Question

I am able to add 102 days to any date I input, but now the problem is, it should be 102 week days (excluding weekends). How can I do that?

Here’s my code for just adding 102 days:

private void txtStartKeyReleased(java.awt.event.KeyEvent evt) {
    try {    
        Date date1 = new SimpleDateFormat("yyyy-MM-dd").parse(txtStart.getText());

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");     
        Calendar cal  = Calendar.getInstance();
        cal.setTime(date1);
        cal.add(Calendar.DATE, 102);
        String expDateString = sdf.format(cal.getTime());
        txtExpiry.setText(expDateString);
    } catch (ParseException ex) {
        Logger.getLogger(ClientInfo.class.getName()).log(Level.SEVERE, null, ex);
    } 
}

Answer 1

This should add weekdays week days (weekends are ignored) onto a date. If you pass 0 for weekdays it will get the next working day. So, Saturday + 1 weekday = Tuesday.

private static Date addWeekdaysToDate(Date date, int weekdays) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    int originalDayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
    int numWeeks = weekdays / 5;
    int remainderDays = weekdays % 5;
    cal.add(Calendar.DAY_OF_MONTH, numWeeks * 7 + remainderDays);

    int adjustmentDays = 0;
    if (originalDayOfWeek == Calendar.SUNDAY) {
        adjustmentDays = 1;
    } else if (originalDayOfWeek + remainderDays > Calendar.FRIDAY) {
        adjustmentDays = 2;
    }
    cal.add(Calendar.DAY_OF_MONTH, adjustmentDays);
    return cal.getTime();
}

EDIT:

In your code, just replace with the following:

private static Date addWeekdaysToDate(Date date, int weekdays) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    int originalDayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
    int numWeeks = weekdays / 5;
    int remainderDays = weekdays % 5;
    cal.add(Calendar.DAY_OF_MONTH, numWeeks * 7 + remainderDays);

    int adjustmentDays = 0;
    if (originalDayOfWeek == Calendar.SUNDAY) {
        adjustmentDays = 1;
    } else if (originalDayOfWeek + remainderDays > Calendar.FRIDAY) {
        adjustmentDays = 2;
    }
    cal.add(Calendar.DAY_OF_MONTH, adjustmentDays);
    return cal.getTime();
}

private static SimpleDateFormat inputDateFormat = new SimpleDateFormat("yyyy-MM-dd");
private void txtStartKeyReleased(java.awt.event.KeyEvent evt) {
    try {
        txtExpiry.setText(
            inputDateFormat.format(
                addWeekdaysToDate(inputDateFormat.parse(txtStart.getText()), 102)
            )
        );
    } catch (ParseException ex) {
        Logger.getLogger(ClientInfo.class.getName()).log(Level.SEVERE, null, ex);
    } 
}