Package org.joda.time

Class DateTimeUtils

java.lang.Object

org.joda.time.DateTimeUtils

public class DateTimeUtils
extends java.lang.Object

DateTimeUtils provide public utility methods for the date-time library.

DateTimeUtils uses shared static variables which are declared as volatile for thread-safety. These can be changed during the lifetime of the application however doing so is generally a bad idea.

Since:

1.0

Author:

Stephen Colebourne

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	DateTimeUtils.MillisProvider	A millisecond provider, allowing control of the system clock.

Field Summary

Fields

Modifier and Type	Field	Description
static DateTimeUtils.MillisProvider	SYSTEM_MILLIS_PROVIDER	The singleton instance of the system millisecond provider.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DateTimeUtils()	Restrictive constructor

Method Summary

Modifier and Type	Method	Description
static long	currentTimeMillis()	Gets the current time in milliseconds.
static long	fromJulianDay(double julianDay)	Creates a date-time from a Julian Day.
static Chronology	getChronology(Chronology chrono)	Gets the chronology handling null.
static java.text.DateFormatSymbols	getDateFormatSymbols(java.util.Locale locale)	Gets the DateFormatSymbols based on the given locale.
static java.util.Map<java.lang.String,DateTimeZone>	getDefaultTimeZoneNames()	Gets the default map of time zone names.
static long	getDurationMillis(ReadableDuration duration)	Gets the millisecond duration from the specified duration object handling null.
static Chronology	getInstantChronology(ReadableInstant instant)	Gets the chronology from the specified instant object handling null.
static long	getInstantMillis(ReadableInstant instant)	Gets the millisecond instant from the specified instant object handling null.
static Chronology	getIntervalChronology(ReadableInstant start, ReadableInstant end)	Gets the chronology from the specified instant based interval handling null.
static Chronology	getIntervalChronology(ReadableInterval interval)	Gets the chronology from the specified interval object handling null.
static PeriodType	getPeriodType(PeriodType type)	Gets the period type handling null.
static ReadableInterval	getReadableInterval(ReadableInterval interval)	Gets the interval handling null.
static DateTimeZone	getZone(DateTimeZone zone)	Gets the zone handling null.
static boolean	isContiguous(ReadablePartial partial)	Checks whether the partial is contiguous.
static void	setCurrentMillisFixed(long fixedMillis)	Sets the current time to return a fixed millisecond time.
static void	setCurrentMillisOffset(long offsetMillis)	Sets the current time to return the system time plus an offset.
static void	setCurrentMillisProvider(DateTimeUtils.MillisProvider millisProvider)	Sets the provider of the current time to class specified.
static void	setCurrentMillisSystem()	Resets the current time to return the system time.
static void	setDefaultTimeZoneNames(java.util.Map<java.lang.String,DateTimeZone> names)	Sets the default map of time zone names.
static double	toJulianDay(long epochMillis)	Calculates the astronomical Julian Day for an instant.
static long	toJulianDayNumber(long epochMillis)	Calculates the astronomical Julian Day Number for an instant.

Methods inherited from class java.lang.Object

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

Field Detail

SYSTEM_MILLIS_PROVIDER

public static final DateTimeUtils.MillisProvider SYSTEM_MILLIS_PROVIDER

The singleton instance of the system millisecond provider.

Constructor Detail

DateTimeUtils

protected DateTimeUtils()

Restrictive constructor

Method Detail

currentTimeMillis

public static final long currentTimeMillis()

Gets the current time in milliseconds.

By default this returns System.currentTimeMillis(). This may be changed using other methods in this class.

Returns:

the current time in milliseconds from 1970-01-01T00:00:00Z

setCurrentMillisSystem

public static final void setCurrentMillisSystem()
                                         throws java.lang.SecurityException

Resets the current time to return the system time.

This method changes the behaviour of currentTimeMillis(). Whenever the current time is queried, System.currentTimeMillis() is used.

Throws:

java.lang.SecurityException - if the application does not have sufficient security rights

setCurrentMillisFixed

public static final void setCurrentMillisFixed(long fixedMillis)
                                        throws java.lang.SecurityException

Sets the current time to return a fixed millisecond time.

