org.threeten.bp
Class Year

java.lang.Object
  org.threeten.bp.jdk8.DefaultInterfaceTemporalAccessor
      org.threeten.bp.Year

All Implemented Interfaces:

Serializable, Comparable<Year>, Temporal, TemporalAccessor, TemporalAdjuster

public final class Year
extends DefaultInterfaceTemporalAccessor
implements Temporal, TemporalAdjuster, Comparable<Year>, Serializable

A year in the ISO-8601 calendar system, such as 2007.

Year is an immutable date-time object 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. 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 today's rules for leap years are applied for all time. For most applications written today, the ISO-8601 rules are entirely suitable. However, any application that makes use of historical dates, and requires them to be accurate will find the ISO-8601 approach unsuitable.

Specification for implementors

See Also:

Serialized Form

MIN_VALUE

public static final int MIN_VALUE

The minimum supported year, '-999,999,999'.

See Also:

Constant Field Values

MAX_VALUE

public static final int MAX_VALUE

The maximum supported year, '+999,999,999'.

See Also:

Constant Field Values

FROM

public static final TemporalQuery<Year> FROM

Simulate JDK 8 method reference Year::from.

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 and default time-zone, not null

now

public static Year now(ZoneId zone)

Obtains the current year from the system clock in the specified time-zone.

This will query the system clock to obtain the current year. 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 year using the system clock, not 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, not 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_VALUE to MAX_VALUE

Returns:

the year, not null

Throws:

DateTimeException - if the field is invalid

from

public static Year from(TemporalAccessor temporal)

Obtains an instance of Year from a temporal object.

A TemporalAccessor represents some form of date and time information. This factory converts the arbitrary temporal object to an instance of Year.

The conversion extracts the year field. The extraction is only permitted if the temporal object has an ISO chronology, or can be converted to a LocalDate.

This method matches the signature of the functional interface TemporalQuery allowing it to be used in queries via method reference, Year::from.

Parameters:

temporal - the temporal object to convert, not null

Returns:

the year, not null

Throws:

DateTimeException - if unable to convert to a Year

parse

public static Year parse(CharSequence text)

Obtains an instance of Year from a text string such as 2007.

The string must represent a valid year. Years outside the range 0000 to 9999 must be prefixed by the plus or minus symbol.

Parameters:

text - the text to parse such as "2007", not null

Returns:

the parsed year, not null

Throws:

DateTimeParseException - if the text cannot be parsed

parse

public static Year parse(CharSequence text,
                         DateTimeFormatter formatter)

Obtains an instance of Year from a text string using a specific formatter.

The text is parsed using the formatter, returning a year.

Parameters:

text - the text to parse, not null

formatter - the formatter to use, not null

Returns:

the parsed year, not null

Throws:

DateTimeParseException - if the text cannot be parsed

isLeap

public static boolean isLeap(long year)

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 ISO-8601 standard.

Parameters:

year - the year to check

Returns:

true if the year is leap, false otherwise

getValue

public int getValue()

Gets the year value.

The year returned by this method is proleptic as per get(YEAR).

Returns:

the year, MIN_VALUE to MAX_VALUE

isSupported

public boolean isSupported(TemporalField field)

Checks if the specified field is supported.

This checks if this year 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 will return valid values based on this date-time. The supported fields are:

• 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

Parameters:

field - the field to check, null returns false

Returns:

true if the field is supported on this year, false if not

isSupported

public boolean isSupported(TemporalUnit unit)

Description copied from interface: Temporal

Checks if the specified unit is supported.

This checks if the date-time can be queried for the specified unit. If false, then calling the plus and minus methods will throw an exception.

Specification for implementors

Implementations must check and handle all fields defined in ChronoUnit. If the field is supported, then true is returned, otherwise false

If the field is not a ChronoUnit, then the result of this method is obtained by invoking TemporalUnit.isSupportedBy(Temporal) passing this as the argument.

Implementations must not alter this object.

