no.bekk.bekkopen.date.NorwegianDateUtil Maven / Gradle / Ivy
package no.bekk.bekkopen.date;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.TimeZone;
/**
* Utility class for Norwegian dates.
*/
public class NorwegianDateUtil {
private static Map> holidays;
/**
* Adds the given number of working days to the given date. A working day is
* specified as a regular Norwegian working day, excluding weekends and all
* national holidays.
*
* Example 1:
* - Add 5 working days to Wednesday 21.03.2007 -> Yields Wednesday
* 28.03.2007. (skipping saturday and sunday)
*
* Example 2:
* - Add 5 working days to Wednesday 04.04.2007 (day before
* easter-long-weekend) -> yields Monday 16.04.2007 (skipping 2 weekends and
* 3 weekday holidays).
*
* @param date
* The original date.
* @param days
* The number of working days to add.
* @return The new date.
*/
public static Date addWorkingDaysToDate(Date date, int days) {
Calendar cal = dateToCalendar(date);
for (int i = 0; i < days; i++) {
cal.add(Calendar.DATE, 1);
while (!isWorkingDay(cal)) {
cal.add(Calendar.DATE, 1);
}
}
return cal.getTime();
}
/**
* Will check if the given date is a working day. That is check if the given
* date is a weekend day or a national holiday.
*
* @param date
* The date to check.
* @return true if the given date is a working day, false otherwise.
*/
public static boolean isWorkingDay(Date date) {
return isWorkingDay(dateToCalendar(date));
}
/**
* Check if given Date object is a holiday.
*
* @param date
* The Date to check.
* @return true if holiday, false otherwise.
*/
public static boolean isHoliday(Date date) {
return isHoliday(dateToCalendar(date));
}
/**
* Return a sorted array of holidays for a given year.
*
* @param year
* The year to get holidays for.
* @return The array of holidays, sorted by date.
*/
public static Date[] getHolidays(int year) {
Set days = getHolidaySet(year);
Date[] dates = days.toArray(new Date[days.size()]);
Arrays.sort(dates);
return dates;
}
/**
* Get a set of holidays for a given year.
*
* @param year
* The year to get holidays for.
* @return The set of dates.
*/
private static Set getHolidaySet(int year) {
if (holidays == null) {
holidays = new HashMap>();
}
if (!holidays.containsKey(year)) {
Set yearSet = new HashSet();
// Add set holidays.
yearSet.add(getDate(1, Calendar.JANUARY, year));
yearSet.add(getDate(1, Calendar.MAY, year));
yearSet.add(getDate(17, Calendar.MAY, year));
yearSet.add(getDate(25, Calendar.DECEMBER, year));
yearSet.add(getDate(26, Calendar.DECEMBER, year));
// Add movable holidays - based on easter day.
Calendar easterDay = dateToCalendar(getEasterDay(year));
// Sunday before easter.
yearSet.add(rollGetDate(easterDay, -7));
// Thurday before easter.
yearSet.add(rollGetDate(easterDay, -3));
// Friday before easter.
yearSet.add(rollGetDate(easterDay, -2));
// Easter day.
yearSet.add(easterDay.getTime());
// Second easter day.
yearSet.add(rollGetDate(easterDay, 1));
// "Kristi himmelfart" day.
yearSet.add(rollGetDate(easterDay, 39));
// "Pinse" day.
yearSet.add(rollGetDate(easterDay, 49));
// Second "Pinse" day.
yearSet.add(rollGetDate(easterDay, 50));
holidays.put(year, yearSet);
}
return holidays.get(year);
}
/**
* Will check if the given date is a working day. That is check if the given
* date is a weekend day or a national holiday.
*
* @param cal
* The Calendar object representing the date.
* @return true if the given date is a working day, false otherwise.
*/
private static boolean isWorkingDay(Calendar cal) {
return cal.get(Calendar.DAY_OF_WEEK) != Calendar.SATURDAY && cal.get(Calendar.DAY_OF_WEEK) != Calendar.SUNDAY
&& !isHoliday(cal);
}
/**
* Check if given Calendar object represents a holiday.
*
* @param cal
* The Calendar to check.
* @return true if holiday, false otherwise.
*/
private static boolean isHoliday(Calendar cal) {
int year = cal.get(Calendar.YEAR);
Set yearSet = getHolidaySet(year);
for (Object aYearSet : yearSet) {
Date date = (Date) aYearSet;
if (checkDate(cal, dateToCalendar(date))) {
return true;
}
}
return false;
}
/**
* Calculates easter day (sunday) by using Spencer Jones formula found here:
* Wikipedia -
* Påskeformelen
*
* @param year
* The year to calculate from.
* @return The Calendar object representing easter day for the given year.
*/
private static Date getEasterDay(int year) {
int a = year % 19;
int b = year / 100;
int c = year % 100;
int d = b / 4;
int e = b % 4;
int f = (b + 8) / 25;
int g = (b - f + 1) / 3;
int h = ((19 * a) + b - d - g + 15) % 30;
int i = c / 4;
int k = c % 4;
int l = (32 + (2 * e) + (2 * i) - h - k) % 7;
int m = (a + (11 * h) + (22 * l)) / 451;
int n = (h + l - (7 * m) + 114) / 31; // This is the month number.
int p = (h + l - (7 * m) + 114) % 31; // This is the date minus one.
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, n - 1);
cal.set(Calendar.DATE, p + 1);
return cal.getTime();
}
/**
* Check if the given dates match on day and month.
*
* @param cal
* The Calendar representing the first date.
* @param other
* The Calendar representing the second date.
* @return true if they match, false otherwise.
*/
private static boolean checkDate(Calendar cal, Calendar other) {
return checkDate(cal, other.get(Calendar.DATE), other.get(Calendar.MONTH));
}
/**
* Check if the given date represents the given date and month.
*
* @param cal
* The Calendar object representing date to check.
* @param date
* The date.
* @param month
* The month.
* @return true if they match, false otherwise.
*/
private static boolean checkDate(Calendar cal, int date, int month) {
return cal.get(Calendar.DATE) == date && cal.get(Calendar.MONTH) == month;
}
/**
* Convert the given Date object to a Calendar instance.
*
* @param date
* The Date object.
* @return The Calendar instance.
*/
private static Calendar dateToCalendar(Date date) {
Calendar cal = Calendar.getInstance();
cal.setTime(date);
return cal;
}
/**
* Add the given number of days to the calendar and convert to Date.
*
* @param calendar
* The calendar to add to.
* @param days
* The number of days to add.
* @return The date object given by the modified calendar.
*/
private static Date rollGetDate(Calendar calendar, int days) {
Calendar easterSunday = (Calendar) calendar.clone();
easterSunday.add(Calendar.DATE, days);
return easterSunday.getTime();
}
/**
* Get the date for the given values.
*
* @param day
* The day.
* @param month
* The month.
* @param year
* The year.
* @return The date represented by the given values.
*/
private static Date getDate(int day, int month, int year) {
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, month);
cal.set(Calendar.DATE, day);
return cal.getTime();
}
}
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