src/temporal/ChronoUnit.js
/**
* @copyright (c) 2016, Philipp Thuerwaechter & Pattrick Hueper
* @copyright (c) 2007-present, Stephen Colebourne & Michael Nascimento Santos
* @license BSD-3-Clause (see LICENSE in the root directory of this source tree)
*/
import {MathUtil} from '../MathUtil';
import {Duration} from '../Duration';
import {Year} from '../Year';
import {TemporalUnit} from './TemporalUnit';
/**
* A standard set of date periods units.
* <p>
* This set of units provide unit-based access to manipulate a date, time or date-time.
* The standard set of units can be extended by implementing {@link TemporalUnit}.
* <p>
* These units are intended to be applicable in multiple calendar systems.
* For example, most non-ISO calendar systems define units of years, months and days,
* just with slightly different rules.
* The documentation of each unit explains how it operates.
*
* <h3>Static properties of Class {@link ChronoUnit}</h3>
*
* ChronoUnit.NANOS
*
* Unit that represents the concept of a nanosecond, the smallest supported unit of time.
* For the ISO calendar system, it is equal to the 1,000,000,000th part of the second unit.
*
* ChronoUnit.MICROS
*
* Unit that represents the concept of a microsecond.
* For the ISO calendar system, it is equal to the 1,000,000th part of the second unit.
*
* ChronoUnit.MILLIS
*
* Unit that represents the concept of a millisecond.
* For the ISO calendar system, it is equal to the 1000th part of the second unit.
*
* ChronoUnit.SECONDS
*
* Unit that represents the concept of a second.
* For the ISO calendar system, it is equal to the second in the SI system
* of units, except around a leap-second.
*
* ChronoUnit.MINUTES
*
* Unit that represents the concept of a minute.
* For the ISO calendar system, it is equal to 60 seconds.
*
* ChronoUnit.HOURS
*
* Unit that represents the concept of an hour.
* For the ISO calendar system, it is equal to 60 minutes.
*
* ChronoUnit.HALF_DAYS
*
* Unit that represents the concept of half a day, as used in AM/PM.
* For the ISO calendar system, it is equal to 12 hours.
*
* ChronoUnit.DAYS
*
* Unit that represents the concept of a day.
* For the ISO calendar system, it is the standard day from midnight to midnight.
* The estimated duration of a day is {@code 24 Hours}.
* <p>
* When used with other calendar systems it must correspond to the day defined by
* the rising and setting of the Sun on Earth. It is not required that days begin
* at midnight - when converting between calendar systems, the date should be
* equivalent at midday.
*
* ChronoUnit.WEEKS
*
* Unit that represents the concept of a week.
* For the ISO calendar system, it is equal to 7 days.
* <p>
* When used with other calendar systems it must correspond to an integral number of days.
*
* ChronoUnit.MONTHS
*
* Unit that represents the concept of a month.
* For the ISO calendar system, the length of the month varies by month-of-year.
* The estimated duration of a month is one twelfth of {@code 365.2425 Days}.
* <p>
* When used with other calendar systems it must correspond to an integral number of days.
*
* ChronoUnit.YEARS
*
* Unit that represents the concept of a year.
* For the ISO calendar system, it is equal to 12 months.
* The estimated duration of a year is {@code 365.2425 Days}.
* <p>
* When used with other calendar systems it must correspond to an integral number of days
* or months roughly equal to a year defined by the passage of the Earth around the Sun.
*
* ChronoUnit.DECADES
*
* Unit that represents the concept of a decade.
* For the ISO calendar system, it is equal to 10 years.
* <p>
* When used with other calendar systems it must correspond to an integral number of days
* and is normally an integral number of years.
*
* ChronoUnit.CENTURIES
*
* Unit that represents the concept of a century.
* For the ISO calendar system, it is equal to 100 years.
* <p>
* When used with other calendar systems it must correspond to an integral number of days
* and is normally an integral number of years.
*
* ChronoUnit.MILLENNIA
*
* Unit that represents the concept of a millennium.
* For the ISO calendar system, it is equal to 1000 years.
* <p>
* When used with other calendar systems it must correspond to an integral number of days
* and is normally an integral number of years.
