C++11 example for my post - An introduction to C++'s variadic templates: a thread-safe multi-type map - using shared_ptr

repository_shared_ptr.cpp

#include <iostream>
#include <string>

struct DefaultSlotKey;

template <class Type, class Key = DefaultSlotKey>
class Slot
{
public:
    std::shared_ptr<Type> doGet() const
    {
        return value_;
    }

    void doSet(const std::shared_ptr<Type> &value)
    {
        value_ = value;
    }

private:
    std::shared_ptr<Type> value_;
};

template<class... Slots>
class Repository : private Slots... {
public:
    template <class Type, class Key = DefaultSlotKey>
    std::shared_ptr<Type> get()
    {
        static_assert(std::is_base_of<Slot<Type, Key>, Repository<Slots...>>::value,
                      "Please ensure that this type or this key exists in this repository");
        return Slot<Type, Key>::doGet();
    }

    template <class Type, class Key = DefaultSlotKey>
    void set(const std::shared_ptr<Type>& value)
    {
        static_assert(std::is_base_of<Slot<Type, Key>, Repository<Slots...>>::value,
                      "Please ensure that this type or this key exists in this repository");
        Slot<Type, Key>::doSet(value);
    }

    template <class Type, class Key = DefaultSlotKey, class ...Args>
    void emplace(Args&&... args)
    {
        static_assert(std::is_base_of<Slot<Type, Key>, Repository<Slots...>>::value,
                      "Please ensure that this type or this key exists in this repository");
        Slot<Type, Key>::doSet(std::make_shared<Type>(std::forward<Args>(args)...));
    }

    template <class Type, class Key = DefaultSlotKey>
    auto getWatcher() -> decltype(std::declval<Slot<Type, Key>>().doGetWatcher())
    {
        return Slot<Type, Key>::doGetWatcher();
    }
};

// Incomplete types used as compile-time keys.
struct Key1;
struct Key2;

// Create a type for our repository.
using MyRepository = Repository
        <
                Slot<int>,       // Let's pick the type of our slots.
                Slot<std::string>
        >;

int main()
{
    MyRepository myRepository;
    myRepository.emplace<std::string>("toto");

    std::cout << *myRepository.get<std::string>();


    return EXIT_SUCCESS;
}