Period

A date-based amount of time _in the ISO-8601 calendar system, such as '2 years, 3 months and 4 days'. !(p) This class models a quantity or amount of time _in terms of years, months and days. See {@link Duration} for the time-based equivalent to this class. !(p) Durations and periods differ _in their treatment of daylight savings time when added to {@link ZonedDateTime}. A {@code Duration} will add an exact number of seconds, thus a duration of one day is always exactly 24 hours. By contrast, a {@code Period} will add a conceptual day, trying to maintain the local time. !(p) 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 {@code Period} will add the conceptual day and result _in a {@code ZonedDateTime} at 18:00 the following day. By contrast, the {@code Duration} will add exactly 24 hours, resulting _in a {@code ZonedDateTime} at 19:00 the following day (assuming a one hour DST gap). !(p) The supported units of a period are {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}. All three fields are always present, but may be set to zero. !(p) 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. !(p) The period is modeled as a directed amount of time, meaning that individual parts of the period may be negative.

!(p) This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a> class; use of identity-sensitive operations (including reference equality ({@code ==}), identity hash code, or synchronization) on instances of {@code Period} may have unpredictable results and should be avoided. The {@code equals} method should be used for comparisons.

@implSpec This class is immutable and thread-safe.

@since 1.8

final

class Period : ChronoPeriod {

__gshared

List!(TemporalUnit) _SUPPORTED_UNITS;

static List!(TemporalUnit) SUPPORTED_UNITS();

static Period ofYears(int years);

static Period ofMonths(int months);

static Period ofWeeks(int weeks);

static Period ofDays(int days);

static Period of(int years, int months, int days);

static Period from(TemporalAmount amount);

static Period parse(string text);

static Period between(LocalDate startDateInclusive, LocalDate endDateExclusive);

this(int years, int months, int days);

long get(TemporalUnit unit);

List!(TemporalUnit) getUnits();

IsoChronology getChronology();

Period withYears(int years);

Period withMonths(int months);

Period withDays(int days);

Period plus(TemporalAmount amountToAdd);

Period plusYears(long yearsToAdd);

Period plusMonths(long monthsToAdd);

Period plusDays(long daysToAdd);

Period minus(TemporalAmount amountToSubtract);

Period minusYears(long yearsToSubtract);

Period minusMonths(long monthsToSubtract);

Period minusDays(long daysToSubtract);

Period multipliedBy(int scalar);

Period negated();

Period normalized();

long toTotalMonths();

Temporal addTo(Temporal temporal);

Temporal subtractFrom(Temporal temporal);

bool opEquals(Object obj);

size_t toHash();

string toString();

void writeExternal(DataOutput _out);

static Period readExternal(DataInput _in);

}

Constructors

this this(int years, int months, int days): Constructor.

