///\param theWithEmpty if it is false, counts the not-empty referenced objects only
virtual ObjectPtr object(const int theIndex, const bool theWithEmpty = true) const = 0;
- /// Substitutes the feature by another one. Does nothing if such object is not found.
+ /// Substitutes the object by another one. Does nothing if such object is not found.
virtual void substitute(const ObjectPtr& theCurrent, const ObjectPtr& theNew) = 0;
+ /// Substitutes the object by another one and back. So, features wil become exchanged in the list
+ virtual void exchange(const ObjectPtr& theObject1, const ObjectPtr& theObject2) = 0;
+
/// Removes the last element in the list.
virtual void removeLast() = 0;