code: public GeometryIndex getParent(GeometryIndex index) {
  		GeometryIndex parent = new GeometryIndex(index);
  		GeometryIndex deepestParent = null;
  		GeometryIndex p = parent;
  		while (p.hasChild()) {
  			deepestParent = p;
  			p = p.getChild();
  		}
  		if (deepestParent != null) {
  			deepestParent.setChild(null);
  		}
  		return parent;
  	}
docs: Returns a new index that is one level higher than this index. Useful to get the index of a ring for a vertex.
  
  @param index
  @return the parent index