TemporalAdjusters.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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package org.threeten.bp.temporal;
import static org.threeten.bp.temporal.ChronoField.DAY_OF_MONTH;
import static org.threeten.bp.temporal.ChronoField.DAY_OF_WEEK;
import static org.threeten.bp.temporal.ChronoField.DAY_OF_YEAR;
import static org.threeten.bp.temporal.ChronoUnit.DAYS;
import static org.threeten.bp.temporal.ChronoUnit.MONTHS;
import static org.threeten.bp.temporal.ChronoUnit.YEARS;
import org.threeten.bp.DayOfWeek;
import org.threeten.bp.jdk8.Jdk8Methods;
/**
* Common implementations of {@code TemporalAdjuster}.
* <p>
* This class provides common implementations of {@link TemporalAdjuster}.
* They are especially useful to document the intent of business logic and
* often link well to requirements.
* For example, these two pieces of code do the same thing, but the second
* one is clearer (assuming that there is a static import of this class):
* <pre>
* // direct manipulation
* date.withDayOfMonth(1).plusMonths(1).minusDays(1);
* // use of an adjuster from this class
* date.with(lastDayOfMonth());
* </pre>
* There are two equivalent ways of using a {@code TemporalAdjuster}.
* The first is to invoke the method on the interface directly.
* The second is to use {@link Temporal#with(TemporalAdjuster)}:
* <pre>
* // these two lines are equivalent, but the second approach is recommended
* dateTime = adjuster.adjustInto(dateTime);
* dateTime = dateTime.with(adjuster);
* </pre>
* It is recommended to use the second approach, {@code with(TemporalAdjuster)},
* as it is a lot clearer to read in code.
*
* <h3>Specification for implementors</h3>
* This is a thread-safe utility class.
* All returned adjusters are immutable and thread-safe.
* <p>
* The JDK 8 ofDateAdjuster(UnaryOperator) method is not backported.
*/
public final class TemporalAdjusters {
/**
* Private constructor since this is a utility class.
*/
private TemporalAdjusters() {
}
//-----------------------------------------------------------------------
/**
* Returns the "first day of month" adjuster, which returns a new date set to
* the first day of the current month.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 will return 2011-01-01.<br>
* The input 2011-02-15 will return 2011-02-01.
* <p>
* The behavior is suitable for use with most calendar systems.
* It is equivalent to:
* <pre>
* temporal.with(DAY_OF_MONTH, 1);
* </pre>
*
* @return the first day-of-month adjuster, not null
*/
public static TemporalAdjuster firstDayOfMonth() {
return Impl.FIRST_DAY_OF_MONTH;
}
/**
* Returns the "last day of month" adjuster, which returns a new date set to
* the last day of the current month.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 will return 2011-01-31.<br>
* The input 2011-02-15 will return 2011-02-28.<br>
* The input 2012-02-15 will return 2012-02-29 (leap year).<br>
* The input 2011-04-15 will return 2011-04-30.
* <p>
* The behavior is suitable for use with most calendar systems.
* It is equivalent to:
* <pre>
* long lastDay = temporal.range(DAY_OF_MONTH).getMaximum();
* temporal.with(DAY_OF_MONTH, lastDay);
* </pre>
*
* @return the last day-of-month adjuster, not null
*/
public static TemporalAdjuster lastDayOfMonth() {
return Impl.LAST_DAY_OF_MONTH;
}
/**
* Returns the "first day of next month" adjuster, which returns a new date set to
* the first day of the next month.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 will return 2011-02-01.<br>
* The input 2011-02-15 will return 2011-03-01.
* <p>
* The behavior is suitable for use with most calendar systems.
* It is equivalent to:
* <pre>
* temporal.with(DAY_OF_MONTH, 1).plus(1, MONTHS);
* </pre>
*
* @return the first day of next month adjuster, not null
*/
public static TemporalAdjuster firstDayOfNextMonth() {
return Impl.FIRST_DAY_OF_NEXT_MONTH;
}
//-----------------------------------------------------------------------
/**
* Returns the "first day of year" adjuster, which returns a new date set to
* the first day of the current year.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 will return 2011-01-01.<br>
* The input 2011-02-15 will return 2011-01-01.<br>
* <p>
* The behavior is suitable for use with most calendar systems.
