Why implement a separate iterator class for DoublyLinkedList<T>

[Live4eva_2]

Hi I'm struggling to create a DoublyLinkedList<T> class in Java.
Well,it's actually the iterator that's freaking me out..
Most tutorials and documents I've read use three classes for this:Node<T>,DoublyLinkedList<T> and LinkedListIterator<T>.

I can see the point in creating Node and DoublyLinkedList<T> classes but i don't know why I can't simply just include the 2 iterator reference variables(next and previous) in the DoublyLinkedList<T> class instead of writing an additional iterator class.

 

[Live4eva_2]

OK nevermind that..Let me pose another question:
public class LinkedList<T>
{
public Node<T> first;
public Node<T> last;
protected class Node<T>
{
public Node<T> next;
public Node<T> last;


}
public class Iterator<T>
{
protected Node<T> current;
protected Node<T> previous;


}


}
I've only included the classes and variables in order to illustrate the visibility.
when I complile I'm getting the msg that "Node<T> current" isn't available in LinkedList<T> class...why not !?Am I only allowed one inner class?Also i ensured that my iterator was constructed within the LinkedList constructor so i don't think that it could be a problem with instantiating the iterator object.

 

[Defennder]

Judging by the (non)response you have gotten so far, I think you are better off posting your question here:
https://www.physicsforums.com/forumdisplay.php?f=165