Specified by:

isSupported in interface Temporal

Parameters:

unit - the unit to check, null returns false

Returns:

true if this date-time can be queried for the unit, false if not

range

public ValueRange range(TemporalField field)

Gets the range of valid values for the specified field.

The range object expresses the minimum and maximum valid values for a field. This year is used to enhance the accuracy of the returned range. If it is not possible to return the range, because the field is not supported or for some other reason, an exception is thrown.

If the field is a ChronoField then the query is implemented here. The supported fields will return appropriate range instances. All other ChronoField instances will throw a DateTimeException.

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

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

Throws:

DateTimeException - if the range for the field cannot be obtained

get

public int get(TemporalField field)

Gets the value of the specified field from this year as an int.

This queries this year for the value for the specified field. The returned value will always be within the valid range of values for the field. If it is not possible to return the value, because the field is not supported or for some other reason, an exception is thrown.

If the field is a ChronoField then the query is implemented here. The supported fields will return valid values based on this year. All other ChronoField instances will throw a DateTimeException.

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. Whether the value can be obtained, and what the value represents, is determined by the field.

Specified by:

get in interface TemporalAccessor

Overrides:

get in class DefaultInterfaceTemporalAccessor

Parameters:

field - the field to get, not null

Returns:

the value for the field

Throws:

DateTimeException - if a value for the field cannot be obtained

ArithmeticException - if numeric overflow occurs

getLong

public long getLong(TemporalField field)

Gets the value of the specified field from this year as a long.

This queries this year for the value for the specified field. If it is not possible to return the value, because the field is not supported or for some other reason, an exception is thrown.

If the field is a ChronoField then the query is implemented here. The supported fields will return valid values based on this year. All other ChronoField instances will throw a DateTimeException.

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. Whether the value can be obtained, and what the value represents, is determined by the field.

Specified by:

getLong in interface TemporalAccessor

Parameters:

field - the field to get, not null

Returns:

the value for the field

Throws:

DateTimeException - if a value for the field cannot be obtained

ArithmeticException - if numeric overflow occurs

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 ISO-8601 standard.

Returns:

true if the year is leap, false otherwise

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

length

public int length()

Gets the length of this year in days.

Returns:

the length of this year in days, 365 or 366

with

public Year with(TemporalAdjuster adjuster)

Returns an adjusted copy of this year.

This returns a new Year, based on this one, with the year adjusted. The adjustment takes place using the specified adjuster strategy object. Read the documentation of the adjuster to understand what adjustment will be made.

The result of this method is obtained by invoking the TemporalAdjuster.adjustInto(Temporal) method on the specified adjuster passing this as the argument.

This instance is immutable and unaffected by this method call.

Specified by:

with in interface Temporal

Parameters:

adjuster - the adjuster to use, not null

Returns:

a Year based on this with the adjustment made, not null

Throws:

DateTimeException - if the adjustment cannot be made

ArithmeticException - if numeric overflow occurs

with

public Year with(TemporalField field,
                 long newValue)

Returns a copy of this year with the specified field set to a new value.

This returns a new Year, based on this one, with the value for the specified field changed. If it is not possible to set the value, because the field is not supported or for some other reason, an exception is thrown.

If the field is a ChronoField then the adjustment is implemented here. The supported fields behave as follows:

• YEAR_OF_ERA - Returns a Year with the specified year-of-era The era will be unchanged.
• YEAR - Returns a Year with the specified year. This completely replaces the date and is equivalent to of(int).
• ERA - Returns a Year with the specified era. The year-of-era will be unchanged.

In all cases, if the new value is outside the valid range of values for the field then a DateTimeException will be thrown.

All other ChronoField instances will throw a DateTimeException.

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 argument. In this case, the field determines whether and how to adjust the instant.

This instance is immutable and unaffected by this method call.

Specified by:

with in interface Temporal

Parameters:

field - the field to set in the result, not null

newValue - the new value of the field in the result

Returns:

a Year based on this with the specified field set, not null

Throws:

DateTimeException - if the field cannot be set

ArithmeticException - if numeric overflow occurs

plus

public Year plus(TemporalAmount amount)

Returns a copy of this year with the specified period added.

