Calendar.Builder (Java SE 15 & JDK 15)
Description: declaration: module: java.base, package: java.util, class: Calendar, class: Builder
Keywords: java.util.Calendar.Builder class

Module java.base
Package java.util

# Class Calendar.Builder

java.lang.Object
java.util.Calendar.Builder

Enclosing class:
  Calendar

    public static class Calendar.Builder
    extends Object

`Calendar.Builder` is used for creating a `Calendar` from various date-time parameters.

There are two ways to set a `Calendar` to a date-time value. One is to set the instant parameter to a millisecond offset from the Epoch. The other is to set individual field parameters, such as `YEAR`, to their desired values. These two ways can't be mixed. Trying to set both the instant and individual fields will cause an `IllegalStateException` to be thrown. However, it is permitted to override previous values of the instant or field parameters.

If no enough field parameters are given for determining date and/or time, calendar specific default values are used when building a `Calendar`. For example, if the `YEAR` value isn't given for the Gregorian calendar, 1970 will be used. If there are any conflicts among field parameters, the resolution rules are applied. Therefore, the order of field setting matters.

In addition to the date-time parameters, the locale, time zone, week definition, and leniency mode parameters can be set.

Examples

The following are sample usages. Sample code assumes that the `Calendar` constants are statically imported.

The following code produces a `Calendar` with date 2012-12-31 (Gregorian) because Monday is the first day of a week with the ISO 8601 compatible week parameters.

       Calendar cal = new Calendar.Builder().setCalendarType("iso8601")
                            .setWeekDate(2013, 1, MONDAY).build();

The following code produces a Japanese `Calendar` with date 1989-01-08 (Gregorian), assuming that the default `ERA` is Heisei that started on that day.

       Calendar cal = new Calendar.Builder().setCalendarType("japanese")
                            .setFields(YEAR, 1, DAY_OF_YEAR, 1).build();

Since:
  1.8
See Also:
  `Calendar.getInstance(TimeZone, Locale)`, `Calendar.fields`

- ## Constructor Summary

  Constructors
  Constructor | Description
  --- | ---
  `Builder()` | Constructs a `Calendar.Builder`.

- ## Method Summary

  Modifier and Type | Method | Description
  --- | --- | ---
  `Calendar` | `build()` | Returns a `Calendar` built from the parameters set by the setter methods.
  `Calendar.Builder` | `set​(int field, int value)` | Sets the `field` parameter to the given `value`.
  `Calendar.Builder` | `setCalendarType​(String type)` | Sets the calendar type parameter to the given `type`.
  `Calendar.Builder` | `setDate​(int year, int month, int dayOfMonth)` | Sets the date field parameters to the values given by `year`, `month`, and `dayOfMonth`.
  `Calendar.Builder` | `setFields​(int... fieldValuePairs)` | Sets field parameters to their values given by `fieldValuePairs` that are pairs of a field and its value.
  `Calendar.Builder` | `setInstant​(long instant)` | Sets the instant parameter to the given `instant` value that is a millisecond offset from the Epoch.
  `Calendar.Builder` | `setInstant​(Date instant)` | Sets the instant parameter to the `instant` value given by a `Date`.
  `Calendar.Builder` | `setLenient​(boolean lenient)` | Sets the lenient mode parameter to the value given by `lenient`.
  `Calendar.Builder` | `setLocale​(Locale locale)` | Sets the locale parameter to the given `locale`.
  `Calendar.Builder` | `setTimeOfDay​(int hourOfDay, int minute, int second)` | Sets the time of day field parameters to the values given by `hourOfDay`, `minute`, and `second`.
  `Calendar.Builder` | `setTimeOfDay​(int hourOfDay, int minute, int second, int millis)` | Sets the time of day field parameters to the values given by `hourOfDay`, `minute`, `second`, and `millis`.
  `Calendar.Builder` | `setTimeZone​(TimeZone zone)` | Sets the time zone parameter to the given `zone`.
  `Calendar.Builder` | `setWeekDate​(int weekYear, int weekOfYear, int dayOfWeek)` | Sets the week-based date parameters to the values with the given date specifiers - week year, week of year, and day of week.
  `Calendar.Builder` | `setWeekDefinition​(int firstDayOfWeek, int minimalDaysInFirstWeek)` | Sets the week definition parameters to the values given by `firstDayOfWeek` and `minimalDaysInFirstWeek` that are used to determine the first week of a year.

  ### Methods declared in class java.lang.Object

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

- ## Constructor Details

  - ### Builder

    public Builder()
    Constructs a `Calendar.Builder`.