*
* ChronoUnit.ERAS
*
* Unit that represents the concept of an era.
* The ISO calendar system doesn't have eras thus it is impossible to add
* an era to a date or date-time.
* The estimated duration of the era is artificially defined as {Year.MAX_VALUE} + 1.
* <p>
* When used with other calendar systems there are no restrictions on the unit.
*
* ChronoUnit.FOREVER
*
* Artificial unit that represents the concept of forever.
* This is primarily used with {@link TemporalField} to represent unbounded fields
* such as the year or era.
* The estimated duration of the era is artificially defined as the largest duration
* supported by {@code Duration}.
*
*/
export class ChronoUnit extends TemporalUnit {
/**
*
* @param {String} name
* @param {Duration} estimatedDuration
*/
constructor (name, estimatedDuration) {
super();
this._name = name;
this._duration = estimatedDuration;
}
//-----------------------------------------------------------------------
/**
* Gets the estimated duration of this unit in the ISO calendar system.
* <p>
* All of the units in this class have an estimated duration.
* Days vary due to daylight saving time, while months have different lengths.
*
* @return {Duration} the estimated duration of this unit, not null
*/
duration() {
return this._duration;
}
/**
* Checks if the duration of the unit is an estimate.
* <p>
* All time units in this class are considered to be accurate, while all date
* units in this class are considered to be estimated.
* <p>
* This definition ignores leap seconds, but considers that Days vary due to
* daylight saving time and months have different lengths.
*
* @return {boolean} true if the duration is estimated, false if accurate
*/
isDurationEstimated() {
return this.isDateBased() || this === ChronoUnit.FOREVER;
}
//-----------------------------------------------------------------------
/**
* Checks if this unit is a date unit.
*
* @return true if a date unit, false if a time unit
*/
isDateBased() {
return this.compareTo(ChronoUnit.DAYS) >= 0 && this !== ChronoUnit.FOREVER;
}
/**
* Checks if this unit is a time unit.
*
* @return true if a time unit, false if a date unit
*/
isTimeBased() {
return this.compareTo(ChronoUnit.DAYS) < 0;
}
//-----------------------------------------------------------------------
/**
* Checks if this unit is supported by the specified temporal object.
* <p>
* This checks that the implementing date-time can add/subtract this unit.
* This can be used to avoid throwing an exception.
* <p>
* This default implementation derives the value using
* {@link Temporal#plus(long, TemporalUnit)}.
*
* @param {Temporal} temporal the temporal object to check, not null
* @return {boolean} true if the unit is supported
*/
isSupportedBy(temporal) {
if (this === ChronoUnit.FOREVER) {
return false;
}
/* TODO: classes not implemented yet */
/*
if (temporal instanceof ChronoLocalDate) {
return isDateBased();
}
if (temporal instanceof ChronoLocalDateTime || temporal instanceof ChronoZonedDateTime) {
return true;
}
*/
try {
temporal.plus(1, this);
return true;
} catch (e) {
try {
temporal.plus(-1, this);
return true;
} catch (e2) {
return false;
}
}
}
/**
* Returns a copy of the specified temporal object with the specified period added.
* <p>
* The period added is a multiple of this unit. For example, this method
* could be used to add "3 days" to a date by calling this method on the
* instance representing "days", passing the date and the period "3".
* The period to be added may be negative, which is equivalent to subtraction.
* <p>
* There are two equivalent ways of using this method.
* The first is to invoke this method directly.
* The second is to use {@link Temporal#plus(long, TemporalUnit)}:
* <pre>
* // these two lines are equivalent, but the second approach is recommended
* temporal = thisUnit.addTo(temporal);
* temporal = temporal.plus(thisUnit);
* </pre>
* It is recommended to use the second approach, {@code plus(TemporalUnit)},
* as it is a lot clearer to read in code.
* <p>
* Implementations should perform any queries or calculations using the units
* available in {@link ChronoUnit} or the fields available in {@link ChronoField}.
* If the unit is not supported an {@code UnsupportedTemporalTypeException} must be thrown.
* <p>
* Implementations must not alter the specified temporal object.
* Instead, an adjusted copy of the original must be returned.
* This provides equivalent, safe behavior for immutable and mutable implementations.
*
* @param {Temporal} temporal the temporal object to adjust, not null
* @param {Number} amount the amount of this unit to add, positive or negative
* @return {Temporal} the adjusted temporal object, not null
* @throws DateTimeException if the amount cannot be added
* @throws UnsupportedTemporalTypeException if the unit is not supported by the temporal
*/
addTo(temporal, amount) {
return temporal.plus(amount, this);
}
//-----------------------------------------------------------------------
/**
* Calculates the amount of time between two temporal objects.
* <p>
* This calculates the amount in terms of this unit. The start and end
* points are supplied as temporal objects and must be of compatible types.
* The implementation will convert the second type to be an instance of the
* first type before the calculating the amount.
* The result will be negative if the end is before the start.
* For example, the amount in hours between two temporal objects can be
* calculated using {@code HOURS.between(startTime, endTime)}.
* <p>
* The calculation returns a whole number, representing the number of
* complete units between the two temporals.
* For example, the amount in hours between the times 11:30 and 13:29
* will only be one hour as it is one minute short of two hours.
* <p>
* There are two equivalent ways of using this method.
* The first is to invoke this method directly.
* The second is to use {@link Temporal#until(Temporal, TemporalUnit)}:
* <pre>
* // these two lines are equivalent
* between = thisUnit.between(start, end);
* between = start.until(end, thisUnit);
* </pre>
* The choice should be made based on which makes the code more readable.
* <p>
* For example, this method allows the number of days between two dates to
* be calculated:
* <pre>
* daysBetween = DAYS.between(start, end);
* // or alternatively
* daysBetween = start.until(end, DAYS);
* </pre>
* <p>
* Implementations should perform any queries or calculations using the units
* available in {@link ChronoUnit} or the fields available in {@link ChronoField}.
* If the unit is not supported an {@code UnsupportedTemporalTypeException} must be thrown.
* Implementations must not alter the specified temporal objects.
*
* @implSpec
* Implementations must begin by checking to if the two temporals have the
* same type using {@code .constructor.name}. If they do not, then the result must be
* obtained by calling {@code temporal1.until(temporal2, this)}.
*
* @param {Temporal} temporal1 the base temporal object, not null
* @param {Temporal} temporal2 the other temporal object, exclusive, not null
* @return {Number} the amount of time between temporal1 and temporal2
* in terms of this unit; positive if temporal2 is later than
* temporal1, negative if earlier
* @throws DateTimeException if the amount cannot be calculated, or the end
* temporal cannot be converted to the same type as the start temporal
* @throws UnsupportedTemporalTypeException if the unit is not supported by the temporal
* @throws ArithmeticException if numeric overflow occurs
*/
between(temporal1, temporal2) {
return temporal1.until(temporal2, this);
}
//-----------------------------------------------------------------------
toString() {
return this._name;
}
/**
* Compares this ChronoUnit to the specified {TemporalUnit}.
* <p>
* The comparison is based on the total length of the durations.
*
* @param {TemporalUnit} other the other unit to compare to, not null
* @return the comparator value, negative if less, positive if greater
*/
compareTo(other) {
return this.duration().compareTo(other.duration());
}
}
export function _init() {
/**
* Unit that represents the concept of a nanosecond, the smallest supported unit of time.
* For the ISO calendar system, it is equal to the 1,000,000,000th part of the second unit.
*/
ChronoUnit.NANOS = new ChronoUnit('Nanos', Duration.ofNanos(1));
/**
* Unit that represents the concept of a microsecond.
* For the ISO calendar system, it is equal to the 1,000,000th part of the second unit.
*/
ChronoUnit.MICROS = new ChronoUnit('Micros', Duration.ofNanos(1000));
/**
* Unit that represents the concept of a millisecond.
* For the ISO calendar system, it is equal to the 1000th part of the second unit.
*/
ChronoUnit.MILLIS = new ChronoUnit('Millis', Duration.ofNanos(1000000));
/**
* Unit that represents the concept of a second.
* For the ISO calendar system, it is equal to the second in the SI system
* of units, except around a leap-second.
*/
ChronoUnit.SECONDS = new ChronoUnit('Seconds', Duration.ofSeconds(1));
/**
* Unit that represents the concept of a minute.
* For the ISO calendar system, it is equal to 60 seconds.
*/
ChronoUnit.MINUTES = new ChronoUnit('Minutes', Duration.ofSeconds(60));
/**
* Unit that represents the concept of an hour.
* For the ISO calendar system, it is equal to 60 minutes.
*/
ChronoUnit.HOURS = new ChronoUnit('Hours', Duration.ofSeconds(3600));
/**
* Unit that represents the concept of half a day, as used in AM/PM.
* For the ISO calendar system, it is equal to 12 hours.
*/
ChronoUnit.HALF_DAYS = new ChronoUnit('HalfDays', Duration.ofSeconds(43200));
/**
* Unit that represents the concept of a day.
* For the ISO calendar system, it is the standard day from midnight to midnight.
* The estimated duration of a day is {@code 24 Hours}.
* <p>
* When used with other calendar systems it must correspond to the day defined by
* the rising and setting of the Sun on Earth. It is not required that days begin
* at midnight - when converting between calendar systems, the date should be
* equivalent at midday.
*/
ChronoUnit.DAYS = new ChronoUnit('Days', Duration.ofSeconds(86400));
/**
* Unit that represents the concept of a week.
* For the ISO calendar system, it is equal to 7 days.
* <p>
* When used with other calendar systems it must correspond to an integral number of days.
*/
ChronoUnit.WEEKS = new ChronoUnit('Weeks', Duration.ofSeconds(7 * 86400));
/**
* Unit that represents the concept of a month.
* For the ISO calendar system, the length of the month varies by month-of-year.
* The estimated duration of a month is one twelfth of {@code 365.2425 Days}.
* <p>
* When used with other calendar systems it must correspond to an integral number of days.
*/
ChronoUnit.MONTHS = new ChronoUnit('Months', Duration.ofSeconds(31556952 / 12));
/**
* Unit that represents the concept of a year.
* For the ISO calendar system, it is equal to 12 months.
* The estimated duration of a year is {@code 365.2425 Days}.
* <p>
* When used with other calendar systems it must correspond to an integral number of days
* or months roughly equal to a year defined by the passage of the Earth around the Sun.
*/
ChronoUnit.YEARS = new ChronoUnit('Years', Duration.ofSeconds(31556952));
/**
* Unit that represents the concept of a decade.
* For the ISO calendar system, it is equal to 10 years.
* <p>
* When used with other calendar systems it must correspond to an integral number of days
* and is normally an integral number of years.
*/
ChronoUnit.DECADES = new ChronoUnit('Decades', Duration.ofSeconds(31556952 * 10));
/**
* Unit that represents the concept of a century.
* For the ISO calendar system, it is equal to 100 years.
* <p>
* When used with other calendar systems it must correspond to an integral number of days
* and is normally an integral number of years.
*/
ChronoUnit.CENTURIES = new ChronoUnit('Centuries', Duration.ofSeconds(31556952 * 100));
/**
* Unit that represents the concept of a millennium.
* For the ISO calendar system, it is equal to 1000 years.
* <p>
* When used with other calendar systems it must correspond to an integral number of days
* and is normally an integral number of years.
*/
ChronoUnit.MILLENNIA = new ChronoUnit('Millennia', Duration.ofSeconds(31556952 * 1000));
/**
* Unit that represents the concept of an era.
* The ISO calendar system doesn't have eras thus it is impossible to add
* an era to a date or date-time.
* The estimated duration of the era is artificially defined as {Year.MAX_VALUE} + 1.
* <p>
* When used with other calendar systems there are no restrictions on the unit.
*/
ChronoUnit.ERAS = new ChronoUnit('Eras', Duration.ofSeconds(31556952 * (Year.MAX_VALUE + 1)));
/**
* Artificial unit that represents the concept of forever.
* This is primarily used with {@link TemporalField} to represent unbounded fields
* such as the year or era.
* The estimated duration of the era is artificially defined as the largest duration
* supported by {@code Duration}.
*/
ChronoUnit.FOREVER = new ChronoUnit('Forever', Duration.ofSeconds(MathUtil.MAX_SAFE_INTEGER, 999999999));
}
