Package org.threeten.bp.chrono

Class JapaneseDate

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Comparable<ChronoLocalDate>, Temporal, TemporalAccessor, TemporalAdjuster
    public final class JapaneseDate
extends ChronoDateImpl<JapaneseDate>
implements java.io.Serializable
    A date in the Japanese Imperial calendar system.

    This date operates using the Japanese Imperial calendar. This calendar system is primarily used in Japan.

    The Japanese Imperial calendar system is the same as the ISO calendar system apart from the era-based year numbering. The proleptic-year is defined to be equal to the ISO proleptic-year.

    Japan introduced the Gregorian calendar starting with Meiji 6. Only Meiji and later eras are supported.

    For example, the Japanese year "Heisei 24" corresponds to ISO year "2012".
    Calling japaneseDate.get(YEAR_OF_ERA) will return 24.
    Calling japaneseDate.get(YEAR) will return 2012.
    Calling japaneseDate.get(ERA) will return 2, corresponding to JapaneseChEra.HEISEI.

    Specification for implementors

    This class is immutable and thread-safe.
    See Also:
    Serialized Form

    • Field Detail

      • serialVersionUID

        private static final long serialVersionUID
        Serialization version.
        See Also:
        Constant Field Values

      • MIN_DATE

        static final LocalDate MIN_DATE
        Minimum date.

      • isoDate

        private final LocalDate isoDate
        The underlying ISO local date.

      • era

        private transient JapaneseEra era
        The JapaneseEra of this date.

      • yearOfEra

        private transient int yearOfEra
        The Japanese imperial calendar year of this date.

    • Constructor Detail

      • JapaneseDate

        JapaneseDate​(LocalDate isoDate)
        Creates an instance from an ISO date.
        Parameters:
        isoDate - the standard local date, validated not null

      • JapaneseDate

        JapaneseDate​(JapaneseEra era,
             int year,
             LocalDate isoDate)
        Constructs a JapaneseDate. This constructor does NOT validate the given parameters, and era and year must agree with isoDate.
        Parameters:
        era - the era, validated not null
        year - the year-of-era, validated
        isoDate - the standard local date, validated not null

    • Method Detail

      • now

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

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

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

        Returns:
        the current date using the system clock and default time-zone, not null

      • now

        public static JapaneseDate now​(ZoneId zone)
        Obtains the current JapaneseDate from the system clock in the specified time-zone.

        This will query the system clock to obtain the current date. Specifying the time-zone avoids dependence on the default time-zone.

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

        Parameters:
        zone - the zone ID to use, not null
        Returns:
        the current date using the system clock, not null

      • now

        public static JapaneseDate now​(Clock clock)
        Obtains the current JapaneseDate from the specified clock.

        This will query the specified clock to obtain the current date - today. 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 date, not null
        Throws:
        DateTimeException - if the current date cannot be obtained

      • of

        public static JapaneseDate of​(JapaneseEra era,
                              int yearOfEra,
                              int month,
                              int dayOfMonth)
        Obtains a JapaneseDate representing a date in the Japanese calendar system from the era, year-of-era, month-of-year and day-of-month fields.

        This returns a JapaneseDate with the specified fields. The day must be valid for the year and month, otherwise an exception will be thrown.

        The Japanese month and day-of-month are the same as those in the ISO calendar system. They are not reset when the era changes. For example: 

          6th Jan Showa 64 = ISO 1989-01-06
  7th Jan Showa 64 = ISO 1989-01-07
  8th Jan Heisei 1 = ISO 1989-01-08
  9th Jan Heisei 1 = ISO 1989-01-09
        Parameters:
        era - the Japanese era, not null
        yearOfEra - the Japanese year-of-era
        month - the Japanese month-of-year, from 1 to 12
        dayOfMonth - the Japanese day-of-month, from 1 to 31
        Returns:
        the date in Japanese calendar system, not null
        Throws:
        DateTimeException - if the value of any field is out of range, or if the day-of-month is invalid for the month-year

      • ofYearDay

        static JapaneseDate ofYearDay​(JapaneseEra era,
                              int yearOfEra,
                              int dayOfYear)
        Obtains a JapaneseDate representing a date in the Japanese calendar system from the era, year-of-era and day-of-year fields.

        This returns a JapaneseDate with the specified fields. The day must be valid for the year, otherwise an exception will be thrown. The Japanese day-of-year is reset when the era changes.

