protected int compareBoolean(TableRow other,  int col, boolean b1, boolean b2) {
    // break ties
    if (b1 == b2)
      return compareTie( other, col);
    return b1 ? 1 : -1;
  }
protected int compareBoolean ( TableRow other , int col , boolean b1 , boolean b2 ) { if ( b1 == b2 ) return compareTie ( other , col ) ; return b1 ? 1 : - 1 ; }
for use by the subclass