如何使这个模板代码工作？

the template code is like this:

模板代码是这样的:

template <class type1>
struct DefaultInstanceCreator {
    type1 * operator ()() {
        return new type1;
    }
};

template < class type1
, class InstanceCreator = DefaultInstanceCreator<type1> >
class objectCache 
{
    public:
        objectCache (InstanceCreator  & instCreator) 
          :instCreator_ (instCreator) {}
        type1* Get() {
            type1 * temp = instCreator_ ();
        }
    private:
        InstanceCreator instCreator_;
};
t