+template<typename T>
+class DirectoryCollection::ItemLoader<T, false>: public T::Loader
+{
+public:
+ ItemLoader(T &o, Collection &):
+ T::Loader(o)
+ { }
+};
+
+template<typename T>
+class DirectoryCollection::ItemLoader<T, true>: public T::Loader
+{
+public:
+ ItemLoader(T &o, Collection &c):
+ T::Loader(o, dynamic_cast<typename T::Loader::Collection &>(c))
+ { }
+};
+