java.lang.Object
- jodd.time.JulianDate

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable
```
public class JulianDate
extends java.lang.Object
implements java.io.Serializable, java.lang.Cloneable
```
Julian Date stamp, for high precision calculations. Julian date is a real number and it basically consists 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 Also:

TimeUtil, Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`protected double`	`fraction`	Fraction part of the Julian Date (JD).
`protected int`	`integer`	Integer part of the Julian Date (JD).
`static JulianDate`	`JD_1970`	Julian Date for 1970-01-01T00:00:00 (Thursday).
`static JulianDate`	`JD_2001`	Julian Date for 2001-01-01T00:00:00 (Monday).
`private static JulianDate`	`JD_MJD_0`	Julian Date when Modified Julian Date (MJD) is 0.
`private static JulianDate`	`JD_RJD_0`	Julian Date when Reduced Julian Date (RJD) is 0.
`private static JulianDate`	`JD_TJD_0`	Julian Date when Truncated Julian Date (TJD) is 0.

Constructor Summary

Constructors
Constructor Description

JulianDate(int i, double f)
Creates JD from both integer and fractional part using normalization.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`JulianDate`	`add(double delta)`	Adds a double delta value and returns a new instance.
`JulianDate`	`add(JulianDate jds)`	Adds two JD and returns a new instance.
`protected JulianDate`	`clone()`
`int`	`daysBetween(JulianDate otherDate)`	Calculates the number of days between two dates.
`int`	`daysSpan(JulianDate otherDate)`	Returns span between two days.
`boolean`	`equals(java.lang.Object object)`
`static JulianDate`	`fromModifiedJulianDate(double mjd)`	Returns the JD from a Modified Julian Date (MJD), where date starts from midnight rather than noon.
`static JulianDate`	`fromReducedJulianDate(double rjd)`	Returns the JD from a Reduced Julian Date (RJD), used by astronomers.
`static JulianDate`	`fromTruncatedJulianDate(double tjd)`	Returns the JD from a Truncated Julian Day (TJD), introduced by NASA for the space program.
`double`	`getFraction()`	Returns the fraction part of Julian Date (JD).
`int`	`getInteger()`	Returns integer part of the Julian Date (JD).
`int`	`getJulianDayNumber()`	Returns JDN.
`JulianDate`	`getModifiedJulianDate()`	Returns Modified Julian Date (MJD), where date starts from midnight rather than noon.
`JulianDate`	`getReducedJulianDate()`	Returns Reduced Julian Date (RJD), used by astronomers.
`int`	`getSignificantFraction()`	Calculates and returns significant fraction only as an int.
`JulianDate`	`getTruncatedJulianDate()`	Returns Truncated Julian Day (TJD), introduced by NASA for the space program.
`int`	`hashCode()`
`static JulianDate`	`now()`
`static JulianDate`	`of(double jd)`	Creates JD from a double value.
`static JulianDate`	`of(int i, double f)`
`static JulianDate`	`of(int year, int month, int day, int hour, int minute, int second, int millisecond)`
`static JulianDate`	`of(long milliseconds)`
`static JulianDate`	`of(java.math.BigDecimal bd)`
`static JulianDate`	`of(java.time.Instant instant)`
`static JulianDate`	`of(java.time.LocalDate localDate)`
`static JulianDate`	`of(java.time.LocalDateTime localDateTime)`
`JulianDate`	`sub(double delta)`	Subtracts a double from current instance and returns a new instance.
`JulianDate`	`sub(JulianDate jds)`	Subtracts a JD from current instance and returns a new instance.
`java.math.BigDecimal`	`toBigDecimal()`	Returns `BigDecimal` value of JD.
`double`	`toDouble()`	Returns `double` value of JD.
`java.time.Instant`	`toInstant()`	Converts to Instant.
`java.time.LocalDateTime`	`toLocalDateTime()`	Converts to LocalDateTime at UTC.
`long`	`toMilliseconds()`	Converts to milliseconds.
`java.lang.String`	`toString()`	Returns string representation of JD.

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - JD_1970
```
public static final JulianDate JD_1970
```
    Julian Date for 1970-01-01T00:00:00 (Thursday).
  - JD_2001
```
public static final JulianDate JD_2001
```
    Julian Date for 2001-01-01T00:00:00 (Monday).
  - JD_RJD_0
```
private static final JulianDate JD_RJD_0
```
    Julian Date when Reduced Julian Date (RJD) is 0. RJD = JD − 2400000
  - JD_MJD_0
```
private static final JulianDate JD_MJD_0
```
    Julian Date when Modified Julian Date (MJD) is 0. MJD = JD − 2400000.5
  - JD_TJD_0
```
private static final JulianDate JD_TJD_0
```
    Julian Date when Truncated Julian Date (TJD) is 0. TJD began at midnight at the beginning of May 24, 1968 (Friday).
  - integer
```
protected int integer
```
    Integer part of the Julian Date (JD).
  - fraction
```
protected double fraction
```
    Fraction part of the Julian Date (JD). Should be always in [0.0, 1.0) range.
- Constructor Detail
  - JulianDate
```
public JulianDate(int i,
                  double f)
```
    Creates JD from both integer and fractional part using normalization. Normalization means that if fractional part is out of range, values will be correctly fixed.
    
