Utils class to calculate and work with holidays in a country (here in Luxembourg)

DateUtils.scala

package utils

import org.joda.time.{Period, LocalDate}

object DateUtils {
  def dateRange(from: LocalDate, to: LocalDate, step: Period): Iterator[LocalDate] =
    Iterator.iterate(from) {
      dt => dt.plus(step)
    }.takeWhile(!_.isAfter(to))

  def workDayRange(year: Int)(from: LocalDate, to: LocalDate): Iterator[LocalDate] =
    Iterator.iterate(from) {
      nextWorkDay(year)(_)
    }.takeWhile(!_.isAfter(to))

  def nextWorkDay(year: Int)(date: LocalDate): LocalDate = {
    val next = date.plusDays(1)
    if (isWorkDay(year)(next))
      next
    else
      nextWorkDay(year)(next)
  }

  def isWorkDay(year: Int)(date: LocalDate): Boolean = {
    date.getDayOfWeek != 6 &&
    date.getDayOfWeek != 7 &&
    !holidays(year).contains(date)
  }

  def fixedHolidays(year: Int) = Set(
    new LocalDate(year, 12, 25),
    new LocalDate(year, 12, 26),
    new LocalDate(year, 1, 1),
    new LocalDate(year, 6, 23),
    new LocalDate(year, 8, 15),
    new LocalDate(year, 5, 1),
    new LocalDate(year, 11, 1))

  def mobileHolidays(year: Int) = {
    val easterSunday = easter(year)
    val easterMonday = easterSunday.plusDays(1)
    val ascension = easterSunday.plusDays(39)
    val pentecote = easterSunday.plusDays(50)
    Set(easterMonday, ascension, pentecote)
  }

  def holidays(year: Int) = fixedHolidays(year) ++ mobileHolidays(year)

  def sortedHolidays(year: Int) = holidays(year).toList.sortWith((d1,d2) => d1.isBefore(d2))

  def easter(year: Int) = {
    val g = year % 19
    val c = Math.floor(year / 100)
    val c_4 = Math.floor(c / 4)
    val h = (19 * g + c - c_4 - Math.floor((8 * c + 13) / 25) + 15) % 30
    val k = Math.floor(h / 28)
    val i = (k * Math.floor(29 / (h + 1)) * Math.floor((21 - g) / 11) - 1) * k + h
    val weekDay = (Math.floor(year / 4) + year + i + 2 + c_4 - c) % 7
    val presDay = (28 + i - weekDay).toInt
    val month = if (presDay > 31) 3 else 2
    val dayInMonth = if (month == 2) presDay else presDay - 31
    new LocalDate(year, month + 1, dayInMonth)
  }

}

Great, thanks for sharing!

We'll modify your code and post a solution for the German holidays.