* It is equivalent to:
* <pre>
* temporal.with(DAY_OF_YEAR, 1);
* </pre>
*
* @return the first day-of-year adjuster, not null
*/
public static TemporalAdjuster firstDayOfYear() {
return Impl.FIRST_DAY_OF_YEAR;
}
/**
* Returns the "last day of year" adjuster, which returns a new date set to
* the last day of the current year.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 will return 2011-12-31.<br>
* The input 2011-02-15 will return 2011-12-31.<br>
* <p>
* The behavior is suitable for use with most calendar systems.
* It is equivalent to:
* <pre>
* long lastDay = temporal.range(DAY_OF_YEAR).getMaximum();
* temporal.with(DAY_OF_YEAR, lastDay);
* </pre>
*
* @return the last day-of-year adjuster, not null
*/
public static TemporalAdjuster lastDayOfYear() {
return Impl.LAST_DAY_OF_YEAR;
}
/**
* Returns the "first day of next year" adjuster, which returns a new date set to
* the first day of the next year.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 will return 2012-01-01.
* <p>
* The behavior is suitable for use with most calendar systems.
* It is equivalent to:
* <pre>
* temporal.with(DAY_OF_YEAR, 1).plus(1, YEARS);
* </pre>
*
* @return the first day of next month adjuster, not null
*/
public static TemporalAdjuster firstDayOfNextYear() {
return Impl.FIRST_DAY_OF_NEXT_YEAR;
}
//-----------------------------------------------------------------------
/**
* Enum implementing the adjusters.
*/
private static class Impl implements TemporalAdjuster {
/** First day of month adjuster. */
private static final Impl FIRST_DAY_OF_MONTH = new Impl(0);
/** Last day of month adjuster. */
private static final Impl LAST_DAY_OF_MONTH = new Impl(1);
/** First day of next month adjuster. */
private static final Impl FIRST_DAY_OF_NEXT_MONTH = new Impl(2);
/** First day of year adjuster. */
private static final Impl FIRST_DAY_OF_YEAR = new Impl(3);
/** Last day of year adjuster. */
private static final Impl LAST_DAY_OF_YEAR = new Impl(4);
/** First day of next month adjuster. */
private static final Impl FIRST_DAY_OF_NEXT_YEAR = new Impl(5);
/** The ordinal. */
private final int ordinal;
private Impl(int ordinal) {
this.ordinal = ordinal;
}
@Override
public Temporal adjustInto(Temporal temporal) {
switch (ordinal) {
case 0: return temporal.with(DAY_OF_MONTH, 1);
case 1: return temporal.with(DAY_OF_MONTH, temporal.range(DAY_OF_MONTH).getMaximum());
case 2: return temporal.with(DAY_OF_MONTH, 1).plus(1, MONTHS);
case 3: return temporal.with(DAY_OF_YEAR, 1);
case 4: return temporal.with(DAY_OF_YEAR, temporal.range(DAY_OF_YEAR).getMaximum());
case 5: return temporal.with(DAY_OF_YEAR, 1).plus(1, YEARS);
}
throw new IllegalStateException("Unreachable");
}
}
//-----------------------------------------------------------------------
/**
* Returns the first in month adjuster, which returns a new date
* in the same month with the first matching day-of-week.
* This is used for expressions like 'first Tuesday in March'.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-12-15 for (MONDAY) will return 2011-12-05.<br>
* The input 2011-12-15 for (FRIDAY) will return 2011-12-02.<br>
* <p>
* The behavior is suitable for use with most calendar systems.
* It uses the {@code DAY_OF_WEEK} and {@code DAY_OF_MONTH} fields
* and the {@code DAYS} unit, and assumes a seven day week.
*
* @param dayOfWeek the day-of-week, not null
* @return the first in month adjuster, not null
*/
public static TemporalAdjuster firstInMonth(DayOfWeek dayOfWeek) {
Jdk8Methods.requireNonNull(dayOfWeek, "dayOfWeek");
return new DayOfWeekInMonth(1, dayOfWeek);
}
/**
* Returns the last in month adjuster, which returns a new date
* in the same month with the last matching day-of-week.
