jodd.time.JulianDate Maven / Gradle / Ivy
// Copyright (c) 2003-present, Jodd Team (http://jodd.org)
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package jodd.time;
import java.io.Serializable;
import java.math.BigDecimal;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.Objects;
import static jodd.time.TimeUtil.MILLIS_IN_DAY;
/**
* Julian Date stamp, for high precision calculations. Julian date is a real
* number and it basically consist of two parts: integer and fraction. Integer
* part carries date information, fraction carries time information.
*
*
* The Julian day or Julian day number (JDN) is the (integer) number of days that
* have elapsed since Monday, January 1, 4713 BC in the proleptic Julian calendar 1.
* That day is counted as Julian day zero. Thus the multiples of 7 are Mondays.
* Negative values can also be used.
*
*
* The Julian Date (JD) is the number of days (with decimal fraction of the day) that
* have elapsed since 12 noon Greenwich Mean Time (UT or TT) of that day.
* Rounding to the nearest integer gives the Julian day number.
*
* For calculations that will have time precision of 1e-3 seconds, both
* fraction and integer part must have enough digits in it. The problem is
* that integer part is big and, on the other hand fractional is small, and
* since final julian date is a sum of this two values, some fraction
* numerals may be lost. Therefore, for higher precision both
* fractional and integer part of julian date real number has to be
* preserved.
*
* This class stores the unmodified fraction part, but not all digits
* are significant! For 1e-3 seconds precision, only 8 digits after
* the decimal point are significant.
*
* @see TimeUtil
*/
public class JulianDate implements Serializable, Cloneable {
/**
* Julian Date for 1970-01-01T00:00:00 (Thursday).
*/
public static final JulianDate JD_1970 = new JulianDate(2440587, 0.5);
/**
* Julian Date for 2001-01-01T00:00:00 (Monday).
*/
public static final JulianDate JD_2001 = new JulianDate(2451910, 0.5);
public static JulianDate of(final double value) {
return new JulianDate(value);
}
public static JulianDate of(final LocalDateTime localDateTime) {
return of(localDateTime.getYear(),
localDateTime.getMonth().getValue(),
localDateTime.getDayOfMonth(),
localDateTime.getHour(),
localDateTime.getMinute(),
localDateTime.getSecond(),
localDateTime.getNano() / 1_000_000);
}
public static JulianDate of(final LocalDate localDate) {
return of(localDate.getYear(),
localDate.getMonth().getValue(),
localDate.getDayOfMonth(),
0, 0, 0, 0);
}
public static JulianDate of(final long milliseconds) {
int integer = (int) (milliseconds / MILLIS_IN_DAY);
double fraction = (double)(milliseconds % MILLIS_IN_DAY) / MILLIS_IN_DAY;
integer += JD_1970.integer;
fraction += JD_1970.fraction;
return new JulianDate(integer, fraction);
}
public static JulianDate of(final int i, final double f) {
return new JulianDate(i, f);
}
public static JulianDate of(int year, int month, int day, final int hour, final int minute, final int second, final int millisecond) {
// month range fix
if ((month > 12) || (month < -12)) {
month--;
int delta = month / 12;
year += delta;
month -= delta * 12;
month++;
}
if (month < 0) {
year--;
month += 12;
}
// decimal day fraction
double frac = (hour / 24.0) + (minute / 1440.0) + (second / 86400.0) + (millisecond / 86400000.0);
if (frac < 0) { // negative time fix
int delta = ((int)(-frac)) + 1;
frac += delta;
day -= delta;
}
//double gyr = year + (0.01 * month) + (0.0001 * day) + (0.0001 * frac) + 1.0e-9;
double gyr = year + (0.01 * month) + (0.0001 * (day + frac)) + 1.0e-9;
// conversion factors
int iy0;
int im0;
if (month <= 2) {
iy0 = year - 1;
im0 = month + 12;
} else {
iy0 = year;
im0 = month;
}
int ia = iy0 / 100;
int ib = 2 - ia + (ia >> 2);
// calculate julian date
int jd;
if (year <= 0) {
jd = (int)((365.25 * iy0) - 0.75) + (int)(30.6001 * (im0 + 1)) + day + 1720994;
} else {
jd = (int)(365.25 * iy0) + (int)(30.6001 * (im0 + 1)) + day + 1720994;
}
if (gyr >= 1582.1015) { // on or after 15 October 1582
jd += ib;
}
//return jd + frac + 0.5;
return new JulianDate(jd, frac + 0.5);
}
public static JulianDate now() {
return of(LocalDateTime.now());
}
/**
* Integer part of the Julian Date (JD).
