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/****************************************************************************
* Copyright (C) 2009-2015 EPAM Systems
*
* This file is part of Indigo toolkit.
*
* This file may be distributed and/or modified under the terms of the
* GNU General Public License version 3 as published by the Free Software
* Foundation and appearing in the file LICENSE.GPL included in the
* packaging of this file.
*
* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
***************************************************************************/
#ifndef __nullable__
#define __nullable__
#include "base_cpp/exception.h"
namespace indigo
{
DECL_EXCEPTION(NullableError);
template <typename T>
class Nullable
{
public:
Nullable () : _has_value(false), variable_name("<Undefined>") {}
const T& get () const
{
if (!_has_value)
throw Error("%s variable was not set");
return _value;
}
operator const T& () const
{
return get();
}
Nullable<T>& operator= (const T& value)
{
set(value);
return *this;
}
void set (const T& value)
{
_value = value;
_has_value = true;
}
void reset ()
{
_has_value = false;
}
bool hasValue () const
{
return _has_value;
}
void setName (const char *name)
{
variable_name = name;
}
DECL_TPL_ERROR(NullableError);
private:
T _value;
bool _has_value;
const char *variable_name;
};
}
#endif // __nullable__
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