Holiday in date

[Kristol Crawley]

Is it possible to tell if the date is a holiday? I looked through the api for calendar (we're on 1.3.1 btw) and I didn't see anything that looked like it would return that.

[Jason Menard]

Java does not provide this functionality automatically. It will require some work on your part. Check out JavaWorld's Tips 'N Tricks Java Tip 44: Calculating holidays and their observances for some more info.

[Kristol Crawley]

I figured it'd be messy!
Thank you Jason!

[Michael Dunn]

here's one I was working on some time ago (I'm not from the US so I'm not entirely sure I have the parameters of the holidays correct)
easter calculation is close, but is incorrect (this is when I stopped), you might be able to add a tweak or two, to get it right.

import java.util.*;
import java.text.*;
class Holidays
{
public static Calendar cal = Calendar.getInstance();
  public static String holidays[][] = new String [13][32];
  public static DateFormat df = new SimpleDateFormat( "EEEE, d MMMM yyyy" );
public static void main(String args[])
{
    int year = Integer.parseInt(args[0]);
    final String data[][] =
      {{"0","1","1","New Year's Day"},{"3","2","1","Martin Luther King Jr Day"},
      {"3","2","2","President's Day"},{"5","2","5","Memorial Day"},
      {"0","4","7","Independence Day"},{"1","2","9","Labor Day"},
      {"2","2","10","Columbus Day"},{"0","11","11","Veteran's Day"},
      {"4","5","11","Thansgiving Day"},{"0","25","12","Christmas Day"}};
    for(int i = 0; i < data.length; i++)
    {
      setHolidayDate(Integer.parseInt(data[i][0]), Integer.parseInt(data[i][1]),
                     Integer.parseInt(data[i][2]), year, data[i][3]);
    }
    setEaster(year);
    holidays[0][0] = holidays[12][31]; /*for 1 Jan falling on saturday*/
    holidays[12][31] = "";             /*ditto */
    for(int i = 0; i < 13; i++)
    {
      for(int ii = 0; ii < 32; ii++)
      {
        if(holidays[i][ii] != null) System.out.println(holidays[i][ii]);
      }
    }
  }
public static void setHolidayDate(int week, int day, int month, int year, String name)
{
  int dayOfWeek;
    if(week == 0) /*it's a day of the month eg 25 December*/
{
      cal.set(year,month - 1,day);
  dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
      if(dayOfWeek == 7) cal.set(year,month - 1,day - 1);
  else if(dayOfWeek == 1) cal.set(year,month - 1,day + 1);
    }
    else if(week < 5)/*it's a day of the week, in the month eg 3rd Monday in January*/
    {
      cal.set(year, month - 1, 1);
      dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
      if(dayOfWeek <= day) cal.set(year, month - 1, 1 - dayOfWeek + day + ((week - 1) * 7));
      else cal.set(year, month - 1, 1 - dayOfWeek + day + (week * 7));
    }
    else               /*a day in the last week of the month*/
    {                  /*set up as 5th week eg last monday in may*/
      cal.set(year, month - 1, 1);
  dayOfWeek = cal.get(Calendar.DAY_OF_WEEK);
  do
  {
    day += 7;
        cal.set(year, month - 1, 1 - dayOfWeek + day);
  }while(cal.get(Calendar.MONTH) == month - 1);
      cal.set(year, month - 1, 1 - dayOfWeek + day - 7);
    }
 /* set the holiday date*/
  holidays[cal.get(Calendar.MONTH) + 1] [cal.get(Calendar.DAY_OF_MONTH)] =
      (String)df.format(cal.getTime()) + " " + name;
  }
  public static void setEaster(int year)
  {
     int y =  ((int)((18.37 * (year % 19)) - 6 + .5)) % 29;
     int x = ((year - 1900) * 365 + (int) (year - 1900)/4 + 59 + y + 1) % 7;
     if(x == 0) x = 7;
     cal.set(year, 2, y - x + 29 - 2); /* good friday*/
     holidays[cal.get(Calendar.MONTH) + 1] [cal.get(Calendar.DAY_OF_MONTH)] =
      (String)df.format(cal.getTime()) + " " + "Good Friday";
     cal.set(year, 2, y - x + 29 + 1); /* easter monday*/
     holidays[cal.get(Calendar.MONTH) + 1] [cal.get(Calendar.DAY_OF_MONTH)] =
      (String)df.format(cal.getTime()) + " " + "Easter Monday";
  }
}