- ## Method Details

  - ### setInstant

    public Calendar.Builder setInstant​(long instant)
    Sets the instant parameter to the given `instant` value that is a millisecond offset from the Epoch.
    Parameters:
      `instant` - a millisecond offset from the Epoch
    Returns:
      this `Calendar.Builder`
    Throws:
      `IllegalStateException` - if any of the field parameters have already been set
    See Also:
      `Calendar.setTime(Date)`, `Calendar.setTimeInMillis(long)`, `Calendar.time`

  - ### setInstant

    public Calendar.Builder setInstant​(Date instant)
    Sets the instant parameter to the `instant` value given by a `Date`. This method is equivalent to a call to `setInstant(instant.getTime())`.
    Parameters:
      `instant` - a `Date` representing a millisecond offset from the Epoch
    Returns:
      this `Calendar.Builder`
    Throws:
      `NullPointerException` - if `instant` is `null`
      `IllegalStateException` - if any of the field parameters have already been set
    See Also:
      `Calendar.setTime(Date)`, `Calendar.setTimeInMillis(long)`, `Calendar.time`

  - ### set

    public Calendar.Builder set​(int field, int value)
    Sets the `field` parameter to the given `value`. `field` is an index to the `Calendar.fields`, such as `DAY_OF_MONTH`. Field value validation is not performed in this method. Any out of range values are either normalized in lenient mode or detected as an invalid value in non-lenient mode when building a `Calendar`.
    Parameters:
      `field` - an index to the `Calendar` fields
      `value` - the field value
    Returns:
      this `Calendar.Builder`
    Throws:
      `IllegalArgumentException` - if `field` is invalid
      `IllegalStateException` - if the instant value has already been set, or if fields have been set too many (approximately `Integer.MAX_VALUE`) times.
    See Also:
      `Calendar.set(int, int)`

  - ### setFields

    public Calendar.Builder setFields​(int... fieldValuePairs)
    Sets field parameters to their values given by `fieldValuePairs` that are pairs of a field and its value. For example,

           setFields(Calendar.YEAR, 2013,
                     Calendar.MONTH, Calendar.DECEMBER,
                     Calendar.DAY_OF_MONTH, 23);

    is equivalent to the sequence of the following `set` calls:

           set(Calendar.YEAR, 2013)
           .set(Calendar.MONTH, Calendar.DECEMBER)
           .set(Calendar.DAY_OF_MONTH, 23);

    Parameters:
      `fieldValuePairs` - field-value pairs
    Returns:
      this `Calendar.Builder`
    Throws:
      `NullPointerException` - if `fieldValuePairs` is `null`
      `IllegalArgumentException` - if any of fields are invalid, or if `fieldValuePairs.length` is an odd number.
      `IllegalStateException` - if the instant value has been set, or if fields have been set too many (approximately `Integer.MAX_VALUE`) times.

  - ### setDate

    public Calendar.Builder setDate​(int year, int month, int dayOfMonth)
    Sets the date field parameters to the values given by `year`, `month`, and `dayOfMonth`. This method is equivalent to a call to:

           setFields(Calendar.YEAR, year,
                     Calendar.MONTH, month,
                     Calendar.DAY_OF_MONTH, dayOfMonth);

    Parameters:
      `year` - the `YEAR` value
      `month` - the `MONTH` value (the month numbering is 0-based).
      `dayOfMonth` - the `DAY_OF_MONTH` value
    Returns:
      this `Calendar.Builder`

  - ### setTimeOfDay

    public Calendar.Builder setTimeOfDay​(int hourOfDay, int minute, int second)
    Sets the time of day field parameters to the values given by `hourOfDay`, `minute`, and `second`. This method is equivalent to a call to:

           setTimeOfDay(hourOfDay, minute, second, 0);

    Parameters:
      `hourOfDay` - the `HOUR_OF_DAY` value (24-hour clock)
      `minute` - the `MINUTE` value
      `second` - the `SECOND` value
    Returns:
      this `Calendar.Builder`

  - ### setTimeOfDay

    public Calendar.Builder setTimeOfDay​(int hourOfDay, int minute, int second, int millis)
    Sets the time of day field parameters to the values given by `hourOfDay`, `minute`, `second`, and `millis`. This method is equivalent to a call to:

           setFields(Calendar.HOUR_OF_DAY, hourOfDay,
                     Calendar.MINUTE, minute,
                     Calendar.SECOND, second,
                     Calendar.MILLISECOND, millis);

    Parameters:
      `hourOfDay` - the `HOUR_OF_DAY` value (24-hour clock)
      `minute` - the `MINUTE` value
      `second` - the `SECOND` value
      `millis` - the `MILLISECOND` value
    Returns:
      this `Calendar.Builder`

  - ### setWeekDate

    public Calendar.Builder setWeekDate​(int weekYear, int weekOfYear, int dayOfWeek)
    Sets the week-based date parameters to the values with the given date specifiers - week year, week of year, and day of week.

    If the specified calendar doesn't support week dates, the `build` method will throw an `IllegalArgumentException`.

