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// Copyright (C) 2018-2019 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef STAMPED_VALUE_H
#define STAMPED_VALUE_H
#include <cc/data.h>
#include <cc/stamped_element.h>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/mem_fun.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/multi_index_container.hpp>
#include <boost/shared_ptr.hpp>
#include <cstdint>
#include <string>
namespace isc {
namespace data {
class StampedValue;
/// @brief Pointer to the stamped value.
typedef boost::shared_ptr<StampedValue> StampedValuePtr;
/// @brief This class represents a named configuration parameter,
/// e.g. global parameter of the DHCP server.
///
/// Global configuration elements having simple types, e.g. DHCP
/// timers, need to be associatied with modification timestamps.
/// This association is made by deriving from @c StampedElement.
/// The values can be strings, integers, booleans or real numbers.
///
/// Because the strings are more flexible, configuration elements
/// are always held as strings in the configuration backends. This
/// class reflects a single value held in the database. The value
/// can be return in its orginal type or can be returned as a
/// string. Also the null values are allowed.
class StampedValue : public StampedElement {
public:
/// @brief Constructor creating a null value.
///
/// @param name Name of the value.
StampedValue(const std::string& name);
/// @brief Constructor creating a value from the @c Element.
///
/// @param name Name of the value.
/// @param value Value encapsulated in the @c Element object.
///
/// @throw BadValue if the value is null.
/// @throw TypeError if the value is neither a string, integer,
/// bool nor real.
StampedValue(const std::string& name, const ElementPtr& value);
/// @brief Constructor creating a string value.
///
/// Creates stamped value from a string.
///
/// @param name Name of the value.
/// @param value Value to be set.
StampedValue(const std::string& name, const std::string& value);
/// @brief Factory function creating a null value.
///
/// @param name Name of the value.
static StampedValuePtr create(const std::string& name);
/// @brief Factory function creating a value from the @c Element.
///
/// @param name Name of the value.
/// @param value Value encapsulated in the @c Element object.
///
/// @throw BadValue if the value is null.
/// @throw TypeError if the value is neither a string, integer,
/// bool nor real.
static StampedValuePtr create(const std::string& name,
const ElementPtr& value);
/// @brief Factory function creating a string value.
///
/// Creates stamped value from a string.
///
/// @param name Name of the value.
/// @param value Value to be set.
static StampedValuePtr create(const std::string& name,
const std::string& value);
/// @brief Factory function which attempts to convert provided
/// string value to a given type.
///
/// This factory function is useful in cases when the value is
/// read as a string from a database. The string value has to
/// be converted to the appropriate data type. The type is also
/// known from the database.
///
/// @param name Name of the value.
/// @param value Value given as string to be converted.
/// @param type Type of the value to convert to.
static StampedValuePtr create(const std::string& name,
const std::string& value,
Element::types type);
/// @brief Returns a type of the value.
///
/// @return Type of the value as integer. It can be compared
/// with the @c Element::getType() output.
/// @throw InvalidOperation if the value is null.
int getType() const;
/// @brief Returns value name.
///
/// @return Value name.
std::string getName() const {
return (name_);
}
/// @brief Returns value as string.
///
/// It is allowed to call this function for all supported data
/// types. They are converted to a string. For example, a real
/// number of 1.4 will be returned as "1.4". The boolean true
/// value will be returned as "1" etc.
///
/// @return Stored value as string.
/// @throw InvalidOperation if the value is null.
std::string getValue() const;
/// @brief Checks if the value is null.
///
/// @return true if the value is null, false otherwise.
bool amNull() const {
return (!value_);
}
/// @brief Returns value as signed integer.
///
/// @return Stored value as a signed integer.
/// @throw TypeError if the value is not of @c Element::integer
/// type.
int64_t getIntegerValue() const;
/// @brief Returns value as a boolean.
///
/// @return Stored value as a boolean.
/// @throw TypeError if the value is not of @c Element::boolean
/// type.
bool getBoolValue() const;
/// @brief Returns value as a real number.
///
/// @return Stored value as a real number.
/// @throw TypeError if the value is not of @c Element::real
/// type.
double getDoubleValue() const;
/// @brief Returns the value as @c Element.
ConstElementPtr getElementValue() const {
return (value_);
}
private:
/// @brief Checks if the values passed to the constructors
/// were correct.
///
/// This is called from the constructors.
///
/// @throw BadValue if the value is null.
/// @throw TypeError if the value type is neither a string,
/// integer, boolean nor real.
void validateConstruct() const;
/// @brief Checks if the value is accessed correctly.
///
/// This is called from the accessors of this class.
///
/// @param type Type of the value expected by the accessor
/// function.
///
/// @throw InvalidOperation if the accessed value is null.
/// @throw TypeError if the expected type is not a string
/// and it doesn't match the value type.
void validateAccess(Element::types type) const;
/// @brief Name of the value.
std::string name_;
/// @brief Stored value.
ElementPtr value_;
};
/// @name Definition of the multi index container for @c StampedValue.
///
//@{
/// @brief Tag for the index for access by value name.
struct StampedValueNameIndexTag { };
/// @brief Tag for the index for access by modification time.
struct StampedValueModificationTimeIndexTag { };
/// @brief Multi index container for @c StampedValue.
typedef boost::multi_index_container<
StampedValuePtr,
boost::multi_index::indexed_by<
// Index used to access value by name.
boost::multi_index::hashed_non_unique<
boost::multi_index::tag<StampedValueNameIndexTag>,
boost::multi_index::const_mem_fun<
StampedValue,
std::string,
&StampedValue::getName
>
>,
// Index used to access value by modification time.
boost::multi_index::ordered_non_unique<
boost::multi_index::tag<StampedValueModificationTimeIndexTag>,
boost::multi_index::const_mem_fun<
BaseStampedElement,
boost::posix_time::ptime,
&BaseStampedElement::getModificationTime
>
>
>
> StampedValueCollection;
//@}
} // end of namespace isc::data
} // end of namespace isc
#endif
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