public OrderByClause add(String property,boolean isDescending){
  orderByExpressions.add(new OrderByElement(Expressions.getPropExpr(property),isDescending));
  return this;
}

public OrderByClause add ( String property , boolean isDescending ) { orderByExpressions . add ( new OrderByElement ( Expressions . getPropExpr ( property ) , isDescending ) ) ; return this ; }
adds a property and flag .
