package iterator;

import position.Position;
import position.PositionList;

import java.util.Iterator;
import java.util.NoSuchElementException;


public class ElementIterator<E> implements Iterator<E> {
  protected PositionList<E> list; // the underlying list
  protected Position<E> cursor; // the next position

  public ElementIterator(PositionList<E> L) {
    list = L;
    cursor = (list.isEmpty())? null : list.first();
  }

  public boolean hasNext() { return (cursor != null);  }

  public E next() throws NoSuchElementException {
    if (cursor == null)
      throw new NoSuchElementException("No next element");
    E toReturn = cursor.element();
    cursor = (cursor == list.last())? null : list.next(cursor);
    return toReturn;
  }

  public void remove() throws UnsupportedOperationException {
    throw new UnsupportedOperationException("remove");
  }

}