1. Introduction
Java 8 Date-Time API is a JSR-310 implementation. It has a new set of packages to provide a comprehensive date-time model.
- java.time – base package for managing dates and times
- java.time.chrono – handles alternative calendaring and chronology systems
- java.time.format – handles formatting of dates and times
- java.time.temporal – accesses to date and time using fields, units, and adjusters
Java 8 Temporal is an interface which defines read-write access to a temporal object, such as the date, time, offset or a combination of these. Java 8 provides many common implementation classes: LocalDate, LocalTime, LocalDateTime, ZonedDateTime, Instant, JapaneseDate, ThaiBuddhistDate, HijrahDate, MinguoDate, etc.
Java 8 TemporalAdjusters is a class which contains predefined static implementations for many common useful methods to modify temporal objects.
| Method Name | Description |
|---|---|
firstDayOfMonth | Returns the “first day of month” adjuster, which returns a new date set it to the first day of the current month. |
lastDayOfMonth | Returns the “last day of month” adjuster, which returns a new date set it to the last day of the current month. |
firstDayOfNextMonth | Returns the “first day of next month” adjuster, which returns a new date set it to the first day of the next month. |
firstDayOfYear | Returns the “first day of the year” adjuster, which returns a new date set it to the first day of the current year. |
lastDayOfYear | Returns the “last day of the year” adjuster, which returns a new date set it to the last day of the current year. |
firstDayOfNextYear | Returns the “first day of next year” adjuster, which returns a new date set it to the first day of the next year. |
firstInMonth | Returns the “first day-of-week within a month” adjuster, which returns a new date in the same month with the first matching day-of-week. Such as “first Wednesday in June”. |
lastInMonth | Returns the “last day-of-week within a month adjuster”, such as “last Thursday in November” |
dayOfWeekInMonth | Returns the “day-of-week in month” adjuster, which returns a new date in the same month with the ordinal day-of-week. |
next | 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. |
previous | 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. |
In this example, I will demonstrate how to adjust the date in LocalDate, LocalDateTime, ZonedDateTime, JapaneseDate, ThaiBuddhistDate, HijrahDate, MinguoDate using TemporalAdjusters.
2. Technologies used
The example code in this article was built and run using:
- Java 1.8.101
- Maven 3.3.9
- Eclipse Oxygen
- JUnit 4.12
3. Maven Project
3.1 Dependency
Add JUnit to the pom.xml.
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>zheng.jcg.demo</groupId> <artifactId>java8-demo</artifactId> <version>0.0.1-SNAPSHOT</version> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <artifactId>maven-compiler-plugin</artifactId> <version>3.3</version> <configuration> <source>1.8</source> <target>1.8</target> </configuration> </plugin> </plugins> </build> </project>
4. Custom TemporalAdjuster
4.1 HolidayAdjuster
If you work on a system which needs to find holidays like Mother’s Day, Father’s Day, Labor Day, or Thanksgiving, you can do so with TemporalAdjusters.dayOfWeekInMonth in a few lines of codes. In this step, I will create a HolidayAdjuster class to find a holiday as a LocalDate.
HolidayAdjuster.java
package com.zheng.demo;
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.Month;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAdjusters;
public class HolidayAdjuster implements TemporalAdjuster {
private static final int FIRST_DAY = 1;
public HolidayAdjuster(Month month, int ordinal, DayOfWeek dayOfWeek) {
super();
this.month = month;
this.dayOfWeek = dayOfWeek;
this.ordinal = ordinal;
}
private Month month;
private DayOfWeek dayOfWeek;
private int ordinal;
@Override
public Temporal adjustInto(Temporal temporalAdjusterInput) {
LocalDate temporalAdjusterDate = LocalDate.from(temporalAdjusterInput);
LocalDate holidayMonth = LocalDate.of(temporalAdjusterDate.getYear(), month, FIRST_DAY);
return holidayMonth.with(TemporalAdjusters.dayOfWeekInMonth(ordinal, dayOfWeek));
}
}
4.2 HolidayAdjusterTest
In this step, I will create four unit test cases to output the date for Mother’s day, Father’s Day, Labor Day, and Thanksgiving. Please note that the Temporal must be a LocalDate type.
