Java Month Number Get eemonth(double serial_number)

Description

eemonth

License

Apache License

Declaration

public static final double eemonth(double serial_number) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

public class Main {
    public static final long GREGORIAN_EPOCH = 1721425;

    public static final double eemonth(double serial_number) {
        if (!isFinite(serial_number)) {
            return Double.NaN;
        }/*w w w .j av a2s  . com*/
        if (serial_number < 1) {
            return 1;
        }
        if (serial_number > 60) {
            serial_number--;
        }
        long[] res = jd_to_gregorian((long) serial_number + 2415020);
        return res[1];
    }

    public static final boolean isFinite(double x) {
        return !(Double.isInfinite(x) || Double.isNaN(x));
    }

    public static final long[] jd_to_gregorian(long jd) {
        long wjd, depoch, quadricent, dqc, cent, dcent, quad, dquad, yindex, year, yearday, leapadj;
        wjd = jd;
        depoch = wjd - GREGORIAN_EPOCH - 1;
        quadricent = (depoch / 146097);
        dqc = mod_long(depoch, 146097);
        cent = (dqc / 36524);
        dcent = mod_long(dqc, 36524);
        quad = (dcent / 1461);
        dquad = mod_long(dcent, 1461);
        yindex = (dquad / 365);
        year = (quadricent * 400) + (cent * 100) + (quad * 4) + yindex;
        if (!((cent == 4) || (yindex == 4))) {
            year++;
        }
        yearday = wjd - gregorian_to_jd(year, 1, 1);
        leapadj = ((wjd < gregorian_to_jd(year, 3, 1)) ? 0 : (leap_gregorian(year) ? 1 : 2));
        long month = ((((yearday + leapadj) * 12) + 373) / 367);
        long day = (wjd - gregorian_to_jd(year, month, 1)) + 1;
        return new long[] { year, month, day };
    }

    private static final long mod_long(long n, long d) {
        return n - d * (n / d);
    }

    public static final long gregorian_to_jd(long year, long month, long day) {
        return GREGORIAN_EPOCH + (365 * (year - 1)) + ((year - 1) / 4) + (-((year - 1) / 100)) + ((year - 1) / 400)
                + ((((367 * month) - 362) / 12) + ((month <= 2) ? 0 : (leap_gregorian(year) ? -1 : -2)) + day);
    }

    public static final boolean leap_gregorian(long year) {
        return ((year % 4) == 0) && (!(((year % 100) == 0) && ((year % 400) != 0)));
    }
}

Related

1. getInitialsByMonthNumber(String monthNumber)
2. getMonthDigit(String month)
3. getMonthIds()
4. getMonthIndex(String str)