Java TemporalAdjuster Tutorial
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The TemporalAdjuster interface is a tool for adjusting a Temporal object to create a copy. Basically, TemporalAdjuster exists to externalize a process of adjusting Temporal objects rather than adjusting them directly.
@FunctionalInterface
public interface TemporalAdjuster {
Temporal adjustInto(Temporal temporal);
}
Example: We create TruncateTimeAdjuster class to truncate the time (hours, minutes, seconds, nanoseconds) of a Temporal object.
| Temporal | Example | Apply TruncateTimeAdjuster |
| LocalDateTime | 2020-11-25 13:30:45 | 2020-11-25 00:00:00 |
| ZonedDateTime | 2020-11-25 13:30:45+06:00[Asia/Bishkek] | 2020-11-25 00:00:00+06:00[Asia/Bishkek] |
| LocalTime | 13:30:45 | 00:00:00 |
TruncateTimeAdjuster.java
package org.o7planning.temporaladjuster.ex;
import java.time.temporal.ChronoField;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAdjuster;
public class TruncateTimeAdjuster implements TemporalAdjuster {
@Override
public Temporal adjustInto(Temporal temporal) {
Temporal adjustedTemporal = temporal;
if (temporal.isSupported(ChronoField.HOUR_OF_DAY)) {
adjustedTemporal = adjustedTemporal.with(ChronoField.HOUR_OF_DAY, 0);
}
if (temporal.isSupported(ChronoField.MINUTE_OF_HOUR)) {
adjustedTemporal = adjustedTemporal.with(ChronoField.MINUTE_OF_HOUR, 0);
}
if (temporal.isSupported(ChronoField.SECOND_OF_MINUTE)) {
adjustedTemporal = adjustedTemporal.with(ChronoField.SECOND_OF_MINUTE, 0);
}
if (temporal.isSupported(ChronoField.NANO_OF_SECOND)) {
adjustedTemporal = adjustedTemporal.with(ChronoField.NANO_OF_SECOND, 0);
}
return adjustedTemporal;
}
}
Using TruncateTemporalAdjuster:
TruncateTimeAdjuster_ex1.java
TruncateTimeAdjuster truncateTimeAdjuster = new TruncateTimeAdjuster();
// Create a Temporal object from LocalDateTime
LocalDateTime localDateTime = LocalDateTime.now();
LocalDateTime adjustedLocalDateTime = (LocalDateTime) truncateTimeAdjuster.adjustInto(localDateTime);
System.out.printf("localDateTime: %s%n", localDateTime);
System.out.printf("adjustedLocalDateTime: %s%n%n", adjustedLocalDateTime);
// Create a Temporal object from ZonedDateTime
ZonedDateTime zonedDateTime = ZonedDateTime.now();
ZonedDateTime adjustedZonedDateTime = (ZonedDateTime) truncateTimeAdjuster.adjustInto(zonedDateTime);
System.out.printf("zonedDateTime: %s%n", zonedDateTime);
System.out.printf("adjustedZonedDateTime: %s%n%n", adjustedZonedDateTime);
// Create a Temporal object from OffsetDateTime
OffsetDateTime offsetDateTime = OffsetDateTime.now();
OffsetDateTime adjustedOffsetDateTime = (OffsetDateTime) truncateTimeAdjuster.adjustInto(offsetDateTime);
System.out.printf("offsetDateTime: %s%n", offsetDateTime);
System.out.printf("adjustedOffsetDateTime: %s%n", adjustedOffsetDateTime);
Output:
localDateTime: 2021-07-05T00:30:09.309188 adjustedLocalDateTime: 2021-07-05T00:00 zonedDateTime: 2021-07-05T00:30:09.322306+06:00[Asia/Bishkek] adjustedZonedDateTime: 2021-07-05T00:00+06:00[Asia/Bishkek] offsetDateTime: 2021-07-05T00:30:09.323143+06:00 adjustedOffsetDateTime: 2021-07-05T00:00+06:00
There are many classes in the Java Date Time API that implement the TemporalAdjuster interface, which means they are capable of adjusting other Temporal objects:
- ChronoLocalDate
- ChronoLocalDateTime
- DayOfWeek
- Era
- HijrahDate
- HijrahEra
- Instant
- IsoEra
- JapaneseDate
- JapaneseEra
- LocalDate
- LocalDateTime
- LocalTime
- MinguoDate
- MinguoEra
- Month
- MonthDay
- OffsetDateTime
- OffsetTime
- TemporalAdjusters
- ThaiBuddhistDate
- ThaiBuddhistEra
- Year
- YearMonth
- ZoneOffset
There are two ways to adjust a Temporal object, the second approach is recommended.
