import java.util.Iterator;

/**
 * An Iterator that supports traversing a SimpleLinkedList.
 * Normally, this would be integrated into the SimpleLinkedList
 * class by adding the iterator() method to the SimpleLinkedList class:
 *
 *  @Override
 *  public Iterator<T> iterator() {
 *    return new SimpleLinkedListIterator(this);
 *  }
 *
 *  Note: this iterator class must be an inner class
 *  within SimpleLinkedList, since it makes use of the private
 *  Node inner class within SimpleLinkedList.
 *
 */
public static class SimpleLinkedListIterator<T> implements Iterator<T> {

  // next node in the traversal
  private Node<T> nextNode;

  public SimpleLinkedListIterator(SimpleLinkedList<T> list) {
    nextNode = list.head;
  }

  @Override
  public boolean hasNext() {
    return nextNode != null;
  }

  @Override
  public T next() {
    T val = nextNode.data;
    nextNode = nextNode.next;
    return val;
  }

}