struct Category {
    long id;
    string name;
};
struct Product {
    long id;
    long version;
    string name;
    long stock;
    Category category;
};

struct OrderItem {
    Product product;
    long amount;
};

interface shoppingBasket {
    typedef sequence<OrderItem> orderItemsList;
    orderItemsList getOrderItemsList();
    void AddProduct(in long productId, in long amount);
    void PlaceAnOrder();
};

interface shoppingBasketProvider {
    typedef sequence<shoppingBasket> shoppingBaskets;
    shoppingBasket createNewShoppingBasket();
    void deleteShoppingBasket(in shoppingBasket shoppingBasket);
};