Module java.base
Package java.time.temporal

Interface TemporalAmount

All Known Subinterfaces:
ChronoPeriod
All Known Implementing Classes:
Duration, Period
public interface TemporalAmount
Framework-level interface defining an amount of time, such as "6 hours", "8 days" or "2 years and 3 months".

This is the base interface type for amounts of time. An amount is distinct from a date or time-of-day in that it is not tied to any specific point on the time-line.

The amount can be thought of as a Map of TemporalUnit to long, exposed via getUnits() and get(TemporalUnit). A simple case might have a single unit-value pair, such as "6 hours". A more complex case may have multiple unit-value pairs, such as "7 years, 3 months and 5 days".

There are two common implementations. Period is a date-based implementation, storing years, months and days. Duration is a time-based implementation, storing seconds and nanoseconds, but providing some access using other duration based units such as minutes, hours and fixed 24-hour days.

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 Period and Duration.

Since:
1.8

  • Method Summary

    Modifier and Type
    Method
    Description
    Temporal
    addTo(Temporal temporal)
    Adds to the specified temporal object.
    long
    get(TemporalUnit unit)
    Returns the value of the requested unit.
    List<TemporalUnit>
    getUnits()
    Returns the list of units uniquely defining the value of this TemporalAmount.
    Temporal
    subtractFrom(Temporal temporal)
    Subtracts this object from the specified temporal object.

  • Method Details

    • get

      long get(TemporalUnit unit)
      Returns the value of the requested unit. The units returned from getUnits() uniquely define the value of the TemporalAmount. A value must be returned for each unit listed in getUnits.
      Parameters:
      unit - the TemporalUnit for which to return the value
      Returns:
      the long value of the unit
      Throws:
      DateTimeException - if a value for the unit cannot be obtained
      UnsupportedTemporalTypeException - if the unit is not supported

    • getUnits

      List<TemporalUnit> getUnits()
      Returns the list of units uniquely defining the value of this TemporalAmount. The list of TemporalUnits is defined by the implementation class. The list is a snapshot of the units at the time getUnits is called and is not mutable. The units are ordered from longest duration to the shortest duration of the unit.
      Returns:
      the List of TemporalUnits; not null

    • addTo

      Temporal addTo(Temporal temporal)
      Adds to the specified temporal object.

      Adds the amount to the specified temporal object using the logic encapsulated in the implementing class.

      There are two equivalent ways of using this method. The first is to invoke this method directly. The second is to use Temporal.plus(TemporalAmount): 

         // These two lines are equivalent, but the second approach is recommended
   dateTime = amount.addTo(dateTime);
   dateTime = dateTime.plus(adder);
      It is recommended to use the second approach, plus(TemporalAmount), as it is a lot clearer to read in code.
      Parameters:
      temporal - the temporal object to add the amount to, not null
      Returns:
      an object of the same observable type with the addition made, not null
      Throws:
      DateTimeException - if unable to add
      ArithmeticException - if numeric overflow occurs

    • subtractFrom

      Temporal subtractFrom(Temporal temporal)
      Subtracts this object from the specified temporal object.

      Subtracts the amount from the specified temporal object using the logic encapsulated in the implementing class.

      There are two equivalent ways of using this method. The first is to invoke this method directly. The second is to use Temporal.minus(TemporalAmount): 

         // these two lines are equivalent, but the second approach is recommended
   dateTime = amount.subtractFrom(dateTime);
   dateTime = dateTime.minus(amount);
      It is recommended to use the second approach, minus(TemporalAmount), as it is a lot clearer to read in code.
      Parameters:
      temporal - the temporal object to subtract the amount from, not null
      Returns:
      an object of the same observable type with the subtraction made, not null
      Throws:
      DateTimeException - if unable to subtract
      ArithmeticException - if numeric overflow occurs