Class Year

java.lang.Object
javax.time.calendar.Year
All Implemented Interfaces:
Serializable, Comparable<Year>, Calendrical, CalendricalMatcher, DateAdjuster
public final class Year extends Object implements Calendrical, Comparable<Year>, Serializable, DateAdjuster, CalendricalMatcher
A year in the ISO-8601 calendar system, such as 2007.

Year is an immutable calendrical that represents a year. Any field that can be derived from a year can be obtained.

Note that years in the ISO chronology only align with years in the Gregorian-Julian system for modern years. Parts of Russia did not switch to the modern Gregorian/ISO rules until 1920. As such, historical years must be treated with caution.

This class does not store or represent a month, day, time or time-zone. Thus, for example, the value "2007" can be stored in a Year.

Years represented by this class follow the ISO-8601 standard and use the proleptic numbering system. Year 1 is preceded by year 0, then by year -1.

The ISO-8601 calendar system is the modern civil calendar system used today in most of the world. It is equivalent to the proleptic Gregorian calendar system, in which todays's rules for leap years are applied for all time. For most applications written today, the ISO-8601 rules are entirely suitable. Any application that uses historical dates should consider using HistoricDate.

Year is immutable and thread-safe.

See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final int
    MAX_YEAR
    Constant for the maximum year on the proleptic ISO calendar system, 999,999,999.
    static final int
    MIN_YEAR
    Constant for the minimum year on the proleptic ISO calendar system, -999,999,999.
    private static final long
    serialVersionUID
    A serialization identifier for this class.
    private final int
    year
    The year being represented.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    private
    Year(int year)
    Constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    LocalDate
    adjustDate(LocalDate date)
    Adjusts a date to have the value of this year, returning a new date.
    LocalDate
    adjustDate(LocalDate date, DateResolver resolver)
    Adjusts a date to have the value of this year, using a resolver to handle the case when the day-of-month becomes invalid.
    LocalDate
    atDay(int dayOfYear)
    Returns a date formed from this year at the specified day-of-year.
    YearMonth
    atMonth(int monthOfYear)
    Returns a year-month formed from this year at the specified month.
    YearMonth
    atMonth(MonthOfYear monthOfYear)
    Returns a year-month formed from this year at the specified month.
    LocalDate
    atMonthDay(MonthDay monthDay)
    Returns a date formed from this year at the specified month-day.
    int
    compareTo(Year other)
    Compares this year to another year.
    boolean
    equals(Object other)
    Is this year equal to the specified year.
    <T> T
    get(CalendricalRule<T> rule)
    Gets the value of the specified calendrical rule.
    int
    getValue()
    Gets the year value.
    int
    hashCode()
    A hash code for this year.
    boolean
    isAfter(Year other)
    Is this year after the specified year.
    boolean
    isBefore(Year other)
    Is this year before the specified year.
    boolean
    isLeap()
    Checks if the year is a leap year, according to the ISO proleptic calendar system rules.
    boolean
    isValidMonthDay(MonthDay monthDay)
    Checks if the month-day is valid for this year.
    int
    lengthInDays()
    Gets the length of this year in days.
    boolean
    matchesCalendrical(Calendrical calendrical)
    Checks if the year extracted from the calendrical matches this.
    Year
    minus(PeriodProvider periodProvider)
    Returns a copy of this Year with the specified period subtracted.
    Year
    minusYears(long years)
    Returns a copy of this Year with the specified number of years subtracted.
    Year
    next()
    Returns the next year.
    Year
    nextLeap()
    Returns the next leap year after the current year.
    static Year
    now()
    Obtains the current year from the system clock in the default time-zone.
    static Year
    now(Clock clock)
    Obtains the current year from the specified clock.
    static Year
    of(int isoYear)
    Obtains an instance of Year.
    static Year
    of(Calendrical calendrical)
    Obtains an instance of Year from a calendrical.
    Year
    plus(PeriodProvider periodProvider)
    Returns a copy of this Year with the specified period added.
    Year
    plusYears(long years)
    Returns a copy of this Year with the specified number of years added.
    Year
    previous()
    Returns the previous year.
    Year
    previousLeap()
    Returns the previous leap year before the current year.
    static DateTimeFieldRule<Integer>
    rule()
    Gets the rule that defines how the year field operates.
    String
    toString()
    Outputs the string form of the year.