* This is used for expressions like 'last Tuesday in March'.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-12-15 for (MONDAY) will return 2011-12-26.<br>
* The input 2011-12-15 for (FRIDAY) will return 2011-12-30.<br>
* <p>
* The behavior is suitable for use with most calendar systems.
* It uses the {@code DAY_OF_WEEK} and {@code DAY_OF_MONTH} fields
* and the {@code DAYS} unit, and assumes a seven day week.
*
* @param dayOfWeek the day-of-week, not null
* @return the first in month adjuster, not null
*/
public static TemporalAdjuster lastInMonth(DayOfWeek dayOfWeek) {
Jdk8Methods.requireNonNull(dayOfWeek, "dayOfWeek");
return new DayOfWeekInMonth(-1, dayOfWeek);
}
/**
* Returns the day-of-week in month adjuster, which returns a new date
* in the same month with the ordinal day-of-week.
* This is used for expressions like the 'second Tuesday in March'.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-12-15 for (1,TUESDAY) will return 2011-12-06.<br>
* The input 2011-12-15 for (2,TUESDAY) will return 2011-12-13.<br>
* The input 2011-12-15 for (3,TUESDAY) will return 2011-12-20.<br>
* The input 2011-12-15 for (4,TUESDAY) will return 2011-12-27.<br>
* The input 2011-12-15 for (5,TUESDAY) will return 2012-01-03.<br>
* The input 2011-12-15 for (-1,TUESDAY) will return 2011-12-27 (last in month).<br>
* The input 2011-12-15 for (-4,TUESDAY) will return 2011-12-06 (3 weeks before last in month).<br>
* The input 2011-12-15 for (-5,TUESDAY) will return 2011-11-29 (4 weeks before last in month).<br>
* The input 2011-12-15 for (0,TUESDAY) will return 2011-11-29 (last in previous month).<br>
* <p>
* For a positive or zero ordinal, the algorithm is equivalent to finding the first
* day-of-week that matches within the month and then adding a number of weeks to it.
* For a negative ordinal, the algorithm is equivalent to finding the last
* day-of-week that matches within the month and then subtracting a number of weeks to it.
* The ordinal number of weeks is not validated and is interpreted leniently
* according to this algorithm. This definition means that an ordinal of zero finds
* the last matching day-of-week in the previous month.
* <p>
* The behavior is suitable for use with most calendar systems.
* It uses the {@code DAY_OF_WEEK} and {@code DAY_OF_MONTH} fields
* and the {@code DAYS} unit, and assumes a seven day week.
*
* @param ordinal the week within the month, unbounded but typically from -5 to 5
* @param dayOfWeek the day-of-week, not null
* @return the day-of-week in month adjuster, not null
*/
public static TemporalAdjuster dayOfWeekInMonth(int ordinal, DayOfWeek dayOfWeek) {
Jdk8Methods.requireNonNull(dayOfWeek, "dayOfWeek");
return new DayOfWeekInMonth(ordinal, dayOfWeek);
}
/**
* Class implementing day-of-week in month adjuster.
*/
private static final class DayOfWeekInMonth implements TemporalAdjuster {
/** The ordinal. */
private final int ordinal;
/** The day-of-week value, from 1 to 7. */
private final int dowValue;
private DayOfWeekInMonth(int ordinal, DayOfWeek dow) {
super();
this.ordinal = ordinal;
this.dowValue = dow.getValue();
}
@Override
public Temporal adjustInto(Temporal temporal) {
if (ordinal >= 0) {
Temporal temp = temporal.with(DAY_OF_MONTH, 1);
int curDow = temp.get(DAY_OF_WEEK);
long daysDiff = (dowValue - curDow + 7) % 7;
daysDiff += (ordinal - 1L) * 7L; // safe from overflow
return temp.plus(daysDiff, DAYS);
} else {
Temporal temp = temporal.with(DAY_OF_MONTH, temporal.range(DAY_OF_MONTH).getMaximum());
int curDow = temp.get(DAY_OF_WEEK);
long daysDiff = dowValue - curDow;
daysDiff = (daysDiff == 0 ? 0 : (daysDiff > 0 ? daysDiff - 7 : daysDiff));
daysDiff -= (-ordinal - 1L) * 7L; // safe from overflow
return temp.plus(daysDiff, DAYS);
}
}
}
//-----------------------------------------------------------------------
/**
* Returns the next day-of-week adjuster, which adjusts the date to the
* first occurrence of the specified day-of-week after the date being adjusted.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-17 (two days later).<br>
* The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-19 (four days later).<br>
* The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-22 (seven days later).
