86 lines
2.1 KiB
C++
86 lines
2.1 KiB
C++
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#ifndef FACTORY_HPP_QLKNHPWZ
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#define FACTORY_HPP_QLKNHPWZ
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#include <functional>
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#include <map>
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#include <memory>
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#include <utility>
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namespace vanetza
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{
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/**
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* Factory for a group of classes implementing T
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*/
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template<typename T, typename... Args>
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class Factory
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{
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public:
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using Result = std::unique_ptr<T>;
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using Function = std::function<Result(Args...)>;
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Factory() : m_default(m_functions.end())
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{
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}
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/**
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* Create an instance of T using a named implementation
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* \param name of wanted implementation
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* \return created instance or nullptr if not found
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*/
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Result create(const std::string& name, Args... args) const
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{
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std::unique_ptr<T> obj;
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auto found = m_functions.find(name);
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if (found != m_functions.end()) {
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obj = found->second(std::forward<Args>(args)...);
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}
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return obj;
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}
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/**
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* Create object using default implementation
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* \return created instance or nullptr if no default is configured
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*/
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Result create(Args... args) const
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{
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std::unique_ptr<T> obj;
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if (m_default != m_functions.end()) {
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obj = m_default->second(std::forward<Args>(args)...);
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}
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return obj;
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}
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/**
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* Add an implementation to factory
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* \param name of implementation
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* \param f function creating a new instance of this implementation
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* \return true if added successfully, i.e. no previous addition with same name
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*/
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bool add(const std::string& name, Function f)
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{
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return m_functions.emplace(name, std::move(f)).second;
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}
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/**
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* Set default implementation
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* \param name selected default implementation
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* \return true if an implementation exists with selected name
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*/
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bool configure_default(const std::string& name)
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{
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m_default = m_functions.find(name);
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return m_default != m_functions.end();
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}
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private:
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using map_type = std::map<std::string, Function>;
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map_type m_functions;
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typename map_type::const_iterator m_default;
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};
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} // namespace vanetza
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#endif /* FACTORY_HPP_QLKNHPWZ */
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