    Parameters:
      `weekYear` - the week year
      `weekOfYear` - the week number based on `weekYear`
      `dayOfWeek` - the day of week value: one of the constants for the `DAY_OF_WEEK` field: `SUNDAY`, ..., `SATURDAY`.
    Returns:
      this `Calendar.Builder`
    See Also:
      `Calendar.setWeekDate(int, int, int)`, `Calendar.isWeekDateSupported()`

  - ### setTimeZone

    public Calendar.Builder setTimeZone​(TimeZone zone)
    Sets the time zone parameter to the given `zone`. If no time zone parameter is given to this `Calendar.Builder`, the default {@code TimeZone} will be used in the `build` method.
    Parameters:
      `zone` - the `TimeZone`
    Returns:
      this `Calendar.Builder`
    Throws:
      `NullPointerException` - if `zone` is `null`
    See Also:
      `Calendar.setTimeZone(TimeZone)`

  - ### setLenient

    public Calendar.Builder setLenient​(boolean lenient)
    Sets the lenient mode parameter to the value given by `lenient`. If no lenient parameter is given to this `Calendar.Builder`, lenient mode will be used in the `build` method.
    Parameters:
      `lenient` - `true` for lenient mode; `false` for non-lenient mode
    Returns:
      this `Calendar.Builder`
    See Also:
      `Calendar.setLenient(boolean)`

  - ### setCalendarType

    public Calendar.Builder setCalendarType​(String type)
    Sets the calendar type parameter to the given `type`. The calendar type given by this method has precedence over any explicit or implicit calendar type given by the locale.

    In addition to the available calendar types returned by the `Calendar.getAvailableCalendarTypes` method, `"gregorian"` and `"iso8601"` as aliases of `"gregory"` can be used with this method.

    Parameters:
      `type` - the calendar type
    Returns:
      this `Calendar.Builder`
    Throws:
      `NullPointerException` - if `type` is `null`
      `IllegalArgumentException` - if `type` is unknown
      `IllegalStateException` - if another calendar type has already been set
    See Also:
      `Calendar.getCalendarType()`, `Calendar.getAvailableCalendarTypes()`

  - ### setLocale

    public Calendar.Builder setLocale​(Locale locale)
    Sets the locale parameter to the given `locale`. If no locale is given to this `Calendar.Builder`, the default {@code Locale} for `Locale.Category.FORMAT` will be used.

    If no calendar type is explicitly given by a call to the `setCalendarType` method, the `Locale` value is used to determine what type of `Calendar` to be built.

    If no week definition parameters are explicitly given by a call to the `setWeekDefinition` method, the `Locale`'s default values are used.

    Parameters:
      `locale` - the `Locale`
    Returns:
      this `Calendar.Builder`
    Throws:
      `NullPointerException` - if `locale` is `null`
    See Also:
      `Calendar.getInstance(Locale)`

  - ### setWeekDefinition

    public Calendar.Builder setWeekDefinition​(int firstDayOfWeek, int minimalDaysInFirstWeek)
    Sets the week definition parameters to the values given by `firstDayOfWeek` and `minimalDaysInFirstWeek` that are used to determine the first week of a year. The parameters given by this method have precedence over the default values given by the locale.
    Parameters:
      `firstDayOfWeek` - the first day of a week; one of `Calendar.SUNDAY` to `Calendar.SATURDAY`
      `minimalDaysInFirstWeek` - the minimal number of days in the first week (1..7)
    Returns:
      this `Calendar.Builder`
    Throws:
      `IllegalArgumentException` - if `firstDayOfWeek` or `minimalDaysInFirstWeek` is invalid
    See Also:
      `Calendar.getFirstDayOfWeek()`, `Calendar.getMinimalDaysInFirstWeek()`

  - ### build

    public Calendar build()
    Returns a `Calendar` built from the parameters set by the setter methods. The calendar type given by the `setCalendarType` method or the locale is used to determine what `Calendar` to be created. If no explicit calendar type is given, the locale's default calendar is created.

    If the calendar type is `"iso8601"`, the Gregorian change date of a `GregorianCalendar` is set to `Date(Long.MIN_VALUE)` to be the proleptic Gregorian calendar. Its week definition parameters are also set to be compatible with the ISO 8601 standard. Note that the `getCalendarType` method of a `GregorianCalendar` created with `"iso8601"` returns `"gregory"`.

    The default values are used for locale and time zone if these parameters haven't been given explicitly.

    If the locale contains the time zone with "tz" Unicode extension, and time zone hasn't been given explicitly, time zone in the locale is used.

    Any out of range field values are either normalized in lenient mode or detected as an invalid value in non-lenient mode.

    Returns:
      a `Calendar` built with parameters of this `Calendar.Builder`
    Throws:
      `IllegalArgumentException` - if the calendar type is unknown, or if any invalid field values are given in non-lenient mode, or if a week date is given for the calendar type that doesn't support week dates.
    See Also:
      `Calendar.getInstance(TimeZone, Locale)`, `Locale.getDefault(Locale.Category)`, `TimeZone.getDefault()`