net.time4j.engine

Interface StartOfDay

public interface StartOfDay

Defines the start of a calendar day.

Background is the fact that some calendar systems start calendar days at another time than midnight. For example the islamic calendars start the day at sunset on previous day.

Author:

Meno Hochschild

Field Summary

Fields

Modifier and Type	Field and Description
static StartOfDay	MIDNIGHT The calendar day starts at midnight.

Method Summary

Methods

Modifier and Type	Method and Description
int	getShift(long epochDays) Queries the start time of given calendar day in seconds relative to midnight (UTC).
boolean	isFixed() Queries if the start of a calendar day always happens at the same time.

Field Detail

MIDNIGHT

static final StartOfDay MIDNIGHT

The calendar day starts at midnight.

This setting is valid for all ISO-8601-systems by default. An exception are certain timezones where days might start later than midnight due to daylight-saving-change, for example in Brazil.

Method Detail

getShift

int getShift(long epochDays)

Queries the start time of given calendar day in seconds relative to midnight (UTC).

Example: In Israel the legal hebrew calendar day starts at 6 PM on previous day, so the shift is negative with the value -6 * 60 * 60. In a religious context the concrete time of sunset is important so the given argument can be used to calculate the season-dependent position of the sun.

Parameters:

epochDays - count of days relative to UTC epoch [1972-01-01]

Returns:

shift in seconds relative to midnight (positive or negative)

isFixed

boolean isFixed()

Queries if the start of a calendar day always happens at the same time.

Returns:

true if the day always starts at the same wall time else false