net.time4j.engine

Class StartOfDay

java.lang.Object

net.time4j.engine.StartOfDay

public abstract class StartOfDay
extends Object

Defines the start of a given calendar day relative to midnight in seconds.

Since:

3.5/4.3

Author:

Meno Hochschild

Specification:

All subclasses must be immutable.

Field Summary

Fields

Modifier and Type	Field and Description
static StartOfDay	EVENING Start of calendar day at 18:00 on previous day.
static StartOfDay	MIDNIGHT Default start of calendar day at midnight.
static StartOfDay	MORNING Start of calendar day at 06:00 in the morning.

Method Summary

Modifier and Type	Method and Description
static <T extends UnixTime> StartOfDay	definedBy(ChronoFunction<CalendarDate,Optional<T>> event) Obtains the start of a calendar day as determined by given date function.
abstract int	getDeviation(CalendarDate calendarDay, TZID tzid) Yields the start of given calendar day relative to midnight in seconds.
static StartOfDay	ofFixedDeviation(int deviation) Obtains the start of a calendar day relative to midnight in fixed seconds.

Methods inherited from class java.lang.Object

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

Field Detail

MIDNIGHT

public static final StartOfDay MIDNIGHT

Default start of calendar day at midnight.

EVENING

public static final StartOfDay EVENING

Start of calendar day at 18:00 on previous day. Used in HebrewCalendar and HijriCalendar as rough approximation for sunset. However, most users should apply an astronomical definition.

See Also:

definedBy(ChronoFunction)

MORNING

public static final StartOfDay MORNING

Start of calendar day at 06:00 in the morning.

See Also:

EthiopianCalendar

Method Detail

ofFixedDeviation

public static StartOfDay ofFixedDeviation(int deviation)

Obtains the start of a calendar day relative to midnight in fixed seconds.

A negative deviation is explicitly allowed and refers to the previous calendar day.

Parameters:

deviation - the deviation of start of day relative to midnight in seconds on the local timeline

Returns:

start of day

Throws:

IllegalArgumentException - if the argument is out of range -43200 < deviation <= 43200

Since:

3.5/4.3

definedBy

public static <T extends UnixTime> StartOfDay definedBy(ChronoFunction<CalendarDate,Optional<T>> event)

Obtains the start of a calendar day as determined by given date function.

If the given function cannot determine a moment for a calendar day then an exception will be thrown. This method is most suitable for calendars whose days start on astronomical events like sunset. Example:

     HijriCalendar hijri = HijriCalendar.ofUmalqura(1436, 10, 2);
     SolarTime mekkaTime = SolarTime.ofLocation(21.4225, 39.826111);
     ZonalOffset saudiArabia = ZonalOffset.ofHours(OffsetSign.AHEAD_OF_UTC, 3);
     StartOfDay startOfDay = StartOfDay.definedBy(mekkaTime.sunset());

     // short after sunset (2015-07-17T19:05:40)
     System.out.println(
         hijri.atTime(19, 6).at(saudiArabia, startOfDay)); // 2015-07-17T19:06+03:00

     // short before sunset (2015-07-17T19:05:40)
     System.out.println(
         hijri.minus(CalendarDays.ONE).atTime(19, 5).at(saudiArabia, startOfDay)); // 2015-07-17T19:05+03:00
 

Type Parameters:

T - generic type parameter indicating the time of the event

Parameters:

event - function which yields the relevant moment for a given calendar day

Returns:

start of day

Since:

3.34/4.29

getDeviation

public abstract int getDeviation(CalendarDate calendarDay,
                                 TZID tzid)

Yields the start of given calendar day relative to midnight in seconds.

Parameters:

calendarDay - calendar day

tzid - timezone identifier, helps to resolve an UTC-event like sunset to a local time

Returns:

nominal deviation of start of day relative to midnight in seconds on the local timeline

Since:

5.0