jodd.datetime
Class JulianDateStamp

java.lang.Object
  jodd.datetime.JulianDateStamp

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class JulianDateStamp
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 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 numerics 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 intger part of julian date real number has to be preserved.

See Also:

TimeUtil, JDateTime, DateTimeStamp, Serialized Form

Field Summary

protected double	fraction Fraction part of the Julian Date (JD).
protected int	integer Integer part of the Julian Date (JD).

Constructor Summary

JulianDateStamp()
Default empty constructor.

JulianDateStamp(java.math.BigDecimal bd)
Creates JD from BigDecimal.

JulianDateStamp(double jd)
Creates JD from a double.

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

Method Summary

JulianDateStamp	add(double delta) Adds a double to current instance.
JulianDateStamp	add(JulianDateStamp jds) Adds a JD to current instance.
protected JulianDateStamp	clone()
int	daysBetween(JulianDateStamp otherDate) Calculates the number of days between two dates.
int	daysSpan(JulianDateStamp otherDate) Returns span between two days.
double	doubleValue() Returns double value of JD.
boolean	equals(java.lang.Object object)
double	getFraction()
int	getInteger()
int	getJulianDayNumber() Returns JDN.
JulianDateStamp	getModifiedJulianDate()
JulianDateStamp	getReducedJulianDate()
JulianDateStamp	getTruncatedJulianDate()
int	hashCode()
void	set(double jd)
void	set(int i, double f) Sets integer and fractional part with normalization.
void	setModifiedJulianDate(double mjd)
void	setReducedJulianDate(double rjd)
void	setTruncatedJulianDate(double tjd)
JulianDateStamp	sub(double delta) Subtracts a double from current instance.
JulianDateStamp	sub(JulianDateStamp jds) Subtracts a JD from current instance.
java.math.BigDecimal	toBigDecimal() Returns BigDecimal value of JD.
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

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

JulianDateStamp

public JulianDateStamp()

Default empty constructor.

JulianDateStamp

public JulianDateStamp(double jd)

Creates JD from a double.

JulianDateStamp

public JulianDateStamp(int i,
                       double f)

Creates JD from both integer and fractional part using normalization. Normalization occurs when fractional part is out of range.

Parameters:

i - integer part

f - fractional part should be in range [0.0, 1.0)

See Also:

set(int, double)

JulianDateStamp

public JulianDateStamp(java.math.BigDecimal bd)

Creates JD from BigDecimal.

Method Detail

getInteger

public int getInteger()

getFraction

public double getFraction()

getJulianDayNumber

public int getJulianDayNumber()

Returns JDN. Note that JDN is not equal to integer. It is calculated by rounding to the nearest integer.

doubleValue

public double doubleValue()

Returns double value of JD. CAUTION: double values may not be suit 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 integer as string

add

public JulianDateStamp add(JulianDateStamp jds)

Adds a JD to current instance.

add

public JulianDateStamp add(double delta)

Adds a double to current instance.

sub

public JulianDateStamp sub(JulianDateStamp jds)

Subtracts a JD from current instance.

sub

public JulianDateStamp sub(double delta)

Subtracts a double from current instance.

set

public void set(int i,
                double f)

Sets integer and fractional part with normalization. Normalization means that if double is out of range, values will be correctly fixed.

set

public void set(double jd)

daysBetween

public int daysBetween(JulianDateStamp otherDate)

Calculates the number of days between two dates. Returned value is always positive.

daysSpan

public int daysSpan(JulianDateStamp 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 JulianDateStamp clone()

Overrides:

clone in class java.lang.Object

getReducedJulianDate

public JulianDateStamp getReducedJulianDate()

setReducedJulianDate

public void setReducedJulianDate(double rjd)

getModifiedJulianDate

public JulianDateStamp getModifiedJulianDate()

setModifiedJulianDate

public void setModifiedJulianDate(double mjd)

getTruncatedJulianDate

public JulianDateStamp getTruncatedJulianDate()

setTruncatedJulianDate

public void setTruncatedJulianDate(double tjd)