How can I add business days to the current date in Java?

Question

How can I add business days to the current date in Java?

public Calendar addBusinessDate(Calendar cal, int days) {
//
// code goes over here
//
}


        

Answer 1

Use:

public Calendar addBusinessDate(Calendar cal, int numBusinessDays) {
  int numNonBusinessDays = 0;

  for(int i = 0; i < numBusinessDays; i++) {
    cal.add(Calendar.DATE, 1);

    /*
       It's a Canadian/American custom to get the Monday (sometimes Friday) off
       when a holiday falls on a weekend.
    */
    for(int j = 0; j < holidays; j++) { //holidays is list of dates
      if(cal.getTime() == (Date)holidays.get(j)) {
        numNonBusinessDays++;
      }
    }

    if(cal.get(Calendar.DAY_OF_WEEK) == 1 ||
       cal.get(Calendar.DAY_OF_WEEK) == 7) {
      numNonBusinessDays++;
    }
  }

  if(numNonBusinessDays > 0) {
    cal.add(Calendar.DATE, numNonBusinessDays);
  }

  return cal;
}

You'd have to populate a list of dates in order to handle holidays. There's common ones like New Years, but Thanksgiving is different between Canada & the US for instance. Also mind that holidays can fall on a weekend, so the weekend becomes a 3 day weekend.

Reference:

• Calendar
• Calendar Constant Values

PS: There isn't really a need to return the Calendar instance if you are updating the value as in the example. But it is valid if you want to create a separate Calendar instance, use:

public Calendar addBusinessDate(Calendar cal, int numBusinessDays) {
  Calendar cal2 = Calendar.getInstance();
  cal2.setTime(cal.getTime());

  int numNonBusinessDays = 0;

  for(int i = 0; i < numBusinessDays; i++) {
    cal2.add(Calendar.DATE, 1);

    /*
       It's a Canadian/American custom to get the Monday (sometimes Friday) off
       when a holiday falls on a weekend.
    */
    for(int j = 0; j < holidays; j++) { //holidays is list of dates
      if(cal2.getTime() == (Date)holidays.get(j)) {
        numNonBusinessDays++;
      }
    }

    if(cal2.get(Calendar.DAY_OF_WEEK) == 1 ||
       cal2.get(Calendar.DAY_OF_WEEK) == 7) {
      numNonBusinessDays++;
    }
  }

  if(numNonBusinessDays > 0) {
    cal2.add(Calendar.DATE, numNonBusinessDays);
  }

  return cal2;
}

Answer 2

This algorithm calculates the next business date for a given date (business days are from monday to friday in my country), you can adapt it to iterate the number of days you need to add.

public Calendar nextBusinessDate(Calendar cal) {

    List<Calendar> holidays = ********
    // Here get list of holidays from DB or some other service...

    GregorianCalendar calCp = new GregorianCalendar();
    calCp.setTime(cal.getTime());
    calCp.add(Calendar.DAY_OF_MONTH, 1);

    boolean isSaturday = (calCp.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY);
    boolean isSunday = (calCp.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY);
    boolean isHoliday = holidays.contains(calCp);

    while (isSaturday || isSunday || isHoliday) {
      if (isSaturday) {
          calCp.add(Calendar.DAY_OF_MONTH, +2); // is saturday, make it monday
        } else {
        if (isSunday) {
            calCp.add(Calendar.DAY_OF_MONTH, +1); // is sunday, make it monday
        } else {
            if (isHoliday) {
                 calCp.add(Calendar.DAY_OF_MONTH, +1); // is holiday, make it next day
               }
            }
        }
      calCp = new GregorianCalendar();
      calCp.setTime(cal.getTime());
      isSaturday = (calCp.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY);
      isSunday = (calCp.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY);
    isHoliday = holidays.contains(calCp);
    } // end while

    return calCp;
}