src/share/classes/java/time/temporal/TemporalAdjuster.java
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@@ -60,10 +60,13 @@
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package java.time.temporal;
import java.time.DateTimeException;
+import java.time.DayOfWeek;
+import java.time.LocalDate;
+import java.util.function.UnaryOperator;
/**
* Strategy for adjusting a temporal object.
* <p>
* Adjusters are a key tool for modifying temporal objects.
@@ -81,17 +84,26 @@
* temporal = temporal.with(thisAdjuster);
* </pre>
* It is recommended to use the second approach, {@code with(TemporalAdjuster)},
* as it is a lot clearer to read in code.
* <p>
- * See {@link Adjusters} for a standard set of adjusters, including finding the
- * last day of the month.
- * Adjusters may also be defined by applications.
+ * This class also contains a standard set of adjusters, available as static methods.
+ * These include:
+ * <ul>
+ * <li>finding the first or last day of the month
+ * <li>finding the first day of next month
+ * <li>finding the first or last day of the year
+ * <li>finding the first day of next year
+ * <li>finding the first or last day-of-week within a month, such as "first Wednesday in June"
+ * <li>finding the next or previous day-of-week, such as "next Thursday"
+ * </ul>
*
* <h3>Specification for implementors</h3>
* This interface places no restrictions on the mutability of implementations,
* however immutability is strongly recommended.
+ * <p>
+ * All the implementations supplied by the static methods on this interface are immutable.
*
* @since 1.8
*/
@FunctionalInterface
public interface TemporalAdjuster {
@@ -126,11 +138,11 @@
* Instead, an adjusted copy of the original must be returned.
* This provides equivalent, safe behavior for immutable and mutable temporal objects.
* <p>
* The input temporal object may be in a calendar system other than ISO.
* Implementations may choose to document compatibility with other calendar systems,
- * or reject non-ISO temporal objects by {@link Queries#chronology() querying the chronology}.
+ * or reject non-ISO temporal objects by {@link TemporalQuery#chronology() querying the chronology}.
* <p>
* This method may be called from multiple threads in parallel.
* It must be thread-safe when invoked.
*
* @param temporal the temporal object to adjust, not null
@@ -138,6 +150,313 @@
* @throws DateTimeException if unable to make the adjustment
* @throws ArithmeticException if numeric overflow occurs
*/
Temporal adjustInto(Temporal temporal);
+ //-----------------------------------------------------------------------
+ /**
+ * Obtains a {@code TemporalAdjuster} that wraps a date adjuster.
+ * <p>
+ * The {@code TemporalAdjuster} is based on the low level {@code Temporal} interface.
+ * This method allows an adjustment from {@code LocalDate} to {@code LocalDate}
+ * to be wrapped to match the temporal-based interface.
+ * This is provided for convenience to make user-written adjusters simpler.
+ * <p>
+ * In general, user-written adjusters should be static constants:
+ * <pre>
+ * static TemporalAdjuster TWO_DAYS_LATER = TemporalAdjuster.ofDateAdjuster(
+ * date -> date.plusDays(2));
+ * </pre>
+ *
+ * @param dateBasedAdjuster the date-based adjuster, not null
+ * @return the temporal adjuster wrapping on the date adjuster, not null
+ */
+ static TemporalAdjuster ofDateAdjuster(UnaryOperator<LocalDate> dateBasedAdjuster) {
+ return TemporalAdjusters.ofDateAdjuster(dateBasedAdjuster);
+ }
+
+ //-----------------------------------------------------------------------
+ /**
+ * 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
+ */
+ static TemporalAdjuster firstDayOfMonth() {
+ return TemporalAdjusters.firstDayOfMonth();
+ }
+
+ /**
+ * 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
+ */
+ static TemporalAdjuster lastDayOfMonth() {
+ return TemporalAdjusters.lastDayOfMonth();
+ }
+
+ /**
+ * 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
+ */
+ static TemporalAdjuster firstDayOfNextMonth() {
+ return TemporalAdjusters.firstDayOfNextMonth();
+ }
+
+ //-----------------------------------------------------------------------
+ /**
+ * 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
+ */
+ static TemporalAdjuster firstDayOfYear() {
+ return TemporalAdjusters.firstDayOfYear();
+ }
+
+ /**
+ * 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
+ */
+ static TemporalAdjuster lastDayOfYear() {
+ return TemporalAdjusters.lastDayOfYear();
+ }
+
+ /**
+ * 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
+ */
+ static TemporalAdjuster firstDayOfNextYear() {
+ return TemporalAdjusters.firstDayOfNextYear();
+ }
+
+ //-----------------------------------------------------------------------
+ /**
+ * 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
+ */
+ static TemporalAdjuster firstInMonth(DayOfWeek dayOfWeek) {
+ return TemporalAdjuster.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
+ */
+ static TemporalAdjuster lastInMonth(DayOfWeek dayOfWeek) {
+ return TemporalAdjuster.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
+ */
+ static TemporalAdjuster dayOfWeekInMonth(final int ordinal, DayOfWeek dayOfWeek) {
+ return TemporalAdjusters.dayOfWeekInMonth(ordinal, dayOfWeek);
+ }
+
+ //-----------------------------------------------------------------------
+ /**
+ * 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
+ */
+ static TemporalAdjuster next(DayOfWeek dayOfWeek) {
+ return TemporalAdjusters.next(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
+ */
+ static TemporalAdjuster nextOrSame(DayOfWeek dayOfWeek) {
+ return TemporalAdjusters.nextOrSame(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
+ */
+ static TemporalAdjuster previous(DayOfWeek dayOfWeek) {
+ return TemporalAdjusters.previous(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
+ */
+ static TemporalAdjuster previousOrSame(DayOfWeek dayOfWeek) {
+ return TemporalAdjusters.previousOrSame(dayOfWeek);
+ }
+
}