This method returns a new year based on this year with the specified period added. The adder is typically Period but may be any other type implementing the TemporalAmount interface. The calculation is delegated to the specified adjuster, which typically calls back to plus(long, TemporalUnit).

This instance is immutable and unaffected by this method call.

Specified by:

plus in interface Temporal

Parameters:

amount - the amount to add, not null

Returns:

a Year based on this year with the addition made, not null

Throws:

DateTimeException - if the addition cannot be made

ArithmeticException - if numeric overflow occurs

plus

public Year plus(long amountToAdd,
                 TemporalUnit unit)

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

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

Throws:

DateTimeException - if the unit cannot be added

ArithmeticException - if numeric overflow occurs

plusYears

public Year plusYears(long yearsToAdd)

Returns a copy of this year with the specified number of years added.

This instance is immutable and unaffected by this method call.

Parameters:

yearsToAdd - the years to add, may be negative

Returns:

a Year based on this year with the period added, not null

Throws:

DateTimeException - if the result exceeds the supported year range

minus

public Year minus(TemporalAmount amount)

Returns a copy of this year with the specified period subtracted.

This method returns a new year based on this year with the specified period subtracted. The subtractor is typically Period but may be any other type implementing the TemporalAmount interface. The calculation is delegated to the specified adjuster, which typically calls back to minus(long, TemporalUnit).

This instance is immutable and unaffected by this method call.

Specified by:

minus in interface Temporal

Parameters:

amount - the amount to subtract, not null

Returns:

a Year based on this year with the subtraction made, not null

Throws:

DateTimeException - if the subtraction cannot be made

ArithmeticException - if numeric overflow occurs

minus

public Year minus(long amountToSubtract,
                  TemporalUnit unit)

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

Parameters:

amountToSubtract - 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

Throws:

DateTimeException - if the unit cannot be subtracted

ArithmeticException - if numeric overflow occurs

minusYears

public Year minusYears(long yearsToSubtract)

Returns a copy of this year with the specified number of years subtracted.

This instance is immutable and unaffected by this method call.

Parameters:

yearsToSubtract - the years to subtract, may be negative

Returns:

a Year based on this year with the period subtracted, not null

Throws:

DateTimeException - if the result exceeds the supported year range

query

public <R> R query(TemporalQuery<R> query)

Queries this year using the specified query.

This queries this year using the specified query strategy object. The TemporalQuery object defines the logic to be used to obtain the result. Read the documentation of the query to understand what the result of this method will be.

The result of this method is obtained by invoking the TemporalQuery.queryFrom(TemporalAccessor) method on the specified query passing this as the argument.

Specified by:

query in interface TemporalAccessor

Overrides:

query in class DefaultInterfaceTemporalAccessor

Type Parameters:

R - the type of the result

Parameters:

query - the query to invoke, not null

Returns:

the query result, null may be returned (defined by the query)

Throws:

DateTimeException - if unable to query (defined by the query)

ArithmeticException - if numeric overflow occurs (defined by the query)

adjustInto

public Temporal adjustInto(Temporal temporal)

Adjusts the specified temporal object to have this year.

This returns a temporal object of the same observable type as the input with the year changed to be the same as this.

The adjustment is equivalent to using Temporal.with(TemporalField, long) passing ChronoField.YEAR as the field. If the specified temporal object does not use the ISO calendar system then a DateTimeException is thrown.

In most cases, it is clearer to reverse the calling pattern by using Temporal.with(TemporalAdjuster):

   // these two lines are equivalent, but the second approach is recommended
   temporal = thisYear.adjustInto(temporal);
   temporal = temporal.with(thisYear);
 

This instance is immutable and unaffected by this method call.

Specified by:

adjustInto in interface TemporalAdjuster

Parameters:

temporal - the target object to be adjusted, not null

Returns:

the adjusted object, not null

Throws:

DateTimeException - if unable to make the adjustment

ArithmeticException - if numeric overflow occurs

until

public long until(Temporal endExclusive,
                  TemporalUnit unit)

Calculates the period between this year and another year in terms of the specified unit.