    Parameters:
    
    i - integer part
    
    f - fractional part should be in range [0.0, 1.0)
- Method Detail
  - of
```
public static JulianDate of(double jd)
```
    Creates JD from a double value. CAUTION: double values may not be suited for precision math. If precision is needed, consider passing in a BigDecimal instead.
  - of
```
public static JulianDate of(java.time.LocalDateTime localDateTime)
```
  - of
```
public static JulianDate of(java.time.LocalDate localDate)
```
  - of
```
public static JulianDate of(java.time.Instant instant)
```
  - of
```
public static JulianDate of(long milliseconds)
```
  - of
```
public static JulianDate of(int i,
                            double f)
```
  - of
```
public static JulianDate of(int year,
                            int month,
                            int day,
                            int hour,
                            int minute,
                            int second,
                            int millisecond)
```
  - of
```
public static JulianDate of(java.math.BigDecimal bd)
```
  - now
```
public static JulianDate now()
```
  - getInteger
```
public int getInteger()
```
    Returns integer part of the Julian Date (JD).
  - getFraction
```
public double getFraction()
```
    Returns the fraction part of Julian Date (JD). Returned value is always in [0.0, 1.0) range.
  - getSignificantFraction
```
public int getSignificantFraction()
```
    Calculates and returns significant fraction only as an int.
  - getJulianDayNumber
```
public int getJulianDayNumber()
```
    Returns JDN. Note that JDN is not equal to integer. It is calculated by rounding to the nearest integer.
  - toDouble
```
public double toDouble()
```
    Returns double value of JD. CAUTION: double values may not be suited for precision math due to loss of precision.
  - toBigDecimal
```
public java.math.BigDecimal toBigDecimal()
```
    Returns BigDecimal value of JD.
  - toString
```
public java.lang.String toString()
```
    Returns string representation of JD.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    Julian date as string
  - toMilliseconds
```
public long toMilliseconds()
```
    Converts to milliseconds.
  - toInstant
```
public java.time.Instant toInstant()
```
    Converts to Instant.
  - toLocalDateTime
```
public java.time.LocalDateTime toLocalDateTime()
```
    Converts to LocalDateTime at UTC.
  - add
```
public JulianDate add(JulianDate jds)
```
    Adds two JD and returns a new instance.
  - add
```
public JulianDate add(double delta)
```
    Adds a double delta value and returns a new instance.
  - sub
```
public JulianDate sub(JulianDate jds)
```
    Subtracts a JD from current instance and returns a new instance.
  - sub
```
public JulianDate sub(double delta)
```
    Subtracts a double from current instance and returns a new instance.
  - daysBetween
```
public int daysBetween(JulianDate otherDate)
```
    Calculates the number of days between two dates. Returned value is always positive.
  - daysSpan
```
public int daysSpan(JulianDate otherDate)
```
    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).
  - equals
```
public boolean equals(java.lang.Object object)
```
    Overrides:
    
    equals in class java.lang.Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - clone
```
protected JulianDate clone()
```
    Overrides:
    
    clone in class java.lang.Object
  - getReducedJulianDate
```
public JulianDate getReducedJulianDate()
```
    Returns Reduced Julian Date (RJD), used by astronomers. RJD = JD − 2400000
  - getModifiedJulianDate
```
public JulianDate getModifiedJulianDate()
```
    Returns Modified Julian Date (MJD), where date starts from midnight rather than noon. MJD = JD − 2400000.5
  - getTruncatedJulianDate
```
public JulianDate getTruncatedJulianDate()
```
    Returns Truncated Julian Day (TJD), introduced by NASA for the space program. TJD began at midnight at the beginning of May 24, 1968 (Friday).
  - fromReducedJulianDate
```
public static JulianDate fromReducedJulianDate(double rjd)
```
    Returns the JD from a Reduced Julian Date (RJD), used by astronomers. RJD = JD − 2400000
  - fromModifiedJulianDate
```
public static JulianDate fromModifiedJulianDate(double mjd)
```
    Returns the JD from a Modified Julian Date (MJD), where date starts from midnight rather than noon. MJD = JD − 2400000.5
  - fromTruncatedJulianDate
```
public static JulianDate fromTruncatedJulianDate(double tjd)
```
    Returns the JD from a Truncated Julian Day (TJD), introduced by NASA for the space program. TJD began at midnight at the beginning of May 24, 1968 (Friday).

Class JulianDate

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

JD_1970

JD_2001

JD_RJD_0

JD_MJD_0

JD_TJD_0

integer

fraction

Constructor Detail

JulianDate

Method Detail

of

of

of

of

of

of

of

of

now

getInteger

getFraction

getSignificantFraction

getJulianDayNumber

toDouble

toBigDecimal

toString

toMilliseconds

toInstant

toLocalDateTime

add

add

sub

sub

daysBetween

daysSpan

equals

hashCode

clone

getReducedJulianDate

getModifiedJulianDate

getTruncatedJulianDate

fromReducedJulianDate

fromModifiedJulianDate

fromTruncatedJulianDate