        Parameters:
        era - the Japanese era, not null
        yearOfEra - the Japanese year-of-era
        dayOfYear - the Japanese day-of-year, from 1 to 31
        Returns:
        the date in Japanese calendar system, not null
        Throws:
        DateTimeException - if the value of any field is out of range, or if the day-of-year is invalid for the year

      • of

        public static JapaneseDate of​(int prolepticYear,
                              int month,
                              int dayOfMonth)
        Obtains a JapaneseDate representing a date in the Japanese calendar system from the proleptic-year, month-of-year and day-of-month fields.

        This returns a JapaneseDate with the specified fields. The day must be valid for the year and month, otherwise an exception will be thrown.

        The Japanese proleptic year, month and day-of-month are the same as those in the ISO calendar system. They are not reset when the era changes.

        Parameters:
        prolepticYear - the Japanese proleptic-year
        month - the Japanese month-of-year, from 1 to 12
        dayOfMonth - the Japanese day-of-month, from 1 to 31
        Returns:
        the date in Japanese calendar system, not null
        Throws:
        DateTimeException - if the value of any field is out of range, or if the day-of-month is invalid for the month-year

      • from

        public static JapaneseDate from​(TemporalAccessor temporal)
        Obtains a JapaneseDate from a temporal object.

        This obtains a date in the Japanese calendar system based on the specified temporal. A TemporalAccessor represents an arbitrary set of date and time information, which this factory converts to an instance of JapaneseDate.

        The conversion typically uses the EPOCH_DAY field, which is standardized across calendar systems.

        This method matches the signature of the functional interface TemporalQuery allowing it to be used as a query via method reference, JapaneseDate::from.

        Parameters:
        temporal - the temporal object to convert, not null
        Returns:
        the date in Japanese calendar system, not null
        Throws:
        DateTimeException - if unable to convert to a JapaneseDate

      • readObject

        private void readObject​(java.io.ObjectInputStream stream)
                 throws java.io.IOException,
                        java.lang.ClassNotFoundException
        Reconstitutes this object from a stream.
        Parameters:
        stream - object input stream
        Throws:
        java.io.IOException
        java.lang.ClassNotFoundException

      • getEra

        public JapaneseEra getEra()
        Description copied from class: ChronoLocalDate
        Gets the era, as defined by the chronology.

        The era is, conceptually, the largest division of the time-line. Most calendar systems have a single epoch dividing the time-line into two eras. However, some have multiple eras, such as one for the reign of each leader. The exact meaning is determined by the Chronology.

        All correctly implemented Era classes are singletons, thus it is valid code to write date.getEra() == SomeEra.NAME).

        Overrides:
        getEra in class ChronoLocalDate
        Returns:
        the chronology specific era constant applicable at this date, not null

      • lengthOfMonth

        public int lengthOfMonth()
        Description copied from class: ChronoLocalDate
        Returns the length of the month represented by this date, as defined by the calendar system.

        This returns the length of the month in days.

        Specified by:
        lengthOfMonth in class ChronoLocalDate
        Returns:
        the length of the month in days

      • lengthOfYear

        public int lengthOfYear()
        Description copied from class: ChronoLocalDate
        Returns the length of the year represented by this date, as defined by the calendar system.

        This returns the length of the year in days.

        The default implementation uses ChronoLocalDate.isLeapYear() and returns 365 or 366.

        Overrides:
        lengthOfYear in class ChronoLocalDate
        Returns:
        the length of the year in days

      • isSupported

        public boolean isSupported​(TemporalField field)
        Checks if the specified field is supported.

        This checks if this date can be queried for the specified field. If false, then calling the range and get methods will throw an exception.

        If the field is a ChronoField then the query is implemented here. The supported fields are:

        • DAY_OF_WEEK
        • DAY_OF_MONTH
        • DAY_OF_YEAR
        • EPOCH_DAY
        • MONTH_OF_YEAR
        • PROLEPTIC_MONTH
        • YEAR_OF_ERA
        • YEAR
        • ERA
        All other ChronoField instances will return false.

        If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.isSupportedBy(TemporalAccessor) passing this as the argument. Whether the field is supported is determined by the field.

        Specified by:
        isSupported in interface TemporalAccessor
        Overrides:
        isSupported in class ChronoLocalDate
        Parameters:
        field - the field to check, null returns false
        Returns:
        true if the field is supported on this date, false if not

      • range

        public ValueRange range​(TemporalField field)
        Description copied from interface: TemporalAccessor
        Gets the range of valid values for the specified field.

        All fields can be expressed as a long integer. This method returns an object that describes the valid range for that value. The value of this temporal object is used to enhance the accuracy of the returned range. If the date-time cannot return the range, because the field is unsupported or for some other reason, an exception will be thrown.

