Package java.time.chrono

Interface ChronoPeriod

  • All Superinterfaces:
    TemporalAmount
    All Known Implementing Classes:
    Period
    public interface ChronoPeriod
extends TemporalAmount
    A date-based amount of time, such as '3 years, 4 months and 5 days' in an arbitrary chronology, intended for advanced globalization use cases.

    This interface models a date-based amount of time in a calendar system. While most calendar systems use years, months and days, some do not. Therefore, this interface operates solely in terms of a set of supported units that are defined by the Chronology. The set of supported units is fixed for a given chronology. The amount of a supported unit may be set to zero.

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

    This interface must be implemented with care to ensure other classes operate correctly. All implementations that can be instantiated must be final, immutable and thread-safe. Subclasses should be Serializable wherever possible.

    • Method Detail

      • get

        long get​(TemporalUnit unit)
        Gets the value of the requested unit.

        The supported units are chronology specific. They will typically be YEARS, MONTHS and DAYS. Requesting an unsupported unit will throw an exception.

        Specified by:
        get in interface TemporalAmount
        Parameters:
        unit - the TemporalUnit for which to return the value
        Returns:
        the long value of the unit
        Throws:
        DateTimeException - if the unit is not supported
        UnsupportedTemporalTypeException - if the unit is not supported

      • getUnits

        java.util.List<TemporalUnit> getUnits()
        Gets the set of units supported by this period.

        The supported units are chronology specific. They will typically be YEARS, MONTHS and DAYS. They are returned in order from largest to smallest.

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

        Specified by:
        getUnits in interface TemporalAmount
        Returns:
        a list containing the supported units, not null

      • getChronology

        Chronology getChronology()
        Gets the chronology that defines the meaning of the supported units.

        The period is defined by the chronology. It controls the supported units and restricts addition/subtraction to ChronoLocalDate instances of the same chronology.

        Returns:
        the chronology defining the period, not null

      • isZero

        boolean isZero()
        Checks if all the supported units of this period are zero.
        Returns:
        true if this period is zero-length

      • isNegative

        boolean isNegative()
        Checks if any of the supported units of this period are negative.
        Returns:
        true if any unit of this period is negative

      • plus

        ChronoPeriod plus​(TemporalAmount amountToAdd)
        Returns a copy of this period with the specified period added.

        If the specified amount is a ChronoPeriod then it must have the same chronology as this period. Implementations may choose to accept or reject other TemporalAmount implementations.

        This instance is immutable and unaffected by this method call.

        Parameters:
        amountToAdd - the period to add, not null
        Returns:
        a ChronoPeriod based on this period with the requested period added, not null

      • minus

        ChronoPeriod minus​(TemporalAmount amountToSubtract)
        Returns a copy of this period with the specified period subtracted.

        If the specified amount is a ChronoPeriod then it must have the same chronology as this period. Implementations may choose to accept or reject other TemporalAmount implementations.

        This instance is immutable and unaffected by this method call.

        Parameters:
        amountToSubtract - the period to subtract, not null
        Returns:
        a ChronoPeriod based on this period with the requested period subtracted, not null

      • multipliedBy

        ChronoPeriod multipliedBy​(int scalar)
        Returns a new instance with each amount in this period in this period multiplied by the specified scalar.

        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.

        Parameters:
        scalar - the scalar to multiply by, not null
        Returns:
        a ChronoPeriod based on this period with the amounts multiplied by the scalar, not null

      • negated

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

        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.

        Returns:
        a ChronoPeriod based on this period with the amounts negated, not null

      • normalized

        ChronoPeriod normalized()
        Returns a copy of this period with the amounts of each unit normalized.

        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".

        This instance is immutable and unaffected by this method call.

        Returns:
        a ChronoPeriod based on this period with the amounts of each unit normalized, not null

      • addTo

        Temporal addTo​(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.

        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 specified temporal must have the same chronology as this period. This returns a temporal with the non-zero supported units added.

        This instance is immutable and unaffected by this method call.

        Specified by:
        addTo in interface TemporalAmount
        Parameters:
        temporal - the temporal object to adjust, not null
        Returns:
        an object of the same type with the adjustment made, not null
        Throws:
        DateTimeException - if unable to add

      • subtractFrom

        Temporal subtractFrom​(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.

        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 specified temporal must have the same chronology as this period. This returns a temporal with the non-zero supported units subtracted.

        This instance is immutable and unaffected by this method call.

        Specified by:
        subtractFrom in interface TemporalAmount
        Parameters:
        temporal - the temporal object to adjust, not null
        Returns:
        an object of the same type with the adjustment made, not null
        Throws:
        DateTimeException - if unable to subtract

      • equals

        boolean equals​(@Nullable
               java.lang.Object obj)
        Checks if this period is equal to another period, including the chronology.

        Compares this period with another ensuring that the type, each amount and the chronology are the same. Note that this means that a period of "15 Months" is not equal to a period of "1 Year and 3 Months".

        Overrides:
        equals in class java.lang.Object
        Parameters:
        obj - the object to check, null returns false
        Returns:
        true if this is equal to the other period
        See Also:
        Object.hashCode(), HashMap

      • hashCode

        int hashCode()
        A hash code for this period.
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        a suitable hash code
        See Also:
        Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

      • toString

        java.lang.String toString()
        Outputs this period as a String.

        The output will include the period amounts and chronology.

        Overrides:
        toString in class java.lang.Object
        Returns:
        a string representation of this period, not null