Examples of WeekFields

Localized definitions of the day-of-week, week-of-month and week-of-year fields.

A standard week is seven days long, but cultures have different definitions for some other aspects of a week. This class represents the definition of the week, for the purpose of providing {@link TemporalField} instances.

WeekFields provides three fields, {@link #dayOfWeek()}, {@link #weekOfMonth()}, and {@link #weekOfYear()}that provide access to the values from any {@link Temporal temporal object}.

The computations for day-of-week, week-of-month, and week-of-year are based on the {@link ChronoField#YEAR proleptic-year}, {@link ChronoField#MONTH_OF_YEAR month-of-year}, {@link ChronoField#DAY_OF_MONTH day-of-month}, and {@link ChronoField#DAY_OF_WEEK ISO day-of-week} which are based on the{@link ChronoField#EPOCH_DAY epoch-day} and the chronology.The values may not be aligned with the {@link ChronoField#YEAR_OF_ERA year-of-Era}depending on the Chronology.

A week is defined by:

The first day-of-week. For example, the ISO-8601 standard considers Monday to be the first day-of-week.
The minimal number of days in the first week. For example, the ISO-08601 standard counts the first week as needing at least 4 days.

Together these two values allow a year or month to be divided into weeks.

Week of Month

One field is used: week-of-month. The calculation ensures that weeks never overlap a month boundary. The month is divided into periods where each period starts on the defined first day-of-week. The earliest period is referred to as week 0 if it has less than the minimal number of days and week 1 if it has at least the minimal number of days.

Examples of WeekFields
Date	Day-of-week	First day: Monday Minimal days: 4	First day: Monday Minimal days: 5
2008-12-31	Wednesday	Week 5 of December 2008	Week 5 of December 2008
2009-01-01	Thursday	Week 1 of January 2009	Week 0 of January 2009
2009-01-04	Sunday	Week 1 of January 2009	Week 0 of January 2009
2009-01-05	Monday	Week 2 of January 2009	Week 1 of January 2009

Week of Year

One field is used: week-of-year. The calculation ensures that weeks never overlap a year boundary. The year is divided into periods where each period starts on the defined first day-of-week. The earliest period is referred to as week 0 if it has less than the minimal number of days and week 1 if it has at least the minimal number of days.

This class is immutable and thread-safe.