This method changes the behaviour of currentTimeMillis(). Whenever the current time is queried, the same millisecond time will be returned.

Parameters:

fixedMillis - the fixed millisecond time to use

Throws:

java.lang.SecurityException - if the application does not have sufficient security rights

setCurrentMillisOffset

public static final void setCurrentMillisOffset(long offsetMillis)
                                         throws java.lang.SecurityException

Sets the current time to return the system time plus an offset.

This method changes the behaviour of currentTimeMillis(). Whenever the current time is queried, System.currentTimeMillis() is used and then offset by adding the millisecond value specified here.

Parameters:

offsetMillis - the fixed millisecond time to use

Throws:

java.lang.SecurityException - if the application does not have sufficient security rights

setCurrentMillisProvider

public static final void setCurrentMillisProvider(DateTimeUtils.MillisProvider millisProvider)
                                           throws java.lang.SecurityException

Sets the provider of the current time to class specified.

This method changes the behaviour of currentTimeMillis(). Whenever the current time is queried, the specified class will be called.

Parameters:

millisProvider - the provider of the current time to use, not null

Throws:

java.lang.SecurityException - if the application does not have sufficient security rights

Since:

2.0

getInstantMillis

public static final long getInstantMillis(ReadableInstant instant)

Gets the millisecond instant from the specified instant object handling null.

If the instant object is null, the currentTimeMillis() will be returned. Otherwise, the millis from the object are returned.

Parameters:

instant - the instant to examine, null means now

Returns:

the time in milliseconds from 1970-01-01T00:00:00Z

getInstantChronology

public static final Chronology getInstantChronology(ReadableInstant instant)

Gets the chronology from the specified instant object handling null.

If the instant object is null, or the instant's chronology is null, ISOChronology.getInstance() will be returned. Otherwise, the chronology from the object is returned.

Parameters:

instant - the instant to examine, null means ISO in the default zone

Returns:

the chronology, never null

getIntervalChronology

public static final Chronology getIntervalChronology(ReadableInstant start,
                                                     ReadableInstant end)

Gets the chronology from the specified instant based interval handling null.

The chronology is obtained from the start if that is not null, or from the end if the start is null. The result is additionally checked, and if still null then ISOChronology.getInstance() will be returned.

Parameters:

start - the instant to examine and use as the primary source of the chronology

end - the instant to examine and use as the secondary source of the chronology

Returns:

the chronology, never null

getIntervalChronology

public static final Chronology getIntervalChronology(ReadableInterval interval)

Gets the chronology from the specified interval object handling null.

If the interval object is null, or the interval's chronology is null, ISOChronology.getInstance() will be returned. Otherwise, the chronology from the object is returned.

Parameters:

interval - the interval to examine, null means ISO in the default zone

Returns:

the chronology, never null

getReadableInterval

public static final ReadableInterval getReadableInterval(ReadableInterval interval)

Gets the interval handling null.

If the interval is null, an interval representing now to now in the ISOChronology will be returned. Otherwise, the interval specified is returned.

Parameters:

interval - the interval to use, null means now to now

Returns:

the interval, never null

Since:

1.1

getChronology

public static final Chronology getChronology(Chronology chrono)

Gets the chronology handling null.

If the chronology is null, ISOChronology.getInstance() will be returned. Otherwise, the chronology is returned.

Parameters:

chrono - the chronology to use, null means ISO in the default zone

Returns:

the chronology, never null

getZone

public static final DateTimeZone getZone(DateTimeZone zone)

Gets the zone handling null.

If the zone is null, DateTimeZone.getDefault() will be returned. Otherwise, the zone specified is returned.

Parameters:

zone - the time zone to use, null means the default zone

Returns:

the time zone, never null

getPeriodType

public static final PeriodType getPeriodType(PeriodType type)

Gets the period type handling null.

If the zone is null, PeriodType.standard() will be returned. Otherwise, the type specified is returned.

Parameters:

type - the time zone to use, null means the standard type

Returns:

the type to use, never null

getDurationMillis

public static final long getDurationMillis(ReadableDuration duration)

Gets the millisecond duration from the specified duration object handling null.

