Question

我知道我可以通过使用Guava中的Preconditions类或通过提取方法isValidDayOfWeek()来即兴发挥这一点（消除显式抛出）。但这不是我想要的。有没有办法在不使用switch语句的情况下简化此逻辑？此检查确保startDayOfWeek是本周7个值中的一个。

public static TimeSlice getPreviousWeek(Date referenceDate, int startDayOfWeek)
{
  if (!((startDayOfWeek == Calendar.SUNDAY) || (startDayOfWeek == Calendar.MONDAY) || (startDayOfWeek == Calendar.TUESDAY)
                || (startDayOfWeek == Calendar.WEDNESDAY) || (startDayOfWeek == Calendar.THURSDAY)
                || (startDayOfWeek == Calendar.FRIDAY) || (startDayOfWeek == Calendar.SATURDAY)))
  {
            throw new IllegalArgumentException("getPreviousWeek(): invalid startDayOfWeek:" + startDayOfWeek);
  }
}

Answer 1

保证一周中某些天的值documented，SUNDAY == 1和SATURDAY == 7所以你只想要：

if (startDayOfWeek < Calendar.SUNDAY || startDayOfWeek > Calendar.SATURDAY)
{
    throw ...;
}

如果你想让它清晰透明，你可以随时使用：

private static final Set<Integer> VALID_DAYS = ImmutableSet.of(
    Calendar.SUNDAY, Calendar.MONDAY, Calendar.TUESDAY,
    Calendar.WEDNESDAY, Calendar.THURSDAY, Calendar.FRIDAY,
    Calendar.SATURDAY);

public static TimeSlice getPreviousWeek(Date referenceDate, int startDayOfWeek)
{
    if (!VALID_DAYS.contains(startDayOfWeek))
    {
        throw ...
    }
}

（那是使用Guava的ImmutableSet，但如果你愿意，可以使用别的东西。）

Answer 2

你可以这样做：

if ((startDayOfWeek < Calendar.SUNDAY) || (startDayOfWeek > Calendar.SATURDAY))

在前置条件检查中简化if逻辑

2 个答案: