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/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Copyright (c) 2013, Stephen Colebourne & Michael Nascimento Santos
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright notice,
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package java.time.chrono;
import java.time.DateTimeException;
import java.time.temporal.ChronoUnit;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAmount;
import java.time.temporal.TemporalUnit;
import java.time.temporal.UnsupportedTemporalTypeException;
import java.util.List;
import java.util.Objects;
/**
* 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.
* <p>
* 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 {@code Chronology}.
* The set of supported units is fixed for a given chronology.
* The amount of a supported unit may be set to zero.
* <p>
* The period is modeled as a directed amount of time, meaning that individual
* parts of the period may be negative.
*
* @implSpec
* 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.
*
* @since 1.8
*/
public interface ChronoPeriod
extends TemporalAmount {
/**
* 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.
*
* @param startDateInclusive the start date, inclusive, specifying the chronology of the calculation, not null
* @param endDateExclusive the end date, exclusive, in any chronology, not null
* @return the period between this date and the end date, not null
* @see ChronoLocalDate#until(ChronoLocalDate)
*/
public static ChronoPeriod between(ChronoLocalDate startDateInclusive, ChronoLocalDate endDateExclusive) {
Objects.requireNonNull(startDateInclusive, "startDateInclusive");
Objects.requireNonNull(endDateExclusive, "endDateExclusive");
return startDateInclusive.until(endDateExclusive);
}
//-----------------------------------------------------------------------
/**
* 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.
*
* @param unit the {@code TemporalUnit} for which to return the value
* @return the long value of the unit
* @throws DateTimeException if the unit is not supported
* @throws UnsupportedTemporalTypeException if the unit is not supported
*/
@Override
long get(TemporalUnit unit);
/**
* 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.
*
* @return a list containing the supported units, not null
*/
@Override
List<TemporalUnit> getUnits();
/**
* 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.
*
* @return the chronology defining the period, not null
*/
Chronology getChronology();
//-----------------------------------------------------------------------
/**
* Checks if all the supported units of this period are zero.
*
* @return true if this period is zero-length
*/
default boolean isZero() {
for (TemporalUnit unit : getUnits()) {
if (get(unit) != 0) {
return false;
}
}
return true;
}
/**
* Checks if any of the supported units of this period are negative.
*
* @return true if any unit of this period is negative
*/
default boolean isNegative() {
for (TemporalUnit unit : getUnits()) {
if (get(unit) < 0) {
return true;
}
}
return false;
}
//-----------------------------------------------------------------------
/**
* 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.
*
* @param amountToAdd the period to add, not null
* @return a {@code ChronoPeriod} based on this period with the requested period added, not null
* @throws ArithmeticException if numeric overflow occurs
*/
ChronoPeriod plus(TemporalAmount amountToAdd);
/**
* 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.
*
* @param amountToSubtract the period to subtract, not null
* @return a {@code ChronoPeriod} based on this period with the requested period subtracted, not null
* @throws ArithmeticException if numeric overflow occurs
*/
ChronoPeriod minus(TemporalAmount amountToSubtract);
//-----------------------------------------------------------------------
/**
* 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.
*
* @param scalar the scalar to multiply by, not null
* @return a {@code ChronoPeriod} based on this period with the amounts multiplied
* by the scalar, not null
* @throws ArithmeticException if numeric overflow occurs
*/
ChronoPeriod multipliedBy(int scalar);
/**
* 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.
*
* @return a {@code ChronoPeriod} based on this period with the amounts negated, not null
* @throws ArithmeticException if numeric overflow occurs, which only happens if
* one of the units has the value {@code Long.MIN_VALUE}
*/
default ChronoPeriod negated() {
return multipliedBy(-1);
}
//-----------------------------------------------------------------------
/**
* 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.
*
* @return a {@code ChronoPeriod} based on this period with the amounts of each
* unit normalized, not null
* @throws ArithmeticException if numeric overflow occurs
*/
ChronoPeriod normalized();
//-------------------------------------------------------------------------
/**
* 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.
*
* @param temporal the temporal object to adjust, not null
* @return an object of the same type with the adjustment made, not null
* @throws DateTimeException if unable to add
* @throws ArithmeticException if numeric overflow occurs
*/
@Override
Temporal addTo(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.
*
* @param temporal the temporal object to adjust, not null
* @return an object of the same type with the adjustment made, not null
* @throws DateTimeException if unable to subtract
* @throws ArithmeticException if numeric overflow occurs
*/
@Override
Temporal subtractFrom(Temporal temporal);
//-----------------------------------------------------------------------
/**
* Checks if this period is equal to another period, including the chronology.
* <p>
* 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".
*
* @param obj the object to check, null returns false
* @return true if this is equal to the other period
*/
@Override
boolean equals(Object obj);
/**
* A hash code for this period.
*
* @return a suitable hash code
*/
@Override
int hashCode();
//-----------------------------------------------------------------------
/**
* Outputs this period as a {@code String}.
* <p>
* The output will include the period amounts and chronology.
*
* @return a string representation of this period, not null
*/
@Override
String toString();
}