Is a calendar or date after/before today or within a number of days in the future

 
import java.util.Calendar;
import java.util.Date;

public class Main {
  public static boolean isBeforeDay(Date date1, Date date2) {
    if (date1 == null || date2 == null) {
      throw new IllegalArgumentException("The dates must not be null");
    }
    Calendar cal1 = Calendar.getInstance();
    cal1.setTime(date1);
    Calendar cal2 = Calendar.getInstance();
    cal2.setTime(date2);
    return isBeforeDay(cal1, cal2);
  }

  public static boolean isBeforeDay(Calendar cal1, Calendar cal2) {
    if (cal1 == null || cal2 == null) {
      throw new IllegalArgumentException("The dates must not be null");
    }
    if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA))
      return true;
    if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA))
      return false;
    if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR))
      return true;
    if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR))
      return false;
    return cal1.get(Calendar.DAY_OF_YEAR) < cal2.get(Calendar.DAY_OF_YEAR);
  }

  public static boolean isAfterDay(Date date1, Date date2) {
    if (date1 == null || date2 == null) {
      throw new IllegalArgumentException("The dates must not be null");
    }
    Calendar cal1 = Calendar.getInstance();
    cal1.setTime(date1);
    Calendar cal2 = Calendar.getInstance();
    cal2.setTime(date2);
    return isAfterDay(cal1, cal2);
  }

  public static boolean isAfterDay(Calendar cal1, Calendar cal2) {
    if (cal1 == null || cal2 == null) {
      throw new IllegalArgumentException("The dates must not be null");
    }
    if (cal1.get(Calendar.ERA) < cal2.get(Calendar.ERA))
      return false;
    if (cal1.get(Calendar.ERA) > cal2.get(Calendar.ERA))
      return true;
    if (cal1.get(Calendar.YEAR) < cal2.get(Calendar.YEAR))
      return false;
    if (cal1.get(Calendar.YEAR) > cal2.get(Calendar.YEAR))
      return true;
    return cal1.get(Calendar.DAY_OF_YEAR) > cal2.get(Calendar.DAY_OF_YEAR);
  }

  public static boolean isWithinDaysFuture(Date date, int days) {
    if (date == null) {
      throw new IllegalArgumentException("The date must not be null");
    }
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    return isWithinDaysFuture(cal, days);
  }

  public static boolean isWithinDaysFuture(Calendar cal, int days) {
    if (cal == null) {
      throw new IllegalArgumentException("The date must not be null");
    }
    Calendar today = Calendar.getInstance();
    Calendar future = Calendar.getInstance();
    future.add(Calendar.DAY_OF_YEAR, days);
    return (isAfterDay(cal, today) && !isAfterDay(cal, future));
  }

}