code: public Node item(int i)
    {
  
      int count = 0;
  
      for (int n = dtm.getFirstAttribute(element); n != -1;
              n = dtm.getNextAttribute(n))
      {
        if (count == i)
          return dtm.getNode(n);
        else
          ++count;
      }
  
      return null;
    }
docs: Returns the <code>index</code>th item in the map. If <code>index</code>
  is greater than or equal to the number of nodes in this map, this
  returns <code>null</code>.
  @param i The index of the requested item.
  @return The node at the <code>index</code>th position in the map, or
  <code>null</code> if that is not a valid index.