*/
protected int integer;
/**
* Returns integer part of the Julian Date (JD).
*/
public int getInteger() {
return integer;
}
/**
* Fraction part of the Julian Date (JD).
* Should be always in [0.0, 1.0) range.
*/
protected double fraction;
/**
* Returns the fraction part of Julian Date (JD).
* Returned value is always in [0.0, 1.0) range.
*/
public double getFraction() {
return fraction;
}
/**
* Calculates and returns significant fraction only as an int.
*/
public int getSignificantFraction() {
return (int) (fraction * 100_000_000);
}
/**
* Returns JDN. Note that JDN is not equal to {@link #integer}. It is calculated by
* rounding to the nearest integer.
*/
public int getJulianDayNumber() {
if (fraction >= 0.5) {
return integer + 1;
}
return integer;
}
/**
* Creates JD from a double.
*/
public JulianDate(final double jd) {
integer = (int) jd;
fraction = jd - (double)integer;
}
/**
* Creates JD from both integer and fractional part using normalization.
* Normalization occurs when fractional part is out of range.
*
* @see #set(int, double)
*
* @param i integer part
* @param f fractional part should be in range [0.0, 1.0)
*/
public JulianDate(final int i, final double f) {
set(i, f);
}
/**
* Creates JD from BigDecimal.
*/
public JulianDate(final BigDecimal bd) {
double d = bd.doubleValue();
integer = (int) d;
fraction = bd.subtract(new BigDecimal(integer)).doubleValue();
}
// ---------------------------------------------------------------- conversion
/**
* Returns double value of JD.
* CAUTION: double values may not be suit for precision math due to
* loss of precision.
*/
public double doubleValue() {
return (double)integer + fraction;
}
/**
* Returns BigDecimal value of JD.
*/
public BigDecimal toBigDecimal() {
return new BigDecimal(integer).add(new BigDecimal(fraction));
}
/**
* Returns string representation of JD.
*
* @return julian integer as string
*/
@Override
public String toString() {
String s = Double.toString(fraction);
int i = s.indexOf('.');
s = s.substring(i);
return integer + s;
}
/**
* Converts to milliseconds.
*/
public long toMilliseconds() {
double then = (fraction - JD_1970.fraction) * MILLIS_IN_DAY;
then += (integer - JD_1970.integer) * MILLIS_IN_DAY;
then += then > 0 ? 1.0e-6 : -1.0e-6;
return (long) then;
}
public LocalDateTime toLocalDateTime() {
int year, month, day;
double frac;
int jd, ka, kb, kc, kd, ke, ialp;
//double JD = jds.doubleValue();//jdate;
//jd = (int)(JD + 0.5); // integer julian date
//frac = JD + 0.5 - (double)jd + 1.0e-10; // day fraction
ka = (int)(fraction + 0.5);
jd = integer + ka;
frac = fraction + 0.5 - ka + 1.0e-10;
ka = jd;
if (jd >= 2299161) {
ialp = (int)(((double)jd - 1867216.25) / (36524.25));
ka = jd + 1 + ialp - (ialp >> 2);
}
kb = ka + 1524;
kc = (int)(((double)kb - 122.1) / 365.25);
kd = (int)((double)kc * 365.25);
ke = (int)((double)(kb - kd) / 30.6001);
day = kb - kd - ((int)((double)ke * 30.6001));
if (ke > 13) {
month = ke - 13;
} else {
month = ke - 1;
}
if ((month == 2) && (day > 28)){
day = 29;
}
if ((month == 2) && (day == 29) && (ke == 3)) {
year = kc - 4716;
} else if (month > 2) {
year = kc - 4716;
} else {
year = kc - 4715;
}
final int time_year = year;
final int time_month = month;
final int time_day = day;
// hour with minute and second included as fraction
double d_hour = frac * 24.0;
final int time_hour = (int) d_hour; // integer hour
// minute with second included as a fraction
double d_minute = (d_hour - (double)time_hour) * 60.0;
final int time_minute = (int) d_minute; // integer minute
double d_second = (d_minute - (double)time_minute) * 60.0;
final int time_second = (int) d_second; // integer seconds
double d_millis = (d_second - (double)time_second) * 1000.0;
// fix calculation errors
final int time_millisecond = (int) (((d_millis * 10) + 0.5) / 10);
return LocalDateTime.of(time_year, time_month, time_day, time_hour, time_minute, time_second, time_millisecond * 1_000_000);
}
// ---------------------------------------------------------------- math
/**
* Adds two JD and returns a new instance.