    Methods inherited from class Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • MIN_YEAR

      public static final int MIN_YEAR
      Constant for the minimum year on the proleptic ISO calendar system, -999,999,999.
      See Also:

    • MAX_YEAR

      public static final int MAX_YEAR
      Constant for the maximum year on the proleptic ISO calendar system, 999,999,999.
      See Also:

    • serialVersionUID

      private static final long serialVersionUID
      A serialization identifier for this class.
      See Also:

    • year

      private final int year
      The year being represented.

  • Constructor Details

    • Year

      private Year(int year)
      Constructor.
      Parameters:
      year - the year to represent

  • Method Details

    • rule

      public static DateTimeFieldRule<Integer> rule()
      Gets the rule that defines how the year field operates.

      The rule provides access to the minimum and maximum values, and a generic way to access values within a calendrical.

      Returns:
      the year rule, never null

    • now

      public static Year now()
      Obtains the current year from the system clock in the default time-zone.

      This will query the system clock in the default time-zone to obtain the current year.

      Using this method will prevent the ability to use an alternate clock for testing because the clock is hard-coded.

      Returns:
      the current year using the system clock, never null

    • now

      public static Year now(Clock clock)
      Obtains the current year from the specified clock.

      This will query the specified clock to obtain the current year. Using this method allows the use of an alternate clock for testing. The alternate clock may be introduced using dependency injection.

      Parameters:
      clock - the clock to use, not null
      Returns:
      the current year, never null

    • of

      public static Year of(int isoYear)
      Obtains an instance of Year.

      This method accepts a year value from the proleptic ISO calendar system.

      The year 2AD/CE is represented by 2.
      The year 1AD/CE is represented by 1.
      The year 1BC/BCE is represented by 0.
      The year 2BC/BCE is represented by -1.

      Parameters:
      isoYear - the ISO proleptic year to represent, from MIN_YEAR to MAX_YEAR
      Returns:
      the created Year, never null
      Throws:
      IllegalCalendarFieldValueException - if the field is invalid

    • of

      public static Year of(Calendrical calendrical)
      Obtains an instance of Year from a calendrical.

      This can be used extract the year value directly from any implementation of Calendrical, including those in other calendar systems.

      Parameters:
      calendrical - the calendrical to extract from, not null
      Returns:
      the Year instance, never null
      Throws:
      UnsupportedRuleException - if the year cannot be obtained

    • getValue

      public int getValue()
      Gets the year value.
      Returns:
      the year, from MIN_YEAR to MAX_YEAR

    • get

      public <T> T get(CalendricalRule<T> rule)
      Gets the value of the specified calendrical rule.

      This method queries the value of the specified calendrical rule. If the value cannot be returned for the rule from this instance then null will be returned.

      Specified by:
      get in interface Calendrical
      Parameters:
      rule - the rule to use, not null
      Returns:
      the value for the rule, null if the value cannot be returned

    • isLeap

      public boolean isLeap()
      Checks if the year is a leap year, according to the ISO proleptic calendar system rules.

      This method applies the current rules for leap years across the whole time-line. In general, a year is a leap year if it is divisible by four without remainder. However, years divisible by 100, are not leap years, with the exception of years divisible by 400 which are.

      For example, 1904 is a leap year it is divisible by 4. 1900 was not a leap year as it is divisible by 100, however 2000 was a leap year as it is divisible by 400.

      The calculation is proleptic - applying the same rules into the far future and far past. This is historically inaccurate, but is correct for the ISO8601 standard.