This calculates the period between two years in terms of a single unit. The start and end points are this and the specified year. The result will be negative if the end is before the start. The Temporal passed to this method must be a Year. For example, the period in decades between two year can be calculated using startYear.until(endYear, DECADES).

The calculation returns a whole number, representing the number of complete units between the two years. For example, the period in decades between 2012 and 2031 will only be one decade as it is one year short of two decades.

This method operates in association with TemporalUnit.between(org.threeten.bp.temporal.Temporal, org.threeten.bp.temporal.Temporal). The result of this method is a long representing the amount of the specified unit. By contrast, the result of between is an object that can be used directly in addition/subtraction:

   long period = start.until(end, YEARS);   // this method
   dateTime.plus(YEARS.between(start, end));      // use in plus/minus
 

The calculation is implemented in this method for ChronoUnit. The units YEARS, DECADES, CENTURIES, MILLENNIA and ERAS are supported. Other ChronoUnit values will throw an exception.

If the unit is not a ChronoUnit, then the result of this method is obtained by invoking TemporalUnit.between(Temporal, Temporal) passing this as the first argument and the input temporal as the second argument.

This instance is immutable and unaffected by this method call.

Specified by:

until in interface Temporal

Parameters:

endExclusive - the end year, which is converted to a Year, not null

unit - the unit to measure the period in, not null

Returns:

the amount of the period between this year and the end year

Throws:

DateTimeException - if the period cannot be calculated

ArithmeticException - if numeric overflow occurs

atDay

public LocalDate atDay(int dayOfYear)

Combines this year with a day-of-year to create a LocalDate.

This returns a LocalDate formed from this year and the specified day-of-year.

The day-of-year value 366 is only valid in a leap year.

Parameters:

dayOfYear - the day-of-year to use, not null

Returns:

the local date formed from this year and the specified date of year, not null

Throws:

DateTimeException - if the day of year is zero or less, 366 or greater or equal to 366 and this is not a leap year

atMonth

public YearMonth atMonth(Month month)

Combines this year with a month to create a YearMonth.

This returns a YearMonth formed from this year and the specified month. All possible combinations of year and month are valid.

This method can be used as part of a chain to produce a date:

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

Parameters:

month - the month-of-year to use, not null

Returns:

the year-month formed from this year and the specified month, not null

atMonth

public YearMonth atMonth(int month)

Combines this year with a month to create a YearMonth.

This returns a YearMonth formed from this year and the specified month. All possible combinations of year and month are valid.

This method can be used as part of a chain to produce a date:

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

Parameters:

month - the month-of-year to use, from 1 (January) to 12 (December)

Returns:

the year-month formed from this year and the specified month, not null

Throws:

DateTimeException - if the month is invalid

atMonthDay

public LocalDate atMonthDay(MonthDay monthDay)

Combines this year with a month-day to create a LocalDate.

This returns a LocalDate formed from this year and the specified month-day.

A month-day of February 29th will be adjusted to February 28th in the resulting date if the year is not a leap year.

Parameters:

monthDay - the month-day to use, not null

Returns:

the local date formed from this year and the specified month-day, not null

compareTo

public int compareTo(Year other)

Compares this year to another year.

The comparison is based on the value of the year. It is "consistent with equals", as defined by Comparable.

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

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

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

equals

public boolean equals(Object obj)

Checks if this year is equal to another year.

The comparison is based on the time-line position of the years.

Overrides:

equals in class Object

Parameters:

obj - the object to check, null returns false

Returns:

true if this is equal to the other 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 this year as a String.

Overrides:

toString in class Object

Returns:

a string representation of this year, not null

format

public String format(DateTimeFormatter formatter)

Outputs this year as a String using the formatter.

This year will be passed to the formatter print method.

Parameters:

formatter - the formatter to use, not null

Returns:

the formatted year string, not null

Throws:

DateTimeException - if an error occurs during printing