*/
public JulianDate add(final JulianDate jds) {
int i = this.integer + jds.integer;
double f = this.fraction + jds.fraction;
return new JulianDate(i, f);
}
/**
* Adds a double delta value and returns a new instance.
*/
public JulianDate add(final double delta) {
return new JulianDate(this.integer, this.fraction + delta);
}
/**
* Subtracts a JD from current instance and returns a new instance.
*/
public JulianDate sub(final JulianDate jds) {
int i = this.integer - jds.integer;
double f = this.fraction -jds.fraction;
return new JulianDate(i, f);
}
/**
* Subtracts a double from current instance and returns a new instance.
*/
public JulianDate sub(final double delta) {
return new JulianDate(this.integer, this.fraction - delta);
}
/**
* Sets integer and fractional part with normalization.
* Normalization means that if double is out of range,
* values will be correctly fixed.
*/
private void set(final int i, double f) {
integer = i;
int fi = (int) f;
f -= fi;
integer += fi;
if (f < 0) {
f += 1;
integer--;
}
this.fraction = f;
}
// ---------------------------------------------------------------- between
/**
* Calculates the number of days between two dates. Returned value is always positive.
*/
public int daysBetween(final JulianDate otherDate) {
int difference = daysSpan(otherDate);
return difference >= 0 ? difference : -difference;
}
/**
* Returns span between two days. Returned value may be positive (when this date
* is after the provided one) or negative (when comparing to future date).
*/
public int daysSpan(final JulianDate otherDate) {
int now = getJulianDayNumber();
int then = otherDate.getJulianDayNumber();
return now - then;
}
// ---------------------------------------------------------------- equals & hashCode
@Override
public boolean equals(final Object object) {
if (this == object) {
return true;
}
if (this.getClass() != object.getClass()) {
return false;
}
JulianDate stamp = (JulianDate) object;
return (stamp.integer == this.integer) &&
(Double.compare(stamp.fraction, this.fraction) == 0);
}
@Override
public int hashCode() {
return Objects.hash(integer, fraction);
}
// ---------------------------------------------------------------- clone
@Override
protected JulianDate clone() {
return new JulianDate(this.integer, this.fraction);
}
// ---------------------------------------------------------------- conversion
/**
* Returns Reduced Julian Date (RJD), used by astronomers.
* RJD = JD − 2400000
*/
public JulianDate getReducedJulianDate() {
return new JulianDate(integer - 2400000, fraction);
}
/**
* Returns Modified Julian Date (MJD), where date starts from midnight rather than noon.
* RJD = JD − 2400000.5
*/
public JulianDate getModifiedJulianDate() {
return new JulianDate(integer - 2400000, fraction - 0.5);
}
/**
* Returns Truncated Julian Day (TJD), introduced by NASA for the space program.
* TJD began at midnight at the beginning of May 24, 1968 (Friday).
*/
public JulianDate getTruncatedJulianDate() {
return new JulianDate(integer - 2440000, fraction - 0.5);
}
}