net.time4j.base

Class GregorianMath

java.lang.Object

net.time4j.base.GregorianMath

public final class GregorianMath
extends Object

Contains some calendrical tools for the rules of gregorian calendar.

Author:

Meno Hochschild

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_YEAR Maximum of supported year range (999999999).
static int	MIN_YEAR Minimum of supported year range (-999999999).

Method Summary

Modifier and Type	Method and Description
static void	checkDate(int year, int month, int dayOfMonth) Checks the range limits of date values according to the rules of gregorian calendar.
static int	getDayOfWeek(int year, int month, int dayOfMonth) Returns the day of week for given gregorian date.
static int	getLengthOfMonth(int year, int month) Determines the maximum length of month in days dependent on given year (leap years!)
static boolean	isLeapYear(int year) Queries if given year is a gregorian leap year.
static boolean	isValid(int year, int month, int dayOfMonth) Queries if given values form a well defined gregorian date.
static int	readDayOfMonth(long packedDate) Returns the day of month from given binary compressed date.
static int	readMonth(long packedDate) Returns the month from given binary compressed date.
static int	readYear(long packedDate) Returns the year from given binary compressed date.
static long	toMJD(GregorianDate date) Calculates the modified Julian date.
static long	toMJD(int year, int month, int dayOfMonth) Calculates the modified Julian date.
static long	toPackedDate(long mjd) Calculates the gregorian Date based on given modified julian date in binary compressed format.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MIN_YEAR

public static final int MIN_YEAR

Minimum of supported year range (-999999999).

See Also:

Constant Field Values

MAX_YEAR

public static final int MAX_YEAR

Maximum of supported year range (999999999).

See Also:

Constant Field Values

Method Detail

isLeapYear

public static boolean isLeapYear(int year)

Queries if given year is a gregorian leap year.

Parameters:

year - number of proleptic year

Returns:

true if it is a leap year else false

getLengthOfMonth

public static int getLengthOfMonth(int year,
                                   int month)

Determines the maximum length of month in days dependent on given year (leap years!) and month.

Parameters:

year - proleptic iso year

month - gregorian month (1-12)

Returns:

length of month in days

Throws:

IllegalArgumentException - if month is out of range (1-12)

isValid

public static boolean isValid(int year,
                              int month,
                              int dayOfMonth)

Queries if given values form a well defined gregorian date.

This method only checks the range limits, not if the date is historically correct.

Parameters:

year - proleptic iso year [(-999999999) - 999999999]

month - gregorian month (1-12)

dayOfMonth - day of month (1-31)

Returns:

true if valid else false

See Also:

checkDate(int, int, int)

checkDate

public static void checkDate(int year,
                             int month,
                             int dayOfMonth)

Checks the range limits of date values according to the rules of gregorian calendar.

Parameters:

year - proleptic iso year [(-999999999) - 999999999]

month - gregorian month (1-12)

dayOfMonth - day of month (1-31)

Throws:

IllegalArgumentException - if any argument is out of range

See Also:

isValid(int, int, int)

getDayOfWeek

public static int getDayOfWeek(int year,
                               int month,
                               int dayOfMonth)

Returns the day of week for given gregorian date.

This method is based on ISO-8601 and assumes that Monday is the first day of week.

Parameters:

year - proleptic iso year

month - gregorian month (1-12)

dayOfMonth - day of month (1-31)

Returns:

day of week (monday = 1, ..., sunday = 7)

Throws:

IllegalArgumentException - if the month or the day are out of range

readYear

public static int readYear(long packedDate)

Returns the year from given binary compressed date.

Parameters:

packedDate - packed date in binary format

Returns:

proleptic iso year

See Also:

toPackedDate(long)

readMonth

public static int readMonth(long packedDate)

Returns the month from given binary compressed date.

Parameters:

packedDate - packed date in binary format

Returns:

gregorian month (1-12)

See Also:

toPackedDate(long)

readDayOfMonth

public static int readDayOfMonth(long packedDate)

Returns the day of month from given binary compressed date.

Parameters:

packedDate - packed date in binary format

Returns:

day of month (1-31)

See Also:

toPackedDate(long)

toPackedDate

public static long toPackedDate(long mjd)

Calculates the gregorian Date based on given modified julian date in binary compressed format.

Applications can extract the single date components from the result of this method by mean of readYear(), readMonth() and readDayOfMonth().

Parameters:

mjd - days since [1858-11-17] (modified Julian date)

Returns:

packed date in binary format

Throws:

IllegalArgumentException - if the calculated year is not in range [(-999999999)-999999999)]

See Also:

readYear(long), readMonth(long), readDayOfMonth(long)

toMJD

public static long toMJD(GregorianDate date)

Calculates the modified Julian date.

Parameters:

date - gregorian date

Returns:

days since [1858-11-17] (modified Julian date)

Throws:

IllegalArgumentException - if the argument is out of range

See Also:

toMJD(int, int, int)

toMJD

public static long toMJD(int year,
                         int month,
                         int dayOfMonth)

Calculates the modified Julian date.

Parameters:

year - proleptic iso year [(-999999999) - 999999999]

month - gregorian month (1-12)

dayOfMonth - day of month in range (1-31)

Returns:

days since [1858-11-17] (modified Julian date)

Throws:

IllegalArgumentException - if any argument is out of range