private int calculateSize( PerfectHashMap<TrieNode<S, T>> nodes )
   {
      int size = 0;

      if (nodes != null)
      {
         for (int i = nodes.capacity() - 1; i >= 0; i--)
         {
            TrieNode<S, T> n = nodes.valueAt( i );

            if (n != null)
            {
               size += n.size;
            }
         }
      }

      return size;
   }