If the duration object is null, zero will be returned. Otherwise, the millis from the object are returned.

Parameters:

duration - the duration to examine, null means zero

Returns:

the duration in milliseconds

isContiguous

public static final boolean isContiguous(ReadablePartial partial)

Checks whether the partial is contiguous.

A partial is contiguous if one field starts where another ends.

For example LocalDate is contiguous because DayOfMonth has the same range (Month) as the unit of the next field (MonthOfYear), and MonthOfYear has the same range (Year) as the unit of the next field (Year).

Similarly, LocalTime is contiguous, as it consists of MillisOfSecond, SecondOfMinute, MinuteOfHour and HourOfDay (note how the names of each field 'join up').

However, a Year/HourOfDay partial is not contiguous because the range field Day is not equal to the next field Year. Similarly, a DayOfWeek/DayOfMonth partial is not contiguous because the range Month is not equal to the next field Day.

Parameters:

partial - the partial to check

Returns:

true if the partial is contiguous

Throws:

java.lang.IllegalArgumentException - if the partial is null

Since:

1.1

getDateFormatSymbols

public static final java.text.DateFormatSymbols getDateFormatSymbols(java.util.Locale locale)

Gets the DateFormatSymbols based on the given locale.

If JDK 6 or newer is being used, DateFormatSymbols.getInstance(locale) will be used in order to allow the use of locales defined as extensions. Otherwise, new DateFormatSymbols(locale) will be used. See JDK 6 DateFormatSymbols for further information.

Parameters:

locale - the Locale used to get the correct DateFormatSymbols

Returns:

the symbols

Since:

2.0

getDefaultTimeZoneNames

public static final java.util.Map<java.lang.String,DateTimeZone> getDefaultTimeZoneNames()

Gets the default map of time zone names.

This can be changed by setDefaultTimeZoneNames(java.util.Map<java.lang.String, org.joda.time.DateTimeZone>).

The default set of short time zone names is as follows:

• UT - UTC
• UTC - UTC
• GMT - UTC
• EST - America/New_York
• EDT - America/New_York
• CST - America/Chicago
• CDT - America/Chicago
• MST - America/Denver
• MDT - America/Denver
• PST - America/Los_Angeles
• PDT - America/Los_Angeles

Returns:

the unmodifiable map of abbreviations to zones, not null

Since:

2.2

setDefaultTimeZoneNames

public static final void setDefaultTimeZoneNames(java.util.Map<java.lang.String,DateTimeZone> names)

Sets the default map of time zone names.

The map is copied before storage.

Parameters:

names - the map of abbreviations to zones, not null

Since:

2.2

toJulianDay

public static final double toJulianDay(long epochMillis)

Calculates the astronomical Julian Day for an instant.

The Julian day is a well-known system of time measurement for scientific use by the astronomy community. It expresses the interval of time in days and fractions of a day since January 1, 4713 BC (Julian) Greenwich noon.

Each day starts at midday (not midnight) and time is expressed as a fraction. Thus the fraction 0.25 is 18:00. equal to one quarter of the day from midday to midday.

Note that this method has nothing to do with the day-of-year.

Parameters:

epochMillis - the epoch millis from 1970-01-01Z

Returns:

the astronomical Julian Day represented by the specified instant

Since:

2.2

toJulianDayNumber

public static final long toJulianDayNumber(long epochMillis)

Calculates the astronomical Julian Day Number for an instant.

The toJulianDay(long) method calculates the astronomical Julian Day with a fraction based on days starting at midday. This method calculates the variant where days start at midnight. JDN 0 is used for the date equivalent to Monday January 1, 4713 BC (Julian). Thus these days start 12 hours before those of the fractional Julian Day.

Note that this method has nothing to do with the day-of-year.

Parameters:

epochMillis - the epoch millis from 1970-01-01Z

Returns:

the astronomical Julian Day represented by the specified instant

Since:

2.2

fromJulianDay

public static final long fromJulianDay(double julianDay)

Creates a date-time from a Julian Day.

Returns the DateTime object equal to the specified Julian Day.

Parameters:

julianDay - the Julian Day

Returns:

the epoch millis from 1970-01-01Z

Since:

2.2