An iterator definitely needs to know about the collection that it needs to iterate. Should I also collect information about its iterator? Is addiction one or two ways? If a collection has knowledge of a particular iterator implementation, then it may not be possible to have different iterator strategies for the same collection. That is my thought. Am I right, or did I understand that this is completely wrong?
The GoF book has this diagram for the Iterator template:
I think this implies circular dependence. I am not sure about the dashed lines from Listbefore LisIteratorand SkipListto SkipListIterator.
PS: I do Java every day, but maybe this is more a design issue than a specific language.