+ ///\param theIndex zero-based index in the list
+ ///\param theWithEmpty if it is false, counts the not-empty referenced objects only
+ MODEL_EXPORT virtual ObjectPtr object(const int theIndex, const bool theWithEmpty = true);
+
+ /// Substitutes the feature by another one. Does nothing if such object is not found.
+ /// Does not support the external documents objects yet.
+ MODEL_EXPORT virtual void substitute(const ObjectPtr& theCurrent, const ObjectPtr& theNew);
+
+ /// Removes the last element in the list.
+ /// Does not support the external documents objects yet.
+ MODEL_EXPORT virtual void removeLast();
+
+ /// Removes the elements from the list.
+ /// Does not support the external documents objects yet.
+ /// \param theIndices a list of indices of elements to be removed
+ MODEL_EXPORT virtual void remove(const std::set<int>& theIndices);
+
+ /// Returns true if attribute was initialized by some value
+ MODEL_EXPORT virtual bool isInitialized();
+
+ /// Erases the hashed objects caused by complicated modifications in the list
+ void eraseHash();