// these two lines are equivalent, but the second approach is recommended adjustedTemporal = thisAdjuster.adjustInto(temporal); // (1) adjustedTemporal = temporal.with(thisAdjuster); // (2)
Example: Adjust all given Temporal objects to May 2000, other fields remain unchanged.
TemporalAdjuster_ex1.java
package org.o7planning.temporaladjuster.ex;
import java.time.LocalDate;
import java.time.YearMonth;
import java.time.ZonedDateTime;
import java.time.temporal.TemporalAdjuster;
public class TemporalAdjuster_ex1 {
public static void main(String[] args) {
TemporalAdjuster adjuster = YearMonth.of(2020, 5); // May 2020.
// Create a Temporal object from ZonedDateTime
ZonedDateTime zonedDateTime = ZonedDateTime.now();
ZonedDateTime adjustedZonedDateTime = (ZonedDateTime) adjuster.adjustInto(zonedDateTime);
System.out.printf("zonedDateTime: %s%n", zonedDateTime);
System.out.printf("adjustedZonedDateTime: %s%n%n", adjustedZonedDateTime);
// Create a Temporal object from LocalDate
LocalDate localDate = LocalDate.now();
LocalDate adjustedLocalDate = (LocalDate) adjuster.adjustInto(localDate);
System.out.printf("localDate: %s%n", localDate);
System.out.printf("adjustedLocalDate: %s%n", adjustedLocalDate);
}
}
Output:
zonedDateTime: 2021-07-05T00:51:07.837210+06:00[Asia/Bishkek] adjustedZonedDateTime: 2020-05-05T00:51:07.837210+06:00[Asia/Bishkek] localDate: 2021-07-05 adjustedLocalDate: 2020-05-05
Example: Adjust the zone-offset for the given OffsetDateTime objects to +15;
TemporalAdjuster_ex2.java
TemporalAdjuster adjuster = ZoneOffset.ofHours(15);
// Create a Temporal object from OffsetDateTime
OffsetDateTime offsetDateTime1 = OffsetDateTime.now();
OffsetDateTime adjustedOffsetDateTime1 = (OffsetDateTime) adjuster.adjustInto(offsetDateTime1);
System.out.printf("offsetDateTime1: %s%n", offsetDateTime1);
System.out.printf("adjustedOffsetDateTime1: %s%n%n", adjustedOffsetDateTime1);
// Create a Temporal object from OffsetDateTime
OffsetDateTime offsetDateTime2 = OffsetDateTime.parse("2000-01-01T01:00+01:00");
OffsetDateTime adjustedOffsetDateTime2 = (OffsetDateTime) adjuster.adjustInto(offsetDateTime2);
System.out.printf("offsetDateTime2: %s%n", offsetDateTime2);
System.out.printf("adjustedOffsetDateTime2: %s%n%n", adjustedOffsetDateTime2);
Output:
offsetDateTime1: 2021-07-05T01:15:48.372665+06:00 adjustedOffsetDateTime1: 2021-07-05T01:15:48.372665+15:00 offsetDateTime2: 2000-01-01T01:00+01:00 adjustedOffsetDateTime2: 2000-01-01T01:00+15:00
- LocalDate
- OffsetDateTime
- ZonedDateTime
Assume that the working days of the week are Monday through Friday. We write NextWorkingDayAdjuster class to find the next working day after the given date.