      Returns:
      true if the year is leap, false otherwise

    • next

      public Year next()
      Returns the next year.
      Returns:
      the next year, never null
      Throws:
      CalendricalException - if the maximum year is reached

    • nextLeap

      public Year nextLeap()
      Returns the next leap year after the current year. The definition of a leap year is specified in isLeap().
      Returns:
      the next leap year after this year, never null
      Throws:
      CalendricalException - if the maximum year is reached

    • previous

      public Year previous()
      Returns the previous year.
      Returns:
      the previous year, never null
      Throws:
      CalendricalException - if the maximum year is reached

    • previousLeap

      public Year previousLeap()
      Returns the previous leap year before the current year. The definition of a leap year is specified in isLeap().
      Returns:
      the previous leap year after this year, never null
      Throws:
      CalendricalException - if the minimum year is reached

    • plus

      public Year plus(PeriodProvider periodProvider)
      Returns a copy of this Year with the specified period added.

      This adds the specified period to this year, returning a new year. Before addition, the period is converted to a Period using Period.of(PeriodProvider). The calculation simply adds the amount of years from the specified period. ISO fields other than years are ignored.

      Note that no normalization is performed. Thus, adding 24 months has no effect. To take months into account, the period must be normalized by the caller.

      This instance is immutable and unaffected by this method call.

      Parameters:
      periodProvider - the period to add, not null
      Returns:
      a Year based on this year with the period added, never null
      Throws:
      CalendricalException - if the specified period cannot be converted to a Period
      ArithmeticException - if the result exceeds the supported year range

    • plusYears

      public Year plusYears(long years)
      Returns a copy of this Year with the specified number of years added.

      This instance is immutable and unaffected by this method call.

      Parameters:
      years - the years to add
      Returns:
      a Year based on this year with the period added, never null
      Throws:
      CalendricalException - if the result exceeds the supported year range

    • minus

      public Year minus(PeriodProvider periodProvider)
      Returns a copy of this Year with the specified period subtracted.

      This subtracts the specified period from this year, returning a new year. Before subtraction, the period is converted to a Period using Period.of(PeriodProvider). The calculation simply adds the amount of years from the specified period. ISO fields other than years are ignored.

      Note that no normalization is performed. Thus, subtracting 24 months has no effect. To take months into account, the period must be normalized by the caller.

      This instance is immutable and unaffected by this method call.

      Parameters:
      periodProvider - the period to subtract, not null
      Returns:
      a Year based on this year with the period subtracted, never null
      Throws:
      CalendricalException - if the specified period cannot be converted to a Period
      ArithmeticException - if the result exceeds the supported year range

    • minusYears

      public Year minusYears(long years)
      Returns a copy of this Year with the specified number of years subtracted.

      This instance is immutable and unaffected by this method call.

      Parameters:
      years - the years to subtract
      Returns:
      a Year based on this year with the period subtracted, never null
      Throws:
      CalendricalException - if the result exceeds the supported year range

    • matchesCalendrical

      public boolean matchesCalendrical(Calendrical calendrical)
      Checks if the year extracted from the calendrical matches this.

      This method implements the CalendricalMatcher interface. It is intended that applications use LocalDate.matches(CalendricalMatcher) rather than this method.

      Specified by:
      matchesCalendrical in interface CalendricalMatcher
      Parameters:
      calendrical - the calendrical to match, not null
      Returns:
      true if the calendrical matches, false otherwise

    • adjustDate

      public LocalDate adjustDate(LocalDate date)
      Adjusts a date to have the value of this year, returning a new date.

      This method implements the DateAdjuster interface. It is intended that, instead of calling this method directly, it is used from an instance of LocalDate: 

        date = date.with(year);

      This implementation handles the case where the date represents February 29 and this is not a leap year using the DateResolvers.previousValid() resolver.

      This instance is immutable and unaffected by this method call.

      Specified by:
      adjustDate in interface DateAdjuster
      Parameters:
      date - the date to be adjusted, not null
      Returns:
      the adjusted date, never null

    • adjustDate

      public LocalDate adjustDate(LocalDate date, DateResolver resolver)
      Adjusts a date to have the value of this year, using a resolver to handle the case when the day-of-month becomes invalid.

      This instance is immutable and unaffected by this method call.

