Converts a provided Persian date to the Julian Day Number (i.e. - Java java.util

Java examples for java.util:Calendar Julian

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Description

Converts a provided Persian date to the Julian Day Number (i.e.

Demo Code

/**/*  w  ww .  j  av  a  2  s  .co m*/
 * Persian Calendar see: http://code.google.com/p/persian-calendar/
   Copyright (C) 2012  Mortezaadi@gmail.com
   PersianCalendarUtils.java
           
   Persian Calendar is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

public class Main{
    public static void main(String[] argv) throws Exception{
        long year = 2;
        int month = 2;
        int day = 2;
        System.out.println(persianToJulian(year,month,day));
    }
    /**
     * Converts a provided Persian (Shamsi) date to the Julian Day Number
     *  (i.e. the number of days since January 1 in the year 4713 BC).
     *  Since the Persian calendar is a highly regular calendar, converting to and from a Julian Day Number
     *   is not as difficult as it looks. Basically it's a mather of dividing, rounding and multiplying.
     *   This routine uses Julian Day Number 1948321 as focal point, since that Julian Day Number
     *    corresponds with 1 Farvardin (1) 1. 
     * @param year int persian year
     * @param month int persian month
     * @param day int persian day
     * @return long
     */
    public static long persianToJulian(long year, int month, int day) {
        return 365L
                * ((ceil(year - 474L, 2820D) + 474L) - 1L)
                + ((long) Math
                        .floor((682L * (ceil(year - 474L, 2820D) + 474L) - 110L) / 2816D))
                + (PersianCalendarConstants.PERSIAN_EPOCH - 1L) + 1029983L
                * ((long) Math.floor((year - 474L) / 2820D))
                + (month < 7 ? 31 * month : 30 * month + 6) + day;
    }
    /**
     * Ceil function in original algorithm
     * @param double1
     * @param double2
     * @return long
     */
    public static long ceil(double double1, double double2) {
        return (long) (double1 - double2 * Math.floor(double1 / double2));
    }
}

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