Added in API level 26

Period

class Period : ChronoPeriod, Serializable
kotlin.Any
   ↳ java.time.Period

A date-based amount of time in the ISO-8601 calendar system, such as '2 years, 3 months and 4 days'.

This class models a quantity or amount of time in terms of years, months and days. See Duration for the time-based equivalent to this class.

Durations and periods differ in their treatment of daylight savings time when added to ZonedDateTime. A Duration will add an exact number of seconds, thus a duration of one day is always exactly 24 hours. By contrast, a Period will add a conceptual day, trying to maintain the local time.

For example, consider adding a period of one day and a duration of one day to 18:00 on the evening before a daylight savings gap. The Period will add the conceptual day and result in a ZonedDateTime at 18:00 the following day. By contrast, the Duration will add exactly 24 hours, resulting in a ZonedDateTime at 19:00 the following day (assuming a one hour DST gap).

The supported units of a period are YEARS, MONTHS and DAYS. All three fields are always present, but may be set to zero.

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.

The period is modeled as a directed amount of time, meaning that individual parts of the period may be negative.

Summary

Public methods
Temporal!
addTo(temporal: Temporal!)

Adds this period to the specified temporal object.

static Period!
between(startDateInclusive: LocalDate!, endDateExclusive: LocalDate!)

Obtains a Period consisting of the number of years, months, and days between two dates.

Boolean
equals(other: Any?)

Checks if this period is equal to another period.

static Period!
from(amount: TemporalAmount!)

Obtains an instance of Period from a temporal amount.

Long
get(unit: TemporalUnit!)

Gets the value of the requested unit.

IsoChronology!

Gets the chronology of this period, which is the ISO calendar system.

Int

Gets the amount of days of this period.

Int

Gets the amount of months of this period.

MutableList<TemporalUnit!>!

Gets the set of units supported by this period.

Int

Gets the amount of years of this period.

Int

A hash code for this period.

Boolean

Checks if any of the three units of this period are negative.

Boolean

Checks if all three units of this period are zero.

Period!
minus(amountToSubtract: TemporalAmount!)

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

Period!
minusDays(daysToSubtract: Long)

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

Period!
minusMonths(monthsToSubtract: Long)

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

Period!
minusYears(yearsToSubtract: Long)

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

Period!
multipliedBy(scalar: Int)

Returns a new instance with each element in this period multiplied by the specified scalar.

Period!

Returns a new instance with each amount in this period negated.

Period!

Returns a copy of this period with the years and months normalized.

static Period!
of(years: Int, months: Int, days: Int)

Obtains a Period representing a number of years, months and days.

static Period!
ofDays(days: Int)

Obtains a Period representing a number of days.

static Period!
ofMonths(months: Int)

Obtains a Period representing a number of months.

static Period!
ofWeeks(weeks: Int)

Obtains a Period representing a number of weeks.

static Period!
ofYears(years: Int)

Obtains a Period representing a number of years.

static Period!

Obtains a Period from a text string such as PnYnMnD.

Period!
plus(amountToAdd: TemporalAmount!)

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

Period!
plusDays(daysToAdd: Long)

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

Period!
plusMonths(monthsToAdd: Long)

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

Period!
plusYears(yearsToAdd: Long)

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

Temporal!
subtractFrom(temporal: Temporal!)

Subtracts this period from the specified temporal object.

String

Outputs this period as a String, such as P6Y3M1D.

Long

Gets the total number of months in this period.

Period!
withDays(days: Int)

Returns a copy of this period with the specified amount of days.

Period!
withMonths(months: Int)

Returns a copy of this period with the specified amount of months.

Period!
withYears(years: Int)

Returns a copy of this period with the specified amount of years.

Properties
static Period!

A constant for a period of zero.

Public methods

addTo

Added in API level 26
fun addTo(temporal: Temporal!): Temporal!

Adds this period to the specified temporal object.

This returns a temporal object of the same observable type as the input with this period added. If the temporal has a chronology, it must be the ISO chronology.

In most cases, it is clearer to reverse the calling pattern by using Temporal#plus(TemporalAmount).