        Note that the result only describes the minimum and maximum valid values and it is important not to read too much into them. For example, there could be values within the range that are invalid for the field.

        Specification for implementors

        Implementations must check and handle all fields defined in ChronoField. If the field is supported, then the range of the field must be returned. If unsupported, then a DateTimeException must be thrown.

        If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.rangeRefinedBy(TemporalAccessorl) passing this as the argument.

        Implementations must not alter either this object.

        Specified by:
        range in interface TemporalAccessor
        Overrides:
        range in class DefaultInterfaceTemporalAccessor
        Parameters:
        field - the field to query the range for, not null
        Returns:
        the range of valid values for the field, not null

      • actualRange

        private ValueRange actualRange​(int calendarField)

      • getLong

        public long getLong​(TemporalField field)
        Description copied from interface: TemporalAccessor
        Gets the value of the specified field as a long.

        This queries the date-time for the value for the specified field. The returned value may be outside the valid range of values for the field. If the date-time cannot return the value, because the field is unsupported or for some other reason, an exception will be thrown.

        Specification for implementors

        Implementations must check and handle all fields defined in ChronoField. If the field is supported, then the value of the field must be returned. If unsupported, then a DateTimeException must be thrown.

        If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.getFrom(TemporalAccessor) passing this as the argument.

        Implementations must not alter either this object.

        Specified by:
        getLong in interface TemporalAccessor
        Parameters:
        field - the field to get, not null
        Returns:
        the value for the field

      • getDayOfYear

        private long getDayOfYear()

      • with

        public JapaneseDate with​(TemporalAdjuster adjuster)
        Description copied from interface: Temporal
        Returns an adjusted object of the same type as this object with the adjustment made.

        This adjusts this date-time according to the rules of the specified adjuster. A simple adjuster might simply set the one of the fields, such as the year field. A more complex adjuster might set the date to the last day of the month. A selection of common adjustments is provided in TemporalAdjusters. These include finding the "last day of the month" and "next Wednesday". The adjuster is responsible for handling special cases, such as the varying lengths of month and leap years.

        Some example code indicating how and why this method is used: 

          date = date.with(Month.JULY);        // most key classes implement TemporalAdjuster
  date = date.with(lastDayOfMonth());  // static import from TemporalAdjusters
  date = date.with(next(WEDNESDAY));   // static import from TemporalAdjusters and DayOfWeek

        Specification for implementors

        Implementations must not alter either this object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.
        Specified by:
        with in interface Temporal
        Overrides:
        with in class ChronoLocalDate
        Parameters:
        adjuster - the adjuster to use, not null
        Returns:
        an object of the same type with the specified adjustment made, not null

      • with

        public JapaneseDate with​(TemporalField field,
                         long newValue)
        Description copied from interface: Temporal
        Returns an object of the same type as this object with the specified field altered.

        This returns a new object based on this one with the value for the specified field changed. For example, on a LocalDate, this could be used to set the year, month or day-of-month. The returned object will have the same observable type as this object.

        In some cases, changing a field is not fully defined. For example, if the target object is a date representing the 31st January, then changing the month to February would be unclear. In cases like this, the field is responsible for resolving the result. Typically it will choose the previous valid date, which would be the last valid day of February in this example.

        Specification for implementors

        Implementations must check and handle all fields defined in ChronoField. If the field is supported, then the adjustment must be performed. If unsupported, then a DateTimeException must be thrown.

        If the field is not a ChronoField, then the result of this method is obtained by invoking TemporalField.adjustInto(Temporal, long) passing this as the first argument.

        Implementations must not alter either this object or the specified temporal object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.

        Specified by:
        with in interface Temporal
        Specified by:
        with in class ChronoLocalDate
        Parameters:
        field - the field to set in the result, not null
        newValue - the new value of the field in the result
        Returns:
        an object of the same type with the specified field set, not null

      • plus

        public JapaneseDate plus​(TemporalAmount amount)
        Description copied from interface: Temporal
        Returns an object of the same type as this object with an amount added.

        This adjusts this temporal, adding according to the rules of the specified amount. The amount is typically a Period but may be any other type implementing the TemporalAmount interface, such as Duration.

        Some example code indicating how and why this method is used: 

          date = date.plus(period);                  // add a Period instance
  date = date.plus(duration);                // add a Duration instance
  date = date.plus(workingDays(6));          // example user-written workingDays method

        Note that calling plus followed by minus is not guaranteed to return the same date-time.

