::size_t col)
{
Poco::UInt32 limit = getLimit();
if (limit != _rResult.size()) _rResult.resize(limit);
pPrep->setLength(limit);
pPrep->setBulk(true);
return new Preparation<C>(pPrep, col, _rResult);
}
protected:
const C& result() const
{
return _rResult;
}
private:
C& _rResult;
CValType _default;
std::deque<bool> _nulls;
};
template <class C>
class InternalBulkExtraction: public BulkExtraction<C>
/// Container Data Type specialization extension for extraction of values from a query result set.
///
/// This class is intended for PocoData internal use - it is used by StatementImpl
/// to automatically create internal BulkExtraction in cases when statement returns data and no external storage
/// was supplied. It is later used by RecordSet to retrieve the fetched data after statement execution.
/// It takes ownership of the Column pointer supplied as constructor argument. Column object, in turn
/// owns the data container pointer.
///
/// InternalBulkExtraction objects can not be copied or assigned.
{
public:
typedef C ValType;
typedef typename C::value_type CValType;
typedef SharedPtr<ValType> ValPtr;
typedef InternalBulkExtraction<ValType> Type;
typedef SharedPtr<Type> Ptr;
InternalBulkExtraction(C& result,
Column<C>* pColumn,
Poco::UInt32 limit,
const Position& pos = Position(0)):
BulkExtraction<C>(result, CValType(), limit, pos),
_pColumn(pColumn)
/// Creates InternalBulkExtraction.
{
}
~InternalBulkExtraction()
/// Destroys InternalBulkExtraction.
{
delete _pColumn;
}
void reset()
{
_pColumn->reset();
}
const CValType& value(int index) const
{
try
{
return BulkExtraction<C>::result().at(index);
}
catch (std::out_of_range& ex)
{
throw RangeException(ex.what());
}
}
bool isNull(std::size_t row) const
{
return BulkExtraction<C>::isNull(row);
}
const Column<C>& column() const
{
return *_pColumn;
}
private:
InternalBulkExtraction();
InternalBulkExtraction(const InternalBulkExtraction&);
InternalBulkExtraction& operator = (const InternalBulkExtraction&);
Column<C>* _pColumn;
};
namespace Keywords {
template <typename T>
AbstractExtraction::Ptr into(std::vector<T>& t, const Bulk& bulk, const Position& pos = Position(0))
/// Convenience function to allow for a more compact creation of an extraction object
/// with std::vector bulk extraction support.
{
return new BulkExtraction<std::vector<T> >(t, bulk.size(), pos);
}
template <typename T>
AbstractExtraction::Ptr into(std::vector<T>& t, BulkFnType, const Position& pos = Position(0))
/// Convenience function to allow for a more compact creation of an extraction object
/// with std::vector bulk extraction support.
{
Poco::UInt32 size = static_cast<Poco::UInt32>(t.size());
if (0 == size) throw InvalidArgumentException("Zero length not allowed.");
return new BulkExtraction<std::vector<T> >(t, size, pos);
}
template <typename T>
AbstractExtraction::Ptr into(std::deque<T>& t, const Bulk& bulk, const Position& pos = Position(0))
/// Convenience function to allow for a more compact creation of an extraction object
/// with std::deque bulk extraction support.
{
return new BulkExtraction<std::deque<T> >(t, bulk.size(), pos);
}
template <typename T>
AbstractExtraction::Ptr into(std::deque<T>& t, BulkFnType, const Position& pos = Position(0))
/// Convenience function to allow for a more compact creation of an extraction object
/// with std::deque bulk extraction support.
{
Poco::UInt32 size = static_cast<Poco::UInt32>(t.size());
if (0 == size) throw InvalidArgumentException("Zero length not allowed.");
return new BulkExtraction<std::deque<T> >(t, size, pos);
}
template <typename T>
AbstractExtraction::Ptr into(std::list<T>& t, const Bulk& bulk, const Position& pos = Position(0))
/// Convenience function to allow for a more compact creation of an extraction object
/// with std::list bulk extraction support.
{
return new BulkExtraction<std::list<T> >(t, bulk.size(), pos);
}
template <typename T>
AbstractExtraction::Ptr into(std::list<T>& t, BulkFnType, const Position& pos = Position(0))
/// Convenience function to allow for a more compact creation of an extraction object
/// with std::list bulk extraction support.
{
Poco::UInt32 size = static_cast<Poco::UInt32>(t.size());
if (0 == size) throw InvalidArgumentException("Zero length not allowed.");
return new BulkExtraction<std::list<T> >(t, size, pos);
}
} // namespace Keywords
} } // namespace Poco::Data
#endif // Data_BulkExtraction_INCLUDED