// these two lines are equivalent, but the second approach is recommended
    dateTime = thisPeriod.addTo(dateTime);
    dateTime = dateTime.plus(thisPeriod);
  

The calculation operates as follows. First, the chronology of the temporal is checked to ensure it is ISO chronology or null. Second, if the months are zero, the years are added if non-zero, otherwise the combination of years and months is added if non-zero. Finally, any days are added.

This approach ensures that a partial period can be added to a partial date. For example, a period of years and/or months can be added to a YearMonth, but a period including days cannot. The approach also adds years and months together when necessary, which ensures correct behaviour at the end of the month.

This instance is immutable and unaffected by this method call.

Parameters
temporal Temporal!: the temporal object to adjust, not null
Return
Temporal! an object of the same type with the adjustment made, not null
Exceptions
java.time.DateTimeException if unable to add
java.lang.ArithmeticException if numeric overflow occurs

between

Added in API level 26
static fun between(
    startDateInclusive: LocalDate!,
    endDateExclusive: LocalDate!
): Period!

Obtains a Period consisting of the number of years, months, and days between two dates.

The start date is included, but the end date is not. The period is calculated by removing complete months, then calculating the remaining number of days, adjusting to ensure that both have the same sign. The number of months is then split into years and months based on a 12 month year. A month is considered if the end day-of-month is greater than or equal to the start day-of-month. For example, from 2010-01-15 to 2011-03-18 is one year, two months and three days.

The result of this method can be a negative period if the end is before the start. The negative sign will be the same in each of year, month and day.

Parameters
startDateInclusive LocalDate!: the start date, inclusive, not null
endDateExclusive LocalDate!: the end date, exclusive, not null
Return
Period! the period between this date and the end date, not null

equals

Added in API level 26
fun equals(other: Any?): Boolean

Checks if this period is equal to another period.

The comparison is based on the type Period and each of the three amounts. To be equal, the years, months and days units must be individually equal. Note that this means that a period of "15 Months" is not equal to a period of "1 Year and 3 Months".

Parameters
obj the object to check, null returns false
Return
Boolean true if this is equal to the other period

from

Added in API level 26
static fun from(amount: TemporalAmount!): Period!

Obtains an instance of Period from a temporal amount.

This obtains a period based on the specified amount. A TemporalAmount represents an amount of time, which may be date-based or time-based, which this factory extracts to a Period.

The conversion loops around the set of units from the amount and uses the YEARS, MONTHS and DAYS units to create a period. If any other units are found then an exception is thrown.

If the amount is a ChronoPeriod then it must use the ISO chronology.

Parameters
amount TemporalAmount!: the temporal amount to convert, not null
Return
Period! the equivalent period, not null
Exceptions
java.time.DateTimeException if unable to convert to a Period
java.lang.ArithmeticException if the amount of years, months or days exceeds an int

get

Added in API level 26
fun get(unit: TemporalUnit!): Long

Gets the value of the requested unit.

This returns a value for each of the three supported units, YEARS, MONTHS and DAYS. All other units throw an exception.

Parameters
unit TemporalUnit!: the TemporalUnit for which to return the value
Return
Long the long value of the unit
Exceptions
java.time.DateTimeException if the unit is not supported
java.time.temporal.UnsupportedTemporalTypeException if the unit is not supported

getChronology

Added in API level 26
fun getChronology(): IsoChronology!

Gets the chronology of this period, which is the ISO calendar system.

The Chronology represents the calendar system in use. 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.

Return
IsoChronology! the ISO chronology, not null

getDays

Added in API level 26
fun getDays(): Int

Gets the amount of days of this period.

This returns the days unit.

Return
Int the amount of days of this period, may be negative

getMonths

Added in API level 26
fun getMonths(): Int

Gets the amount of months of this period.

This returns the months unit.

The months unit is not automatically normalized with the years unit. This means that a period of "15 months" is different to a period of "1 year and 3 months".

Return
Int the amount of months of this period, may be negative

getUnits

Added in API level 26
fun getUnits(): MutableList<TemporalUnit!>!

Gets the set of units supported by this period.

The supported units are YEARS, MONTHS and DAYS. They are returned in the order years, months, days.

This set can be used in conjunction with #get(java.time.temporal.TemporalUnit) to access the entire state of the period.

Return
MutableList<TemporalUnit!>! a list containing the years, months and days units, not null

getYears

Added in API level 26
fun getYears(): Int

Gets the amount of years of this period.