Members

Functions

addTo Temporal addTo(Temporal temporal): Adds this period to the specified temporal object. !(p) 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. !(p) In most cases, it is clearer to reverse the calling pattern by using {@link Temporal#plus(TemporalAmount)}. !(pre) // these two lines are equivalent, but the second approach is recommended dateTime = thisPeriod.addTo(dateTime); dateTime = dateTime.plus(thisPeriod); </pre> !(p) 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. !(p) 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 {@code 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. !(p) This instance is immutable and unaffected by this method call.
get long get(TemporalUnit unit): Gets the value of the requested unit. !(p) This returns a value for each of the three supported units, {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}. All other units throw an exception.
getChronology IsoChronology getChronology(): Gets the chronology of this period, which is the ISO calendar system. !(p) The {@code 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.
getDays int getDays(): Gets the amount of days of this period. !(p) This returns the days unit.
getMonths int getMonths(): Gets the amount of months of this period. !(p) This returns the months unit. !(p) 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".
getUnits List!(TemporalUnit) getUnits(): Gets the set of units supported by this period. !(p) The supported units are {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}. They are returned _in the order years, months, days. !(p) This set can be used _in conjunction with {@link #get(TemporalUnit)} to access the entire state of the period.
getYears int getYears(): Gets the amount of years of this period. !(p) This returns the years unit. !(p) 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".
isNegative bool isNegative(): Checks if any of the three units of this period are negative. !(p) This checks whether the years, months or days units are less than zero.
isZero bool isZero(): Checks if all three units of this period are zero. !(p) A zero period has the value zero for the years, months and days units.
minus Period minus(TemporalAmount amountToSubtract): Returns a copy of this period with the specified period subtracted. !(p) This operates separately on the years, months and days. No normalization is performed. !(p) 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". !(p) The specified amount is typically an instance of {@code Period}. Other types are interpreted using {@link Period#from(TemporalAmount)}. !(p) This instance is immutable and unaffected by this method call.
minusDays Period minusDays(long daysToSubtract): Returns a copy of this period with the specified days subtracted. !(p) 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". !(p) This instance is immutable and unaffected by this method call.
minusMonths Period minusMonths(long monthsToSubtract): Returns a copy of this period with the specified months subtracted. !(p) 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". !(p) This instance is immutable and unaffected by this method call.
minusYears Period minusYears(long yearsToSubtract): Returns a copy of this period with the specified years subtracted. !(p) 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". !(p) This instance is immutable and unaffected by this method call.
multipliedBy Period multipliedBy(int scalar): Returns a new instance with each element _in this period multiplied by the specified scalar. !(p) 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.
negated Period negated(): Returns a new instance with each amount _in this period negated. !(p) 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.
normalized Period normalized(): Returns a copy of this period with the years and months normalized. !(p) 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". !(p) 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". !(p) This instance is immutable and unaffected by this method call.
opEquals bool opEquals(Object obj): Checks if this period is equal to another period. !(p) The comparison is based on the type {@code 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".
plus Period plus(TemporalAmount amountToAdd): Returns a copy of this period with the specified period added. !(p) This operates separately on the years, months and days. No normalization is performed. !(p) 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". !(p) The specified amount is typically an instance of {@code Period}. Other types are interpreted using {@link Period#from(TemporalAmount)}. !(p) This instance is immutable and unaffected by this method call.
plusDays Period plusDays(long daysToAdd): Returns a copy of this period with the specified days added. !(p) 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". !(p) This instance is immutable and unaffected by this method call.
plusMonths Period plusMonths(long monthsToAdd): Returns a copy of this period with the specified months added. !(p) 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". !(p) This instance is immutable and unaffected by this method call.
plusYears Period plusYears(long yearsToAdd): Returns a copy of this period with the specified years added. !(p) 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". !(p) This instance is immutable and unaffected by this method call.
subtractFrom Temporal subtractFrom(Temporal temporal): Subtracts this period from the specified temporal object. !(p) 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. !(p) In most cases, it is clearer to reverse the calling pattern by using {@link Temporal#minus(TemporalAmount)}. !(pre) // these two lines are equivalent, but the second approach is recommended dateTime = thisPeriod.subtractFrom(dateTime); dateTime = dateTime.minus(thisPeriod); </pre> !(p) 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. !(p) 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 {@code 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. !(p) This instance is immutable and unaffected by this method call.
toHash size_t toHash(): A hash code for this period.
toString string toString(): Outputs this period as a {@code string}, such as {@code P6Y3M1D}. !(p) The output will be _in the ISO-8601 period format. A zero period will be represented as zero days, 'P0D'.
toTotalMonths long toTotalMonths(): Gets the total number of months _in this period. !(p) This returns the total number of months _in the period by multiplying the number of years by 12 and adding the number of months. !(p) This instance is immutable and unaffected by this method call.
withDays Period withDays(int days): Returns a copy of this period with the specified amount of days. !(p) This sets the amount of the days unit _in a copy of this period. The years and months units are unaffected. !(p) This instance is immutable and unaffected by this method call.
withMonths Period withMonths(int months): Returns a copy of this period with the specified amount of months. !(p) This sets the amount of the months unit _in a copy of this period. The years and days units are unaffected. !(p) 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". !(p) This instance is immutable and unaffected by this method call.
withYears Period withYears(int years): Returns a copy of this period with the specified amount of years. !(p) This sets the amount of the years unit _in a copy of this period. The months and days units are unaffected. !(p) 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". !(p) This instance is immutable and unaffected by this method call.
writeExternal void writeExternal(DataOutput _out): Defend against malicious streams.

Static functions

SUPPORTED_UNITS List!(TemporalUnit) SUPPORTED_UNITS(): Undocumented in source. Be warned that the author may not have intended to support it.
between Period between(LocalDate startDateInclusive, LocalDate endDateExclusive): Obtains a {@code Period} consisting of the number of years, months, and days between two dates. !(p) 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 {@code 2010-01-15} to {@code 2011-03-18} is one year, two months and three days. !(p) 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.
from Period from(TemporalAmount amount): Obtains an instance of {@code Period} from a temporal amount. !(p) This obtains a period based on the specified amount. A {@code TemporalAmount} represents an amount of time, which may be date-based or time-based, which this factory extracts to a {@code Period}. !(p) The conversion loops around the set of units from the amount and uses the {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS} units to create a period. If any other units are found then an exception is thrown. !(p) If the amount is a {@code ChronoPeriod} then it must use the ISO chronology.
of Period of(int years, int months, int days): Obtains a {@code Period} representing a number of years, months and days. !(p) This creates an instance based on years, months and days.
ofDays Period ofDays(int days): Obtains a {@code Period} representing a number of days. !(p) The resulting period will have the specified days. The years and months units will be zero.
ofMonths Period ofMonths(int months): Obtains a {@code Period} representing a number of months. !(p) The resulting period will have the specified months. The years and days units will be zero.
ofWeeks Period ofWeeks(int weeks): Obtains a {@code Period} representing a number of weeks. !(p) 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.
ofYears Period ofYears(int years): Obtains a {@code Period} representing a number of years. !(p) The resulting period will have the specified years. The months and days units will be zero.
parse Period parse(string text): Obtains a {@code Period} from a text string such as {@code PnYnMnD}. !(p) This will parse the string produced by {@code toString()} which is based on the ISO-8601 period formats {@code PnYnMnD} and {@code PnW}. !(p) 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 {@code int}. !(p) 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 {@code PnYnMnD} and {@code PnW} formats. Any week-based input is multiplied by 7 and treated as a number of days. !(p) For example, the following are valid inputs: !(pre) "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) </pre>
readExternal Period readExternal(DataInput _in): Undocumented in source. Be warned that the author may not have intended to support it.

