Difference between two dates, including only business days (i.e. excluding weekends and holidays)
How can I get the number of business days between two java.util.Date, i.e. excluding weekends and holidays? By holidays, I mean legally recognized holidays. It must be depending on the country, because of the holidays that are different from a country to another.
For example, 2012-08-27 - 2012-08-24 should return 1 instead of 3, because of the weekend inbetween.
I already had a look on Jollyday and ObjectLab-Kit, but I can't make them meet my need. I mean, both of them have a lot of interesting methods, but can't find something like getBusinessDaysCount(Date d1, Date d2)...
Answer
Here is finally a solution based on the Calendar API:
/**
* Handles holidays by country.
*/
public enum Holidays {
/**
* See <a href="http://www.wikiwand.com/en/Public_holidays_in_France">http://www.wikiwand.com/en/Public_holidays_in_France</a>.
*/
FRANCE {
@Override
protected void addFixedHolidays(Set<Holiday> holidays) {
holidays.add(new Holiday(Calendar.JANUARY, 1));
holidays.add(new Holiday(Calendar.MAY, 1));
holidays.add(new Holiday(Calendar.MAY, 8));
holidays.add(new Holiday(Calendar.JULY, 14));
holidays.add(new Holiday(Calendar.AUGUST, 15));
holidays.add(new Holiday(Calendar.NOVEMBER, 1));
holidays.add(new Holiday(Calendar.NOVEMBER, 11));
holidays.add(new Holiday(Calendar.DECEMBER, 25));
}
@Override
protected void addVariableHolidays(int year, Set<Holiday> holidays) {
Date easterSunday = getEasterSunday(year);
holidays.add(new Holiday(getEasterMonday(easterSunday)));
holidays.add(new Holiday(getAscensionThursday(easterSunday)));
holidays.add(new Holiday(getPentecostMonday(easterSunday)));
}
},
/**
* See <a href="http://www.wikiwand.com/en/Public_holidays_in_the_United_Kingdom">http://www.wikiwand.com/en/Public_holidays_in_the_United_Kingdom</a>.
*/
ENGLAND {
@Override
protected void addFixedHolidays(Set<Holiday> holidays) {
holidays.add(new Holiday(Calendar.JANUARY, 1));
holidays.add(new Holiday(Calendar.DECEMBER, 25));
holidays.add(new Holiday(Calendar.DECEMBER, 26));
}
@Override
protected void addVariableHolidays(int year, Set<Holiday> holidays) {
Date easterSunday = getEasterSunday(year);
holidays.add(new Holiday(getGoodFriday(easterSunday)));
holidays.add(new Holiday(getEasterMonday(easterSunday)));
holidays.add(new Holiday(get(WeekdayIndex.FIRST, Calendar.MONDAY, Calendar.MAY, year)));
holidays.add(new Holiday(get(WeekdayIndex.LAST, Calendar.MONDAY, Calendar.MAY, year)));
holidays.add(new Holiday(get(WeekdayIndex.LAST, Calendar.MONDAY, Calendar.AUGUST, year)));
Holiday christmasDay = new Holiday(Calendar.DECEMBER, 25);
if (christmasDay.isWeekend(year)) {
holidays.add(new Holiday(Calendar.DECEMBER, 27));
}
Holiday boxingDay = new Holiday(Calendar.DECEMBER, 26);
if (boxingDay.isWeekend(year)) {
holidays.add(new Holiday(Calendar.DECEMBER, 28));
}
}
};
public class HolidayException extends Exception {
private static final long serialVersionUID = 1L;
private HolidayException(String message) {
super(message);
}
}
/**
* A holiday is defined by a {@link Calendar#MONTH} and a {@link Calendar#DAY_OF_MONTH}.
*/
private class Holiday {
private final int day;
private final int month;
public Holiday(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
month = calendar.get(Calendar.MONTH);
day = calendar.get(Calendar.DAY_OF_MONTH);
}
public Holiday(int month, int day) {
this.month = month;
this.day = day;
}
public Date toDate(int year) {
Calendar calendar = Calendar.getInstance();
calendar.set(year, month, day);
return calendar.getTime();
}
public boolean isWeekend(int year) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(toDate(year));
int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
return dayOfWeek == Calendar.SATURDAY || dayOfWeek == Calendar.SUNDAY;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
} else if (!(obj instanceof Holiday)) {
return false;
} else {
Holiday holiday = (Holiday) obj;
return holiday.month == month && holiday.day == day;
}
}
@Override
public int hashCode() {
return Arrays.hashCode(new int[] { month, day });
}
}
/**
* Use with {@link Holidays#get(WeekdayIndex, int, int, int)}.<br />
* <br />
* Example: <code>Holidays.get(WeekdayIndex.FIRST, Calendar.MONDAY, Calendar.MAY, 2000)</code>.