        Specification for implementors

        Implementations must not alter either this object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.
        Specified by:
        plus in interface Temporal
        Overrides:
        plus in class ChronoLocalDate
        Parameters:
        amount - the amount to add, not null
        Returns:
        an object of the same type with the specified adjustment made, not null

      • plus

        public JapaneseDate plus​(long amountToAdd,
                         TemporalUnit unit)
        Description copied from interface: Temporal
        Returns an object of the same type as this object with the specified period added.

        This method returns a new object based on this one with the specified period added. For example, on a LocalDate, this could be used to add a number of years, months or days. The returned object will have the same observable type as this object.

        In some cases, changing a field is not fully defined. For example, if the target object is a date representing the 31st January, then adding one month would be unclear. In cases like this, the field is responsible for resolving the result. Typically it will choose the previous valid date, which would be the last valid day of February in this example.

        If the implementation represents a date-time that has boundaries, such as LocalTime, then the permitted units must include the boundary unit, but no multiples of the boundary unit. For example, LocalTime must accept DAYS but not WEEKS or MONTHS.

        Specification for implementors

        Implementations must check and handle all units defined in ChronoUnit. If the unit is supported, then the addition must be performed. If unsupported, then a DateTimeException must be thrown.

        If the unit is not a ChronoUnit, then the result of this method is obtained by invoking TemporalUnit.addTo(Temporal, long) passing this as the first argument.

        Implementations must not alter either this object or the specified temporal object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.

        Specified by:
        plus in interface Temporal
        Overrides:
        plus in class ChronoDateImpl<JapaneseDate>
        Parameters:
        amountToAdd - the amount of the specified unit to add, may be negative
        unit - the unit of the period to add, not null
        Returns:
        an object of the same type with the specified period added, not null

      • minus

        public JapaneseDate minus​(TemporalAmount amount)
        Description copied from interface: Temporal
        Returns an object of the same type as this object with an amount subtracted.

        This adjusts this temporal, subtracting according to the rules of the specified amount. The amount is typically a Period but may be any other type implementing the TemporalAmount interface, such as Duration.

        Some example code indicating how and why this method is used: 

          date = date.minus(period);                  // subtract a Period instance
  date = date.minus(duration);                // subtract a Duration instance
  date = date.minus(workingDays(6));          // example user-written workingDays method

        Note that calling plus followed by minus is not guaranteed to return the same date-time.

        Specification for implementors

        Implementations must not alter either this object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.
        Specified by:
        minus in interface Temporal
        Overrides:
        minus in class ChronoLocalDate
        Parameters:
        amount - the amount to subtract, not null
        Returns:
        an object of the same type with the specified adjustment made, not null

      • minus

        public JapaneseDate minus​(long amountToAdd,
                          TemporalUnit unit)
        Description copied from interface: Temporal
        Returns an object of the same type as this object with the specified period subtracted.

        This method returns a new object based on this one with the specified period subtracted. For example, on a LocalDate, this could be used to subtract a number of years, months or days. The returned object will have the same observable type as this object.

        In some cases, changing a field is not fully defined. For example, if the target object is a date representing the 31st March, then subtracting one month would be unclear. In cases like this, the field is responsible for resolving the result. Typically it will choose the previous valid date, which would be the last valid day of February in this example.

        If the implementation represents a date-time that has boundaries, such as LocalTime, then the permitted units must include the boundary unit, but no multiples of the boundary unit. For example, LocalTime must accept DAYS but not WEEKS or MONTHS.

        Specification for implementors

        Implementations must behave in a manor equivalent to the default method behavior.

        Implementations must not alter either this object or the specified temporal object. Instead, an adjusted copy of the original must be returned. This provides equivalent, safe behavior for immutable and mutable implementations.

        Specified by:
        minus in interface Temporal
        Overrides:
        minus in class ChronoLocalDate
        Parameters:
        amountToAdd - the amount of the specified unit to subtract, may be negative
        unit - the unit of the period to subtract, not null
        Returns:
        an object of the same type with the specified period subtracted, not null

      • withYear

        private JapaneseDate withYear​(JapaneseEra era,
                              int yearOfEra)
        Returns a copy of this date with the year altered.

        This method changes the year of the date. If the month-day is invalid for the year, then the previous valid day will be selected instead.

        This instance is immutable and unaffected by this method call.

        Parameters:
        era - the era to set in the result, not null
        yearOfEra - the year-of-era to set in the returned date
        Returns:
        a JapaneseDate based on this date with the requested year, never null
        Throws:
        DateTimeException - if year is invalid

      • withYear

        private JapaneseDate withYear​(int year)
        Returns a copy of this date with the year-of-era altered.

