ChronoUnit.java
/*
* Copyright (c) 2007-present, Stephen Colebourne & Michael Nascimento Santos
*
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* modification, are permitted provided that the following conditions are met:
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* this list of conditions and the following disclaimer in the documentation
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*
* * Neither the name of JSR-310 nor the names of its contributors
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*
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package org.threeten.bp.temporal;
import org.threeten.bp.Duration;
import org.threeten.bp.chrono.ChronoLocalDate;
import org.threeten.bp.chrono.ChronoLocalDateTime;
import org.threeten.bp.chrono.ChronoZonedDateTime;
/**
* 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>Specification for implementors</h3>
* This is a final, immutable and thread-safe enum.
*/
public enum ChronoUnit implements TemporalUnit {
/**
* 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.
*/
NANOS("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.
*/
MICROS("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.
*/
MILLIS("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.
*/
SECONDS("Seconds", Duration.ofSeconds(1)),
/**
* Unit that represents the concept of a minute.
* For the ISO calendar system, it is equal to 60 seconds.
*/
MINUTES("Minutes", Duration.ofSeconds(60)),
/**
* Unit that represents the concept of an hour.
* For the ISO calendar system, it is equal to 60 minutes.
*/
HOURS("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.
*/
HALF_DAYS("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.
*/
DAYS("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.
*/
WEEKS("Weeks", Duration.ofSeconds(7 * 86400L)),
/**
* 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.
*/
MONTHS("Months", Duration.ofSeconds(31556952L / 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.
*/
YEARS("Years", Duration.ofSeconds(31556952L)),
/**
* 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.
*/
DECADES("Decades", Duration.ofSeconds(31556952L * 10L)),
/**
* 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.
*/
CENTURIES("Centuries", Duration.ofSeconds(31556952L * 100L)),
/**
* 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.
*/
MILLENNIA("Millennia", Duration.ofSeconds(31556952L * 1000L)),
/**
* 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 {@code 1,000,000,000 Years}.
* <p>
* When used with other calendar systems there are no restrictions on the unit.
*/
ERAS("Eras", Duration.ofSeconds(31556952L * 1000000000L)),
/**
* 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}.
*/
FOREVER("Forever", Duration.ofSeconds(Long.MAX_VALUE, 999999999));
private final String name;
private final Duration duration;
private ChronoUnit(String name, Duration estimatedDuration) {
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 the estimated duration of this unit, not null
*/
@Override
public Duration getDuration() {
return 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 true if the duration is estimated, false if accurate
*/
@Override
public boolean isDurationEstimated() {
return isDateBased() || this == FOREVER;
}
//-----------------------------------------------------------------------
/**
* Checks if this unit is a date unit.
*
* @return true if a date unit, false if a time unit
*/
public boolean isDateBased() {
return this.compareTo(DAYS) >= 0 && this != FOREVER;
}
/**
* Checks if this unit is a time unit.
*
* @return true if a time unit, false if a date unit
*/
public boolean isTimeBased() {
return this.compareTo(DAYS) < 0;
}
//-----------------------------------------------------------------------
@Override
public boolean isSupportedBy(Temporal temporal) {
if (this == FOREVER) {
return false;
}
if (temporal instanceof ChronoLocalDate) {
return isDateBased();
}
if (temporal instanceof ChronoLocalDateTime || temporal instanceof ChronoZonedDateTime) {
return true;
}
try {
temporal.plus(1, this);
return true;
} catch (RuntimeException ex) {
try {
temporal.plus(-1, this);
return true;
} catch (RuntimeException ex2) {
return false;
}
}
}
@SuppressWarnings("unchecked")
@Override
public <R extends Temporal> R addTo(R dateTime, long periodToAdd) {
return (R) dateTime.plus(periodToAdd, this);
}
//-----------------------------------------------------------------------
@Override
public long between(Temporal temporal1, Temporal temporal2) {
return temporal1.until(temporal2, this);
}
//-----------------------------------------------------------------------
@Override
public String toString() {
return name;
}
}