Static variables

_SUPPORTED_UNITS List!(TemporalUnit) _SUPPORTED_UNITS;: The set of supported units.

Inherited Members

From ChronoPeriod

between ChronoPeriod between(ChronoLocalDate startDateInclusive, ChronoLocalDate endDateExclusive): Obtains a {@code ChronoPeriod} consisting of amount of time between two dates. !(p) The start date is included, but the end date is not. The period is calculated using {@link ChronoLocalDate#until(ChronoLocalDate)}. As such, the calculation is chronology specific. !(p) The chronology of the first date is used. The chronology of the second date is ignored, with the date being converted to the target chronology system before the calculation starts. !(p) The result of this method can be a negative period if the end is before the start. In most cases, the positive/negative sign will be the same _in each of the supported fields.
get long get(TemporalUnit unit): Gets the value of the requested unit. !(p) The supported units are chronology specific. They will typically be {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}. Requesting an unsupported unit will throw an exception.
getUnits List!(TemporalUnit) getUnits(): Gets the set of units supported by this period. !(p) The supported units are chronology specific. They will typically be {@link ChronoUnit#YEARS YEARS}, {@link ChronoUnit#MONTHS MONTHS} and {@link ChronoUnit#DAYS DAYS}. They are returned _in order from largest to smallest. !(p) This set can be used _in conjunction with {@link #get(TemporalUnit)} to access the entire state of the period.
getChronology Chronology getChronology(): Gets the chronology that defines the meaning of the supported units. !(p) The period is defined by the chronology. It controls the supported units and restricts addition/subtraction to {@code ChronoLocalDate} instances of the same chronology.
isZero bool isZero(): Checks if all the supported units of this period are zero.
isNegative bool isNegative(): Checks if any of the supported units of this period are negative.
plus ChronoPeriod plus(TemporalAmount amountToAdd): Returns a copy of this period with the specified period added. !(p) If the specified amount is a {@code ChronoPeriod} then it must have the same chronology as this period. Implementations may choose to accept or reject other {@code TemporalAmount} implementations. !(p) This instance is immutable and unaffected by this method call.
minus ChronoPeriod minus(TemporalAmount amountToSubtract): Returns a copy of this period with the specified period subtracted. !(p) If the specified amount is a {@code ChronoPeriod} then it must have the same chronology as this period. Implementations may choose to accept or reject other {@code TemporalAmount} implementations. !(p) This instance is immutable and unaffected by this method call.
multipliedBy ChronoPeriod multipliedBy(int scalar): Returns a new instance with each amount _in this period _in this period multiplied by the specified scalar. !(p) This returns a period with each supported unit 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.
negated ChronoPeriod negated(): Returns a new instance with each amount _in this period negated. !(p) This returns a period with each supported unit 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.
normalized ChronoPeriod normalized(): Returns a copy of this period with the amounts of each unit normalized. !(p) The process of normalization is specific to each calendar system. For example, _in the ISO calendar system, the years and months are normalized but the days are not, such that "15 months" would be normalized to "1 year and 3 months". !(p) This instance is immutable and unaffected by this method call.
addTo Temporal addTo(Temporal temporal): Adds this period to the specified temporal object. !(p) This returns a temporal object of the same observable type as the input with this period added. !(p) In most cases, it is clearer to reverse the calling pattern by using {@link Temporal#plus(TemporalAmount)}. !(pre) // these two lines are equivalent, but the second approach is recommended dateTime = thisPeriod.addTo(dateTime); dateTime = dateTime.plus(thisPeriod); </pre> !(p) The specified temporal must have the same chronology as this period. This returns a temporal with the non-zero supported units added. !(p) This instance is immutable and unaffected by this method call.
subtractFrom Temporal subtractFrom(Temporal temporal): Subtracts this period from the specified temporal object. !(p) This returns a temporal object of the same observable type as the input with this period subtracted. !(p) In most cases, it is clearer to reverse the calling pattern by using {@link Temporal#minus(TemporalAmount)}. !(pre) // these two lines are equivalent, but the second approach is recommended dateTime = thisPeriod.subtractFrom(dateTime); dateTime = dateTime.minus(thisPeriod); </pre> !(p) The specified temporal must have the same chronology as this period. This returns a temporal with the non-zero supported units subtracted. !(p) This instance is immutable and unaffected by this method call.