public static Map ordinalMap(Iterator tuples,String field,Comparator cmp){
  Object[] o=ordinalArray(tuples,field,cmp);
  HashMap map=new HashMap();
  for (int i=0; i < o.length; ++i)   map.put(o[i],new Integer(i));
  return map;
}

public static Map ordinalMap ( Iterator tuples , String field , Comparator cmp ) { Object [ ] o = ordinalArray ( tuples , field , cmp ) ; HashMap map = new HashMap ( ) ; for ( int i = 0 ; i < o . length ; ++ i ) map . put ( o [ i ] , new Integer ( i ) ) ; return map ; }
get map mapping from column values ( as object instances ) to their ordinal index in a sorted array .