NextWorkingDayAdjuster.java
package org.o7planning.temporaladjuster.ex;
import java.time.DayOfWeek;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAdjuster;
public class NextWorkingDayAdjuster implements TemporalAdjuster {
@Override
public Temporal adjustInto(Temporal temporal) {
int field = temporal.get(ChronoField.DAY_OF_WEEK);
DayOfWeek dayOfWeek = DayOfWeek.of(field);
int daysToAdd = 1;
if (DayOfWeek.FRIDAY.equals(dayOfWeek)) {
daysToAdd = 3;
} else if (DayOfWeek.SATURDAY.equals(dayOfWeek)) {
daysToAdd = 2;
}
return temporal.plus(daysToAdd, ChronoUnit.DAYS);
}
}
For example, using the NextWorkingDayAdjuster class:
NextWorkingDayAdjuster_ex1.java
package org.o7planning.temporaladjuster.ex;
import java.time.LocalDate;
import java.time.ZonedDateTime;
import java.time.temporal.TemporalAdjuster;
public class NextWorkingDayAdjuster_ex1 {
public static void main(String[] args) {
TemporalAdjuster adjuster = new NextWorkingDayAdjuster();
// Create a Temporal object from LocalDate
LocalDate localDate = LocalDate.now();
LocalDate nextWorkingDay = (LocalDate) adjuster.adjustInto(localDate);
System.out.printf("localDate: %s%n", localDate);
System.out.printf("nextWorkingDay: %s%n", nextWorkingDay);
System.out.println(" ----- ");
// Create a Temporal object from ZonedDateTime
ZonedDateTime zonedDateTime = ZonedDateTime.now();
ZonedDateTime adjustedZonedDateTime = (ZonedDateTime) adjuster.adjustInto(zonedDateTime);
nextWorkingDay = adjustedZonedDateTime.toLocalDate();
System.out.printf("zonedDateTime: %s%n", zonedDateTime);
System.out.printf("adjustedZonedDateTime: %s%n", adjustedZonedDateTime);
System.out.printf("nextWorkingDay: %s%n", nextWorkingDay);
}
}
Output:
localDate: 2021-07-05 nextWorkingDay: 2021-07-06 ----- zonedDateTime: 2021-07-05T01:34:09.112648+06:00[Asia/Bishkek] adjustedZonedDateTime: 2021-07-06T01:34:09.112648+06:00[Asia/Bishkek] nextWorkingDay: 2021-07-06
Example: Write the NextChristmasAdjuster class to find the next christmas date:
NextChristmasAdjuster.java
package org.o7planning.temporaladjuster.ex;
import java.time.Period;
import java.time.temporal.ChronoField;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAdjuster;
public class NextChristmasAdjuster implements TemporalAdjuster {
@Override
public Temporal adjustInto(Temporal temporal) {
int month = temporal.get(ChronoField.MONTH_OF_YEAR);
int day = temporal.get(ChronoField.DAY_OF_MONTH);
if(month == 12 && day > 25) {
temporal = temporal.plus(Period.ofYears(1));
}
return temporal.with(ChronoField.MONTH_OF_YEAR, 12).with(ChronoField.DAY_OF_MONTH, 25);
}
}
Using the NextChristmasAdjuster class:
NextChristmasAdjuster_ex1.java
package org.o7planning.temporaladjuster.ex;
import java.time.LocalDate;
import java.time.temporal.TemporalAdjuster;
public class NextChristmasAdjuster_ex1 {
public static void main(String[] args) {
TemporalAdjuster adjuster = new NextChristmasAdjuster();
// Create a Temporal object from LocalDate
LocalDate localDate1 = LocalDate.of(2021, 7, 5);
LocalDate nextChristmasDay = (LocalDate) adjuster.adjustInto(localDate1);
System.out.printf("localDate1: %s%n", localDate1);
System.out.printf("nextChristmasDay: %s%n", nextChristmasDay);
System.out.println(" ----- ");
// Create a Temporal object from LocalDate
LocalDate localDate2 = LocalDate.of(2021, 12, 26);
nextChristmasDay = (LocalDate) adjuster.adjustInto(localDate2);
System.out.printf("localDate2: %s%n", localDate2);
System.out.printf("nextChristmasDay: %s%n", nextChristmasDay);
}
}
Output:
localDate1: 2021-07-05 nextChristmasDay: 2021-12-25 ----- localDate2: 2021-12-26 nextChristmasDay: 2022-12-25
- ChronoField
- DayOfWeek
- Temporal
- ZonedDateTime
The TemporalAdjusters class provides static methods to obtain standard TemporalAdjuster(s). These include:
- Finding the first or last day of the month.
- Finding the first day of next month.
- Finding the first or last day of the year.
- Finding the first day of next year.
- Finding the first or last "day-of-week" within a month, such as "first Wednesday in June".
- Finding the next or previous "day-of-week", such as "next Thursday".
