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21 
22 
23 
24 #ifndef SD_SLIDESORTER_ENUMERATION_HXX
25 #define SD_SLIDESORTER_ENUMERATION_HXX
26 
27 #include <memory>
28 
29 namespace sd { namespace slidesorter { namespace model {
30 
31 
32 /** Interface to generic enumerations.  Designed to operate on shared
33     pointers.  Therefore GetNextElement() returns T and not T&.
34 */
35 template <class T>
36 class Enumeration
37 {
38 public:
~Enumeration(void)39     virtual ~Enumeration (void) {}
40 
41     virtual bool HasMoreElements (void) const = 0;
42     /** Returns T instead of T& so that it can handle shared pointers.
43     */
44     virtual T GetNextElement (void) = 0;
45     virtual void Rewind (void) = 0;
46     virtual ::std::auto_ptr<Enumeration<T> > Clone (void) = 0;
47 };
48 
49 } } } // end of namespace ::sd::slidesorter::model
50 
51 #endif
52