package iterator;

import exceptions.BoundaryViolationException;
import position.Position;
import position.PositionList;

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

/**
 * Created with MONSTER.
 * User: xgiovio
 * Date: 06/04/2014
 * Time: 21:06
 */

//iterator implementation with cursor for PositionList data structures.

public class ElementIterator<E> implements Iterator<E> {

    public ElementIterator (PositionList<E> structure){

        new_structure = structure;

    }

    @Override
    public boolean hasNext() {
        if (pos == null){
            if (new_structure. size() <= 0){
                return false;
            } else {
                return true;
            }

        } else {

            try {
                new_structure.next(pos);
                return true;
            }
            catch (BoundaryViolationException err){
                return false;

            }


        }
    }

    @Override
    public E next() throws NoSuchElementException {
        if (hasNext()){
            if (pos == null){
                pos = new_structure.first();
            }else {
                pos = new_structure.next(pos);
            }
            return pos.element();
        } else{
            throw new NoSuchElementException();
        }
    }

    @Override
    public void remove() {
        throw new UnsupportedOperationException ();
    }

    PositionList<E>  new_structure = null;
    Position<E> pos = null;


}