      Parameters:
      date - the date to be adjusted, not null
      resolver - the date resolver to use if the day-of-month becomes invalid, not null
      Returns:
      the adjusted date, never null
      Throws:
      IllegalCalendarFieldValueException - if the date cannot be resolved using the resolver

    • lengthInDays

      public int lengthInDays()
      Gets the length of this year in days.
      Returns:
      the length of this year in days, 365 or 366

    • isValidMonthDay

      public boolean isValidMonthDay(MonthDay monthDay)
      Checks if the month-day is valid for this year.

      This method checks whether this year and the input month and day form a valid date.

      Parameters:
      monthDay - the month-day to validate, null returns false
      Returns:
      true if the month and day are valid for this year

    • atMonth

      public YearMonth atMonth(MonthOfYear monthOfYear)
      Returns a year-month formed from this year at the specified month.

      This method merges this and the specified month to form an instance of YearMonth. This method can be used as part of a chain to produce a date: 

      LocalDate date = year.atMonth(month).atDay(day);

      This instance is immutable and unaffected by this method call.

      Parameters:
      monthOfYear - the month-of-year to use, not null
      Returns:
      the year-month formed from this year and the specified month, never null

    • atMonth

      public YearMonth atMonth(int monthOfYear)
      Returns a year-month formed from this year at the specified month.

      This method merges this and the specified month to form an instance of YearMonth. This method can be used as part of a chain to produce a date: 

      LocalDate date = year.atMonth(month).atDay(day);

      This instance is immutable and unaffected by this method call.

      Parameters:
      monthOfYear - the month-of-year to use, from 1 (January) to 12 (December)
      Returns:
      the year-month formed from this year and the specified month, never null

    • atMonthDay

      public LocalDate atMonthDay(MonthDay monthDay)
      Returns a date formed from this year at the specified month-day.

      This merges the two objects - this and the specified day - to form an instance of LocalDate. 

      LocalDate date = year.atMonthDay(monthDay);

      This instance is immutable and unaffected by this method call.

      Parameters:
      monthDay - the month-day to use, not null
      Returns:
      the local date formed from this year and the specified month-day, never null
      Throws:
      InvalidCalendarFieldException - if the month-day is February 29th and this is not a leap year

    • atDay

      public LocalDate atDay(int dayOfYear)
      Returns a date formed from this year at the specified day-of-year.

      This merges the two objects - this and the specified day - to form an instance of LocalDate. 

      LocalDate date = year.atDay(dayOfYear);

      This instance is immutable and unaffected by this method call.

      Parameters:
      dayOfYear - the day-of-year to use, not null
      Returns:
      the local date formed from this year and the specified date of year, never null
      Throws:
      InvalidCalendarFieldException - if the day of year is 366 and this is not a leap year

    • compareTo

      public int compareTo(Year other)
      Compares this year to another year.
      Specified by:
      compareTo in interface Comparable<Year>
      Parameters:
      other - the other year to compare to, not null
      Returns:
      the comparator value, negative if less, positive if greater
      Throws:
      NullPointerException - if other is null

    • isAfter

      public boolean isAfter(Year other)
      Is this year after the specified year.
      Parameters:
      other - the other year to compare to, not null
      Returns:
      true if this is after the specified year
      Throws:
      NullPointerException - if other is null

    • isBefore

      public boolean isBefore(Year other)
      Is this year before the specified year.
      Parameters:
      other - the other year to compare to, not null
      Returns:
      true if this point is before the specified year
      Throws:
      NullPointerException - if other is null

    • equals

      public boolean equals(Object other)
      Is this year equal to the specified year.
      Overrides:
      equals in class Object
      Parameters:
      other - the other year to compare to, null returns false
      Returns:
      true if this point is equal to the specified year

    • hashCode

      public int hashCode()
      A hash code for this year.
      Overrides:
      hashCode in class Object
      Returns:
      a suitable hash code

    • toString

      public String toString()
      Outputs the string form of the year.
      Overrides:
      toString in class Object
      Returns:
      the string form of the year