Temporal
Related Doc:
package temporal
Gets the value of the specified field as a long.
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.
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.
the field to get, not null
the value for the field
ArithmeticException if numeric overflow occurs
DateTimeException if a value for the field cannot be obtained
Checks if the specified unit is supported.
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.
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.
the unit to check, null returns false
true if this date-time can be queried for the unit, false if not
Checks if the specified field is supported.
Checks if the specified field is supported.
This checks if the date-time can be queried for the specified field.
If false, then calling the range and get
methods will throw an exception.
Implementations must check and handle all fields defined in ChronoField.
If the field is supported, then true is returned, otherwise 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.
Implementations must not alter this object.
the field to check, null returns false
true if this date-time can be queried for the field, false if not
Returns an object of the same type as this object with the specified period added.
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.
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.
the amount of the specified unit to add, may be negative
the unit of the period to add, not null
an object of the same type with the specified period added, not null
ArithmeticException if numeric overflow occurs
DateTimeException if the unit cannot be added
Calculates the period between this temporal and another temporal in terms of the specified unit.
Calculates the period between this temporal and another temporal in terms of the specified unit.
This calculates the period between two temporals in terms of a single unit.
The start and end points are this and the specified temporal.
The result will be negative if the end is before the start.
For example, the period in hours between two temporal objects can be
calculated using startTime.until(endTime, HOURS).
The calculation returns a whole number, representing the number of complete units between the two temporals. For example, the period in hours between the times 11:30 and 13:29 will only be one hour as it is one minute short of two hours.
There are two equivalent ways of using this method.
The first is to invoke this method directly.
The second is to use Temporal):
// these two lines are equivalent between = thisUnit.between(start, end); between = start.until(end, thisUnit);The choice should be made based on which makes the code more readable.
For example, this method allows the number of days between two dates to be calculated:
val daysBetween: Long = DAYS.between(start, end); // or alternatively val daysBetween: Long = start.until(end, DAYS);
Implementations must begin by checking to ensure that the input temporal
object is of the same observable type as the implementation.
They must then perform the calculation for all instances of ChronoUnit.
A DateTimeException must be thrown for ChronoUnit
instances that are unsupported.
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.
In summary, implementations must behave in a manner equivalent to this code:
// check input temporal is the same type as this class
if (unit instanceof ChronoUnit) {
// if unit is supported, then calculate and return result
// else throw DateTimeException for unsupported units
}
return unit.between(this, endTemporal);
The target object must not be altered by this method.
the end temporal, of the same type as this object, not null
the unit to measure the period in, not null
the amount of the period between this and the end
ArithmeticException if numeric overflow occurs
DateTimeException if the period cannot be calculated
Returns an object of the same type as this object with the specified field altered.
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.
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.
the field to set in the result, not null
the new value of the field in the result
an object of the same type with the specified field set, not null
ArithmeticException if numeric overflow occurs
DateTimeException if the field cannot be set
Gets the value of the specified field as an int.
Gets the value of the specified field as an int.
This queries the date-time for the value for the specified field. The returned value will always be within 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.
Implementations must check and handle all fields defined in ChronoField.
If the field is supported and has an int range, 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.
the field to get, not null
the value for the field, within the valid range of values
ArithmeticException if numeric overflow occurs
DateTimeException if the value is outside the range of valid values for the field
Returns an object of the same type as this object with the specified period subtracted.
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.
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.
the amount of the specified unit to subtract, may be negative
the unit of the period to subtract, not null
an object of the same type with the specified period subtracted, not null
ArithmeticException if numeric overflow occurs
DateTimeException if the unit cannot be subtracted
Returns an object of the same type as this object with an amount subtracted.
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.
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.
the amount to subtract, not null
an object of the same type with the specified adjustment made, not null
ArithmeticException if numeric overflow occurs
DateTimeException if the subtraction cannot be made
Returns an object of the same type as this object with an amount added.
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.
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.
the amount to add, not null
an object of the same type with the specified adjustment made, not null
ArithmeticException if numeric overflow occurs
DateTimeException if the addition cannot be made
Queries this date-time.
Queries this date-time.
This queries this date-time using the specified query strategy object.
Queries are a key tool for extracting information from date-times. They exists to externalize the process of querying, permitting different approaches, as per the strategy design pattern. Examples might be a query that checks if the date is the day before February 29th in a leap year, or calculates the number of days to your next birthday.
The most common query implementations are method references, such as
LocalDate::from and ZoneId::from.
Further implementations are on TemporalQueries.
Queries may also be defined by applications.
Implementations of this method must behave as follows:
public <R> R query(TemporalQuery<R> type) {
// only include an if statement if the implementation can return it
if (query == TemporalQueries.zoneId()) return // the ZoneId
if (query == TemporalQueries.chronology()) return // the Chrono
if (query == TemporalQueries.precision()) return // the precision
// call default method
return super.query(query);
}
the type of the result
the query to invoke, not null
the query result, null may be returned (defined by the query)
ArithmeticException if numeric overflow occurs
DateTimeException if unable to query
Gets the range of valid values for the specified field.
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.
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.
the field to query the range for, not null
the range of valid values for the field, not null
DateTimeException if the range for the field cannot be obtained
Returns an adjusted object of the same type as this object with the adjustment made.
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
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.
the adjuster to use, not null
an object of the same type with the specified adjustment made, not null
ArithmeticException if numeric overflow occurs
DateTimeException if unable to make the adjustment
Framework-level interface defining read-write access to a temporal object, such as a date, time, offset or some combination of these.
This is the base interface type for date, time and offset objects that are complete enough to be manipulated using plus and minus. It is implemented by those classes that can provide and manipulate information as
fieldsorqueries. SeeTemporalAccessorfor the read-only version of this interface.Most date and time information can be represented as a number. These are modeled using
TemporalFieldwith the number held using alongto handle large values. Year, month and day-of-month are simple examples of fields, but they also include instant and offsets. SeeChronoFieldfor the standard set of fields.Two pieces of date/time information cannot be represented by numbers, the
chronologyand thetime-zone. These can be accessed viaqueriesusing the static methods defined onTemporalQueries.This interface is a framework-level interface that should not be widely used in application code. Instead, applications should create and pass around instances of concrete types, such as
LocalDate. There are many reasons for this, part of which is that implementations of this interface may be in calendar systems other than ISO. SeeChronoLocalDatefor a fuller discussion of the issues.When to implement
A class should implement this interface if it meets three criteria:
TemporalAccessorFour examples make this clear:
LocalDateimplements this interface as it represents a set of fields that are contiguous from days to forever and require no external information to determine the validity of each date. It is therefore able to implement plus/minus correctly.LocalTimeimplements this interface as it represents a set of fields that are contiguous from nanos to within days and require no external information to determine validity. It is able to implement plus/minus correctly, by wrapping around the day.MonthDay, the combination of month-of-year and day-of-month, does not implement this interface. While the combination is contiguous, from days to months within years, the combination does not have sufficient information to define the valid range of values for day-of-month. As such, it is unable to implement plus/minus correctly.Specification for implementors
This interface places no restrictions on the mutability of implementations, however immutability is strongly recommended. All implementations must be
Comparable.