This returns the years unit.

The months unit is not automatically normalized with the years unit. This means that a period of "15 months" is different to a period of "1 year and 3 months".

Return
Int the amount of years of this period, may be negative

hashCode

Added in API level 26
fun hashCode(): Int

A hash code for this period.

Return
Int a suitable hash code

isNegative

Added in API level 26
fun isNegative(): Boolean

Checks if any of the three units of this period are negative.

This checks whether the years, months or days units are less than zero.

Return
Boolean true if any unit of this period is negative

isZero

Added in API level 26
fun isZero(): Boolean

Checks if all three units of this period are zero.

A zero period has the value zero for the years, months and days units.

Return
Boolean true if this period is zero-length

minus

Added in API level 26
fun minus(amountToSubtract: TemporalAmount!): Period!

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

This operates separately on the years, months and days. No normalization is performed.

For example, "1 year, 6 months and 3 days" minus "2 years, 2 months and 2 days" returns "-1 years, 4 months and 1 day".

The specified amount is typically an instance of Period. Other types are interpreted using Period#from(TemporalAmount).

This instance is immutable and unaffected by this method call.

Parameters
amountToSubtract TemporalAmount!: the amount to subtract, not null
Return
Period! a Period based on this period with the requested period subtracted, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs
java.time.DateTimeException if the specified amount has a non-ISO chronology or contains an invalid unit

minusDays

Added in API level 26
fun minusDays(daysToSubtract: Long): Period!

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

This subtracts the amount from the days unit in a copy of this period. The years and months units are unaffected. For example, "1 year, 6 months and 3 days" minus 2 days returns "1 year, 6 months and 1 day".

This instance is immutable and unaffected by this method call.

Parameters
daysToSubtract Long: the months to subtract, positive or negative
Return
Period! a Period based on this period with the specified days subtracted, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs

minusMonths

Added in API level 26
fun minusMonths(monthsToSubtract: Long): Period!

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

This subtracts the amount from the months unit in a copy of this period. The years and days units are unaffected. For example, "1 year, 6 months and 3 days" minus 2 months returns "1 year, 4 months and 3 days".

This instance is immutable and unaffected by this method call.

Parameters
monthsToSubtract Long: the years to subtract, positive or negative
Return
Period! a Period based on this period with the specified months subtracted, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs

minusYears

Added in API level 26
fun minusYears(yearsToSubtract: Long): Period!

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

This subtracts the amount from the years unit in a copy of this period. The months and days units are unaffected. For example, "1 year, 6 months and 3 days" minus 2 years returns "-1 years, 6 months and 3 days".

This instance is immutable and unaffected by this method call.

Parameters
yearsToSubtract Long: the years to subtract, positive or negative
Return
Period! a Period based on this period with the specified years subtracted, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs

multipliedBy

Added in API level 26
fun multipliedBy(scalar: Int): Period!

Returns a new instance with each element in this period multiplied by the specified scalar.

This returns a period with each of the years, months and days units individually multiplied. For example, a period of "2 years, -3 months and 4 days" multiplied by 3 will return "6 years, -9 months and 12 days". No normalization is performed.

Parameters
scalar Int: the scalar to multiply by, not null
Return
Period! a Period based on this period with the amounts multiplied by the scalar, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs

negated

Added in API level 26
fun negated(): Period!

Returns a new instance with each amount in this period negated.

This returns a period with each of the years, months and days units individually negated. For example, a period of "2 years, -3 months and 4 days" will be negated to "-2 years, 3 months and -4 days". No normalization is performed.

Return
Period! a Period based on this period with the amounts negated, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs, which only happens if one of the units has the value Integer.MIN_VALUE

normalized

Added in API level 26
fun normalized(): Period!

Returns a copy of this period with the years and months normalized.

This normalizes the years and months units, leaving the days unit unchanged. The months unit is adjusted to have an absolute value less than 12, with the years unit being adjusted to compensate. For example, a period of "1 Year and 15 months" will be normalized to "2 years and 3 months".

The sign of the years and months units will be the same after normalization. For example, a period of "1 year and -25 months" will be normalized to "-1 year and -1 month".

This instance is immutable and unaffected by this method call.