        This method changes the year-of-era of the date. If the month-day is invalid for the year, then the previous valid day will be selected instead.

        This instance is immutable and unaffected by this method call.

        Parameters:
        year - the year to set in the returned date
        Returns:
        a JapaneseDate based on this date with the requested year-of-era, never null
        Throws:
        DateTimeException - if year is invalid

      • plusYears

        JapaneseDate plusYears​(long years)
        Description copied from class: ChronoDateImpl
        Returns a copy of this date with the specified period in years added.

        This adds the specified period in years to the date. In some cases, adding years can cause the resulting date to become invalid. If this occurs, then other fields, typically the day-of-month, will be adjusted to ensure that the result is valid. Typically this will select the last valid day of the month.

        This instance is immutable and unaffected by this method call.

        Specified by:
        plusYears in class ChronoDateImpl<JapaneseDate>
        Parameters:
        years - the years to add, may be negative
        Returns:
        a date based on this one with the years added, not null

      • plusMonths

        JapaneseDate plusMonths​(long months)
        Description copied from class: ChronoDateImpl
        Returns a copy of this date with the specified period in months added.

        This adds the specified period in months to the date. In some cases, adding months can cause the resulting date to become invalid. If this occurs, then other fields, typically the day-of-month, will be adjusted to ensure that the result is valid. Typically this will select the last valid day of the month.

        This instance is immutable and unaffected by this method call.

        Specified by:
        plusMonths in class ChronoDateImpl<JapaneseDate>
        Parameters:
        months - the months to add, may be negative
        Returns:
        a date based on this one with the months added, not null

      • plusDays

        JapaneseDate plusDays​(long days)
        Description copied from class: ChronoDateImpl
        Returns a copy of this date with the specified number of days added.

        This adds the specified period in days to the date.

        This instance is immutable and unaffected by this method call.

        Specified by:
        plusDays in class ChronoDateImpl<JapaneseDate>
        Parameters:
        days - the days to add, may be negative
        Returns:
        a date based on this one with the days added, not null

      • atTime

        public final ChronoLocalDateTime<JapaneseDate> atTime​(LocalTime localTime)
        Description copied from class: ChronoLocalDate
        Combines this date with a time to create a ChronoLocalDateTime.

        This returns a ChronoLocalDateTime formed from this date at the specified time. All possible combinations of date and time are valid.

        Overrides:
        atTime in class ChronoDateImpl<JapaneseDate>
        Parameters:
        localTime - the local time to use, not null
        Returns:
        the local date-time formed from this date and the specified time, not null

      • until

        public ChronoPeriod until​(ChronoLocalDate endDate)
        Description copied from class: ChronoLocalDate
        Calculates the period between this date and another date as a ChronoPeriod.

        This calculates the period between two dates. All supplied chronologies calculate the period using years, months and days, however the ChronoPeriod API allows the period to be represented using other units.

        The start and end points are this and the specified date. The result will be negative if the end is before the start. The negative sign will be the same in each of year, month and day.

        The calculation is performed using the chronology of this date. If necessary, the input date will be converted to match.

        This instance is immutable and unaffected by this method call.

        Overrides:
        until in class ChronoDateImpl<JapaneseDate>
        Parameters:
        endDate - the end date, exclusive, which may be in any chronology, not null
        Returns:
        the period between this date and the end date, not null

      • toEpochDay

        public long toEpochDay()
        Description copied from class: ChronoLocalDate
        Converts this date to the Epoch Day.

        The Epoch Day count is a simple incrementing count of days where day 0 is 1970-01-01 (ISO). This definition is the same for all chronologies, enabling conversion.

        Overrides:
        toEpochDay in class ChronoLocalDate
        Returns:
        the Epoch Day equivalent to this date

      • equals

        public boolean equals​(java.lang.Object obj)
        Description copied from class: ChronoLocalDate
        Checks if this date is equal to another date, including the chronology.

        Compares this date with another ensuring that the date and chronology are the same.

        To compare the dates of two TemporalAccessor instances, including dates in two different chronologies, use ChronoField.EPOCH_DAY as a comparator.

        Overrides:
        equals in class ChronoLocalDate
        Parameters:
        obj - the object to check, null returns false
        Returns:
        true if this is equal to the other date

      • writeReplace

        private java.lang.Object writeReplace()

      • writeExternal

        void writeExternal​(java.io.DataOutput out)
            throws java.io.IOException
        Throws:
        java.io.IOException

      • readExternal

        static ChronoLocalDate readExternal​(java.io.DataInput in)
                             throws java.io.IOException
        Throws:
        java.io.IOException