* <p>
* The behavior is suitable for use with most calendar systems.
* It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit,
* and assumes a seven day week.
*
* @param dayOfWeek the day-of-week to move the date to, not null
* @return the next day-of-week adjuster, not null
*/
public static TemporalAdjuster next(DayOfWeek dayOfWeek) {
return new RelativeDayOfWeek(2, dayOfWeek);
}
/**
* Returns the next-or-same day-of-week adjuster, which adjusts the date to the
* first occurrence of the specified day-of-week after the date being adjusted
* unless it is already on that day in which case the same object is returned.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-17 (two days later).<br>
* The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-19 (four days later).<br>
* The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-15 (same as input).
* <p>
* The behavior is suitable for use with most calendar systems.
* It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit,
* and assumes a seven day week.
*
* @param dayOfWeek the day-of-week to check for or move the date to, not null
* @return the next-or-same day-of-week adjuster, not null
*/
public static TemporalAdjuster nextOrSame(DayOfWeek dayOfWeek) {
return new RelativeDayOfWeek(0, dayOfWeek);
}
/**
* Returns the previous day-of-week adjuster, which adjusts the date to the
* first occurrence of the specified day-of-week before the date being adjusted.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-10 (five days earlier).<br>
* The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-12 (three days earlier).<br>
* The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-08 (seven days earlier).
* <p>
* The behavior is suitable for use with most calendar systems.
* It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit,
* and assumes a seven day week.
*
* @param dayOfWeek the day-of-week to move the date to, not null
* @return the previous day-of-week adjuster, not null
*/
public static TemporalAdjuster previous(DayOfWeek dayOfWeek) {
return new RelativeDayOfWeek(3, dayOfWeek);
}
/**
* Returns the previous-or-same day-of-week adjuster, which adjusts the date to the
* first occurrence of the specified day-of-week before the date being adjusted
* unless it is already on that day in which case the same object is returned.
* <p>
* The ISO calendar system behaves as follows:<br>
* The input 2011-01-15 (a Saturday) for parameter (MONDAY) will return 2011-01-10 (five days earlier).<br>
* The input 2011-01-15 (a Saturday) for parameter (WEDNESDAY) will return 2011-01-12 (three days earlier).<br>
* The input 2011-01-15 (a Saturday) for parameter (SATURDAY) will return 2011-01-15 (same as input).
* <p>
* The behavior is suitable for use with most calendar systems.
* It uses the {@code DAY_OF_WEEK} field and the {@code DAYS} unit,
* and assumes a seven day week.
*
* @param dayOfWeek the day-of-week to check for or move the date to, not null
* @return the previous-or-same day-of-week adjuster, not null
*/
public static TemporalAdjuster previousOrSame(DayOfWeek dayOfWeek) {
return new RelativeDayOfWeek(1, dayOfWeek);
}
/**
* Implementation of next, previous or current day-of-week.
*/
private static final class RelativeDayOfWeek implements TemporalAdjuster {
/** Whether the current date is a valid answer. */
private final int relative;
/** The day-of-week value, from 1 to 7. */
private final int dowValue;
private RelativeDayOfWeek(int relative, DayOfWeek dayOfWeek) {
Jdk8Methods.requireNonNull(dayOfWeek, "dayOfWeek");
this.relative = relative;
this.dowValue = dayOfWeek.getValue();
}
@Override
public Temporal adjustInto(Temporal temporal) {
int calDow = temporal.get(DAY_OF_WEEK);
if (relative < 2 && calDow == dowValue) {
return temporal;
}
if ((relative & 1) == 0) {
int daysDiff = calDow - dowValue;
return temporal.plus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS);
} else {
int daysDiff = dowValue - calDow;
return temporal.minus(daysDiff >= 0 ? 7 - daysDiff : -daysDiff, DAYS);
}
}
}
}