Java TemporalAdjuster Tutorial with Examples

TemporalAdjuster
Basic Examples
Custom TemporalAdjuster Examples
TemporalAdjusters Examples

1. TemporalAdjuster

No ADS

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:

IsoEra
MinguoEra
LocalDateTime
LocalTime
ZoneOffset
HijrahEra
MonthDay
Month
DayOfWeek
LocalDate
JapaneseEra
YearMonth
OffsetTime
Instant
Era
Year
OffsetDateTime
ThaiBuddhistEra
ChronoLocalDate
ThaiBuddhistDate
MinguoDate
JapaneseDate
HijrahDate
ChronoLocalDateTime
TemporalAdjusters

There are two ways to adjust a Temporal object, in which 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)

2. Basic Examples

No ADS

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

OffsetDateTime
ZonedDateTime
LocalDate

3. Custom TemporalAdjuster Examples

No ADS

Assume that the working days of the week are from Monday to 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
Temporal
ZonedDateTime
DayOfWeek

4. TemporalAdjusters Examples

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".

Java TemporalAdjusters

No ADS

Java TemporalAdjuster Tutorial with Examples

1. TemporalAdjuster

2. Basic Examples

3. Custom TemporalAdjuster Examples

4. TemporalAdjusters Examples

Java Date Time Tutorials

Java Date Time Tutorials

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