How to get the last business day of the month?

Question

Is there a reliable Brazilian library of holidays that we can integrate and get the last working day of some month?

Anyway, if there is no such library, how could I get the last weekday of any month? (Formatted in a Calendar or a Date.)

Example of code required

Calendar hoje = Calendar.getInstance();
Calendar ultimoDiaUtil = getUltimoDiaUtil(hoje);

Answer 1

You can get the last day of the month by adding -1 day to a date representing the first day of the following month. And if you want the last day of the week, just go back to the days until you find a Friday (if the last day is no longer). In a maximum of two iterations you get the desired day.

It works as long as you don’t consider the holidays.

If you want to consider the holidays, simply blot them out and add one more condition in the loop by checking if the date is not a holiday, if it is a holiday continue to decrease until the condition is not met and falls outside the while.

Implementing @Renan’s idea plus the part of code that checks whether it’s a holiday:

public static void main(String[] args) {
    DateFormat DATE_FORMAT = new SimpleDateFormat("dd/MM/YYYY");
    Calendar hoje = Calendar.getInstance();
    Calendar ultimoDiaUtilDoMes = getUltimoDiaUtilDoMes(hoje);
    System.out.println(DATE_FORMAT.format(ultimoDiaUtilDoMes.getTime()));
}
public static Calendar getUltimoDiaUtilDoMes(Calendar calendar) {
    //muda a data da variável para o último dia do mês
    calendar.add(Calendar.MONTH, 1);  
    calendar.set(Calendar.DAY_OF_MONTH, 1);  
    calendar.add(Calendar.DATE, -1);
    //enquanto for sábado, domingo ou feriado
    while(calendar.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY ||
            calendar.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY || 
            ehFeriado(calendar)) {
        //decrementa a data em um dia
        calendar.add(Calendar.DATE, -1);            
    }
    return calendar;
}
public static boolean ehFeriado(Calendar calendar) {
    Calendar feriado = Calendar.getInstance();
    //considerando 30 de abril como feriado
    feriado.set(calendar.get(Calendar.YEAR), Calendar.APRIL, 30);
    if(calendar.get(Calendar.DAY_OF_YEAR) == feriado.get(Calendar.DAY_OF_YEAR)) {
        return true;
    }
    else {
        return false;
    }
}

Returns:

29/04/2014

'Cause my code says today’s a holiday, so it showed yesterday’s date.

For the comparison made in the code:

calendar.get(Calendar.DAY_OF_YEAR) == feriado.get(Calendar.DAY_OF_YEAR)

working out it is necessary that the holiday year be set as the same year of the date it will compare, so:

feriado.set(
    calendar.get(Calendar.YEAR), //ano de feriado igual ao ano de calendar
    Calendar.APRIL, //constante estática da classe Calendar
    30);

for the calendar.get(Calendar.DAY_OF_YEAR) returns a integer that says what is the day of that year, so if it is set April 30 of a year any would give difference of a day if compare the date of a leap year with the same date of a non-leap year.

To consider the holidays whose date varies from year to year one must discover the account that is made and implement it for example in a method ehFeriadoQueVaria() and add it to while().

Edition for future reference:

Schedule of Holidays made available by Google in format XML.

Answer 2

Calendar c = Calendar.getInstance();
    //alterar para o mes de abril
    c.set(Calendar.MONDAY, Calendar.APRIL);
    //pega o ultimo dia do mes de abril
    int ultimoDia =c.getActualMaximum(Calendar.DAY_OF_MONTH);

Answer 3

Not to follow too large and complex codes, I suggest, this code made by me, and you suggest to follow the tutorials on the Oracle site itself!

import java.time.LocalDate;

public class testee {

    public static void main(String[] args) {
        System.out.println("primeiro dia do mês: " + principioDoMes(LocalDate.now()));
        System.out.println("ultimo dia do mês: " + fimDoMes(LocalDate.now()));
    }

    private static LocalDate principioDoMes(LocalDate l) {

        String local = l.toString();
        int ano = Integer.parseInt(local.split("-")[0]);
        int mes = Integer.parseInt(local.split("-")[1]);

        return LocalDate.of(ano, mes, 1);
    }

    private static LocalDate fimDoMes(LocalDate l) {
        return principioDoMes(l.plusMonths(1)).minusDays(1);
    }
}