// @author Frank M. Carrano, Timothy M. Henry
// @version 5.0
public Iterator<VertexInterface<T>> getNeighborIterator()
{
   return new NeighborIterator();
} // end getNeighborIterator

private class NeighborIterator implements Iterator<VertexInterface<T>>
{
   private Iterator<Edge> edges;
   
   private NeighborIterator()
   {
      edges = edgeList.getIterator();
   } // end default constructor
   
   public boolean hasNext()
   {
      return edges.hasNext();
   } // end hasNext
   
   public VertexInterface<T> next()
   {
      VertexInterface<T> nextNeighbor = null;
      
      if (edges.hasNext())
      {
         Edge edgeToNextNeighbor = edges.next();
         nextNeighbor = edgeToNextNeighbor.getEndVertex();
      }
      else
         throw new NoSuchElementException();
      
      return nextNeighbor;
   } // end next
   
   public void remove()
   {
      throw new UnsupportedOperationException();
   } // end remove
} // end NeighborIterator