*/
public enum WeekdayIndex {
FIRST(1), SECOND(2), THIRD(3), FOURTH(4), LAST(null);
private final Integer index;
private WeekdayIndex(Integer index) {
this.index = index;
}
private boolean is(int count) {
return index != null && index == count;
}
}
private final Set<Holiday> fixedHolidays = new HashSet<Holiday>();
private final Map<Integer, Set<Holiday>> variableHolidays = new HashMap<Integer, Set<Holiday>>();
private Holidays() {
addFixedHolidays(fixedHolidays);
}
protected abstract void addFixedHolidays(Set<Holiday> holidays);
protected abstract void addVariableHolidays(int year, Set<Holiday> holidays);
/**
* Returns the number of business days between two dates.
*
* @param d1
* The first date.
* @param d2
* The second date.
* @return The number of business days between the two provided dates.
* @throws HolidayException
* If <code>d1</code> or <code>d2</code> is not a business day.
*/
public int getBusinessDayCount(Date d1, Date d2) throws HolidayException {
Calendar calendar = Calendar.getInstance();
DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
try {
d1 = formatter.parse(formatter.format(d1));
d2 = formatter.parse(formatter.format(d2));
} catch (ParseException ignore) {
// cannot happen
}
if (!isBusinessDay(d1) || !isBusinessDay(d2)) {
throw new HolidayException("Input dates must be business days");
}
int businessDayCount = 0;
Date min = d1.before(d2) ? d1 : d2;
Date max = min.equals(d2) ? d1 : d2;
calendar.setTime(min);
while (calendar.getTime().before(max)) {
calendar.add(Calendar.DAY_OF_MONTH, 1);
if (isBusinessDay(calendar.getTime())) {
businessDayCount++;
}
}
return businessDayCount;
}
/**
* Returns whether a date is a business day.
*
* @param date
* The date.
* @return <code>true</code> if the <code>date</code> is a business day, <code>false</code> otherwise.
*/
public boolean isBusinessDay(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
if (dayOfWeek == Calendar.SATURDAY || dayOfWeek == Calendar.SUNDAY) {
return false;
} else if (isFixedHoliday(date)) {
return false;
} else if (isVariableHoliday(date)) {
return false;
}
return true;
}
private boolean isFixedHoliday(Date date) {
return fixedHolidays.contains(new Holiday(date));
}
private boolean isVariableHoliday(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
int year = calendar.get(Calendar.YEAR);
Set<Holiday> yearHolidays;
if (!variableHolidays.containsKey(year)) {
// variable holidays have not been calculated for this year yet
yearHolidays = new HashSet<Holiday>();
addVariableHolidays(year, yearHolidays);
variableHolidays.put(year, yearHolidays);
} else {
yearHolidays = variableHolidays.get(year);
}
return yearHolidays.contains(new Holiday(date));
}
public static Date getEasterSunday(int year) {
// credits: https://www.wikiwand.com/en/Computus#/Anonymous_Gregorian_algorithm
Calendar calendar = Calendar.getInstance();
int initialYear = year;
if (year < 1900) {
year += 1900;
}
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 j = c % 4;
int k = (32 + 2 * e + 2 * i - h - j) % 7;
int l = (a + 11 * h + 22 * k) / 451;
int m = (h + k - 7 * l + 114) % 31;
int month = (h + k - 7 * l + 114) / 31 - 1;
int day = m + 1;
calendar.set(initialYear, month, day);
return calendar.getTime();
}
public static Date getGoodFriday(Date easterSunday) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(easterSunday);
calendar.add(Calendar.DAY_OF_MONTH, -2);
return calendar.getTime();
}
public static Date getEasterMonday(Date easterSunday) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(easterSunday);
calendar.add(Calendar.DAY_OF_MONTH, 1);
return calendar.getTime();
}
public static Date getAscensionThursday(Date easterSunday) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(easterSunday);
calendar.add(Calendar.DAY_OF_MONTH, 39);
return calendar.getTime();
}
public static Date getPentecostMonday(Date easterSunday) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(easterSunday);
calendar.add(Calendar.DAY_OF_MONTH, 50);
return calendar.getTime();
}
public static Date get(WeekdayIndex weekdayIndex, int dayOfWeek, int month, int year) {
Calendar calendar = Calendar.getInstance();
calendar.set(year, month, 1);
int count = 0;
Date last = null;
do {
if (calendar.get(Calendar.DAY_OF_WEEK) == dayOfWeek) {
count++;
last = calendar.getTime();
if (weekdayIndex.is(count)) {
return last;
}
}
calendar.add(Calendar.DAY_OF_MONTH, 1);
} while (calendar.get(Calendar.MONTH) == month);
if (weekdayIndex.equals(WeekdayIndex.LAST)) {
return last;
}
return null;
}
}
Calling with:
Holidays.FRANCE.getBusinessDayCount(d1, d2);