從STL容器繼承實現而不是委托可以嗎？我有一個類來適應std：vectory來建模特定于域的對象的容器。我希望向用戶公開大部分STD：VectorAPI，以便他/她可以使用熟悉的方法(大小、清除、at等)。以及容器上的標準算法。在我的設計中，這似乎是一種反復出現的模式：class MyContainer : public std::vector<MyObject>{public:
// Redeclare all container traits: value_type, iterator, etc...
// Domain-specific constructors
// (more useful to the user than std::vector ones...)
// Add a few domain-specific helper methods...
// Perhaps modify or hide a few methods (domain-related)};我知道在為實現重用類時更喜歡組合而不是繼承的做法-但是一定會有限制的！如果我將所有內容委托給std：vectoral，那么就會有32個轉發函數！所以我的問題是.。在這種情況下繼承實現真的那么糟糕嗎？風險有多大？有沒有更安全的方法，我可以實現這一點，而不需要這么多的打字？我是一個使用實現繼承的異端者嗎？：)編輯：如何明確說明用戶不應通過std：Vectoral<>指針使用MyContainer：// non_api_header_file.hnamespace detail{
typedef std::vector<MyObject> MyObjectBase;}// api_header_file.hclass MyContainer : public detail::MyObjectBase{
// ...};Boost庫似乎一直在做這件事。編輯2：其中一項建議是使用免費功能。我將在這里顯示為偽代碼：typedef std::vector<MyObject> MyCollection;void specialCollectionInitializer(MyCollection& c, arguments...);result specialCollectionFunction(const MyCollection& c);etc...一種更OO的方法：typedef std::vector<MyObject> MyCollection;class MyCollectionWrapper{public:
// Constructor
MyCollectionWrapper(arguments...) {construct coll_}
// Access collection directly
MyCollection& collection() {return coll_;}
const MyCollection& collection() const {return coll_;}
// Special domain-related methods
result mySpecialMethod(arguments...);private:
MyCollection coll_;
// Other domain-specific member variables used
// in conjunction with the c
3 回答
慕斯王
TA貢獻1864條經驗 獲得超2個贊
template <typename Container>class readonly_container_facade {public:
typedef typename Container::size_type size_type;
typedef typename Container::const_iterator const_iterator;
virtual ~readonly_container_facade() {}
inline bool empty() const { return container.empty(); }
inline const_iterator begin() const { return container.begin(); }
inline const_iterator end() const { return container.end(); }
inline size_type size() const { return container.size(); }protected: // hide to force inherited usage only
readonly_container_facade() {}protected: // hide assignment by default
readonly_container_facade(readonly_container_facade const& other):
: container(other.container) {}
readonly_container_facade& operator=(readonly_container_facade& other) {
container = other.container;
return *this;
}protected:
Container container;};template <typename Container>class writable_container_facade: public readable_container_facade<Container> {public:
typedef typename Container::iterator iterator;
writable_container_facade(writable_container_facade& other)
readonly_container_facade(other) {}
virtual ~writable_container_facade() {}
inline iterator begin() { return container.begin(); }
inline iterator end() { return container.end(); }
writable_container_facade& operator=(writable_container_facade& other) {
readable_container_facade<Container>::operator=(other);
return *this;
}};- 3 回答
- 0 關注
- 616 瀏覽
添加回答
舉報
0/150
提交
取消