Return
Period! a Period based on this period with excess months normalized to years, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs

of

Added in API level 26
static fun of(
    years: Int,
    months: Int,
    days: Int
): Period!

Obtains a Period representing a number of years, months and days.

This creates an instance based on years, months and days.

Parameters
years Int: the amount of years, may be negative
months Int: the amount of months, may be negative
days Int: the amount of days, may be negative
Return
Period! the period of years, months and days, not null

ofDays

Added in API level 26
static fun ofDays(days: Int): Period!

Obtains a Period representing a number of days.

The resulting period will have the specified days. The years and months units will be zero.

Parameters
days Int: the number of days, positive or negative
Return
Period! the period of days, not null

ofMonths

Added in API level 26
static fun ofMonths(months: Int): Period!

Obtains a Period representing a number of months.

The resulting period will have the specified months. The years and days units will be zero.

Parameters
months Int: the number of months, positive or negative
Return
Period! the period of months, not null

ofWeeks

Added in API level 26
static fun ofWeeks(weeks: Int): Period!

Obtains a Period representing a number of weeks.

The resulting period will be day-based, with the amount of days equal to the number of weeks multiplied by 7. The years and months units will be zero.

Parameters
weeks Int: the number of weeks, positive or negative
Return
Period! the period, with the input weeks converted to days, not null

ofYears

Added in API level 26
static fun ofYears(years: Int): Period!

Obtains a Period representing a number of years.

The resulting period will have the specified years. The months and days units will be zero.

Parameters
years Int: the number of years, positive or negative
Return
Period! the period of years, not null

parse

Added in API level 26
static fun parse(text: CharSequence!): Period!

Obtains a Period from a text string such as PnYnMnD.

This will parse the string produced by toString() which is based on the ISO-8601 period formats PnYnMnD and PnW.

The string starts with an optional sign, denoted by the ASCII negative or positive symbol. If negative, the whole period is negated. The ASCII letter "P" is next in upper or lower case. There are then four sections, each consisting of a number and a suffix. At least one of the four sections must be present. The sections have suffixes in ASCII of "Y", "M", "W" and "D" for years, months, weeks and days, accepted in upper or lower case. The suffixes must occur in order. The number part of each section must consist of ASCII digits. The number may be prefixed by the ASCII negative or positive symbol. The number must parse to an int.

The leading plus/minus sign, and negative values for other units are not part of the ISO-8601 standard. In addition, ISO-8601 does not permit mixing between the PnYnMnD and PnW formats. Any week-based input is multiplied by 7 and treated as a number of days.

For example, the following are valid inputs:

"P2Y"             -- Period.ofYears(2)
    "P3M"             -- Period.ofMonths(3)
    "P4W"             -- Period.ofWeeks(4)
    "P5D"             -- Period.ofDays(5)
    "P1Y2M3D"         -- Period.of(1, 2, 3)
    "P1Y2M3W4D"       -- Period.of(1, 2, 25)
    "P-1Y2M"          -- Period.of(-1, 2, 0)
    "-P1Y2M"          -- Period.of(-1, -2, 0)
  
Parameters
text CharSequence!: the text to parse, not null
Return
Period! the parsed period, not null
Exceptions
java.time.format.DateTimeParseException if the text cannot be parsed to a period

plus

Added in API level 26
fun plus(amountToAdd: TemporalAmount!): Period!

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

This operates separately on the years, months and days. No normalization is performed.

For example, "1 year, 6 months and 3 days" plus "2 years, 2 months and 2 days" returns "3 years, 8 months and 5 days".

The specified amount is typically an instance of Period. Other types are interpreted using Period#from(TemporalAmount).

This instance is immutable and unaffected by this method call.

Parameters
amountToAdd TemporalAmount!: the amount to add, not null
Return
Period! a Period based on this period with the requested period added, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs
java.time.DateTimeException if the specified amount has a non-ISO chronology or contains an invalid unit

plusDays

Added in API level 26
fun plusDays(daysToAdd: Long): Period!

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

This adds the amount to the days unit in a copy of this period. The years and months units are unaffected. For example, "1 year, 6 months and 3 days" plus 2 days returns "1 year, 6 months and 5 days".

This instance is immutable and unaffected by this method call.

Parameters
daysToAdd Long: the days to add, positive or negative
Return
Period! a Period based on this period with the specified days added, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs

plusMonths

Added in API level 26
fun plusMonths(monthsToAdd: Long): Period!

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

This adds the amount to the months unit in a copy of this period. The years and days units are unaffected. For example, "1 year, 6 months and 3 days" plus 2 months returns "1 year, 8 months and 3 days".

This instance is immutable and unaffected by this method call.

Parameters
monthsToAdd Long: the months to add, positive or negative
Return
Period! a Period based on this period with the specified months added, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs

plusYears

Added in API level 26
fun plusYears(yearsToAdd: Long): Period!

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

This adds the amount to the years unit in a copy of this period. The months and days units are unaffected. For example, "1 year, 6 months and 3 days" plus 2 years returns "3 years, 6 months and 3 days".

This instance is immutable and unaffected by this method call.

Parameters
yearsToAdd Long: the years to add, positive or negative
Return
Period! a Period based on this period with the specified years added, not null
Exceptions
java.lang.ArithmeticException if numeric overflow occurs

subtractFrom

Added in API level 26
fun subtractFrom(temporal: Temporal!): Temporal!

Subtracts this period from the specified temporal object.

This returns a temporal object of the same observable type as the input with this period subtracted. If the temporal has a chronology, it must be the ISO chronology.

In most cases, it is clearer to reverse the calling pattern by using Temporal#minus(TemporalAmount).

// these two lines are equivalent, but the second approach is recommended
    dateTime = thisPeriod.subtractFrom(dateTime);
    dateTime = dateTime.minus(thisPeriod);
  

The calculation operates as follows. First, the chronology of the temporal is checked to ensure it is ISO chronology or null. Second, if the months are zero, the years are subtracted if non-zero, otherwise the combination of years and months is subtracted if non-zero. Finally, any days are subtracted.

This approach ensures that a partial period can be subtracted from a partial date. For example, a period of years and/or months can be subtracted from a YearMonth, but a period including days cannot. The approach also subtracts years and months together when necessary, which ensures correct behaviour at the end of the month.

This instance is immutable and unaffected by this method call.

Parameters
temporal Temporal!: the temporal object to adjust, not null
Return
Temporal! an object of the same type with the adjustment made, not null
Exceptions
java.time.DateTimeException if unable to subtract
java.lang.ArithmeticException if numeric overflow occurs

toString

Added in API level 26
fun toString(): String

Outputs this period as a String, such as P6Y3M1D.

The output will be in the ISO-8601 period format. A zero period will be represented as zero days, 'P0D'.

Return
String a string representation of this period, not null

toTotalMonths

Added in API level 26
fun toTotalMonths(): Long

Gets the total number of months in this period.

This returns the total number of months in the period by multiplying the number of years by 12 and adding the number of months.

This instance is immutable and unaffected by this method call.

Return
Long the total number of months in the period, may be negative

withDays

Added in API level 26
fun withDays(days: Int): Period!

Returns a copy of this period with the specified amount of days.

This sets the amount of the days unit in a copy of this period. The years and months units are unaffected.

This instance is immutable and unaffected by this method call.

Parameters
days Int: the days to represent, may be negative
Return
Period! a Period based on this period with the requested days, not null

withMonths

Added in API level 26
fun withMonths(months: Int): Period!

Returns a copy of this period with the specified amount of months.

This sets the amount of the months unit in a copy of this period. The years and days units are unaffected.

The months unit is not automatically normalized with the years unit. This means that a period of "15 months" is different to a period of "1 year and 3 months".

This instance is immutable and unaffected by this method call.

Parameters
months Int: the months to represent, may be negative
Return
Period! a Period based on this period with the requested months, not null

withYears

Added in API level 26
fun withYears(years: Int): Period!

Returns a copy of this period with the specified amount of years.

This sets the amount of the years unit in a copy of this period. The months and days units are unaffected.

The months unit is not automatically normalized with the years unit. This means that a period of "15 months" is different to a period of "1 year and 3 months".

This instance is immutable and unaffected by this method call.

Parameters
years Int: the years to represent, may be negative
Return
Period! a Period based on this period with the requested years, not null

Properties

ZERO

Added in API level 26
static val ZERO: Period!

A constant for a period of zero.