HolidayAdjusterTest.java
package com.zheng.demo;
import java.time.DateTimeException;
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.LocalTime;
import java.time.Month;
import org.junit.Before;
import org.junit.Test;
public class HolidayAdjusterTest {
private LocalDate localDate;
@Before
public void setup() {
localDate = LocalDate.now();
System.out.print("\nCurrent localDate : " + localDate + ". ");
}
@Test
public void mothersDay_customerAdjuster() {
HolidayAdjuster mothersDayAdjuster = new HolidayAdjuster(Month.MAY, 2, DayOfWeek.SUNDAY);
LocalDate mothersDay = localDate.with(mothersDayAdjuster);
System.out.println("Mother's Day : " + mothersDay);
}
@Test
public void fathersDay_customerAdjuster() {
HolidayAdjuster fathersDayAdjuster = new HolidayAdjuster(Month.JUNE, 3, DayOfWeek.SUNDAY);
LocalDate fathersDay = localDate.with(fathersDayAdjuster);
System.out.println("Father's Day : " + fathersDay);
}
@Test
public void laborDay_customerAdjuster() {
HolidayAdjuster laborDayAdjuster = new HolidayAdjuster(Month.SEPTEMBER, 1, DayOfWeek.MONDAY);
LocalDate laborDay = localDate.with(laborDayAdjuster);
System.out.println("Labor Day : " + laborDay);
}
@Test
public void thanksGivingDate_customAdjuster() {
HolidayAdjuster thanksgivingAdjuster = new HolidayAdjuster(Month.NOVEMBER, 4, DayOfWeek.THURSDAY);
LocalDate thanksGivingDay = localDate.with(thanksgivingAdjuster);
System.out.println("Thanksgiving Date: " + thanksGivingDay);
}
@Test(expected=DateTimeException.class)
public void exception_wrongtype() {
LocalTime test = LocalTime.now();
System.out.println("Throw Exception if not LocalDate.");
test.with(new HolidayAdjuster(Month.NOVEMBER, 4,
DayOfWeek.THURSDAY));
}
}
Execute HolidayAdjusterTest as Junit test and capture the output here.
Junit Output
Current localDate : 2018-11-28. Labor Day : 2018-09-03 Current localDate : 2018-11-28. Father's Day : 2018-06-17 Current localDate : 2018-11-28. Thanksgiving Date: 2018-11-22 Current localDate : 2018-11-28. Throw Exception if not LocalDate. Current localDate : 2018-11-28. Mother's Day : 2018-05-13
4.3 PaydayAdjuster
Company A schedules to cut the paycheck at 10 AM twice a month, one is on the 15th day of every month, the other is on the last day of every month. If it is on a Saturday or Sunday, then it is set to Friday. In this step, I will create a PayDayAdjuster class to find the next payday as a LocalDateTime with the previous and lastDayOfMonth methods.
PaydayAdjuster.java
package com.zheng.demo;
import java.time.DayOfWeek;
import java.time.LocalDateTime;
import java.time.temporal.Temporal;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAdjusters;
public class PaydayAdjuster implements TemporalAdjuster {
private static final int TEN_OCLOCK = 10;
private static final int MID_MONTH_DAY = 15;
public PaydayAdjuster() {
super();
}
@Override
public Temporal adjustInto(Temporal temporalAdjusterInput) {
LocalDateTime orgDate = LocalDateTime.from(temporalAdjusterInput);
LocalDateTime date = LocalDateTime.of(orgDate.getYear(), orgDate.getMonth(), orgDate.getDayOfMonth(),
TEN_OCLOCK, 0);
int day;
if (date.getDayOfMonth() < MID_MONTH_DAY) {
day = MID_MONTH_DAY;
} else {
day = date.with(TemporalAdjusters.lastDayOfMonth()).getDayOfMonth();
}
date = date.withDayOfMonth(day);
if (date.getDayOfWeek() == DayOfWeek.SATURDAY || date.getDayOfWeek() == DayOfWeek.SUNDAY) {
date = date.with(TemporalAdjusters.previous(DayOfWeek.FRIDAY));
}
return temporalAdjusterInput.with(date);
}
}
4.4 PaydayAdjusterTest
In this step, I will create unit test cases to output the next payday. Please note that Temporal must be a LocalDateTime type.
PaydayAdjusterTest.java
package com.zheng.demo;
import java.time.DateTimeException;
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.Month;
import java.time.temporal.TemporalAdjusters;
import org.junit.Before;
import org.junit.Test;
public class PaydayAdjusterTest {
private LocalDateTime localDate;
@Before
public void setup() {
localDate = LocalDateTime.now();
System.out.print("\nCurrent LocalDateTime : " + localDate + ". ");
}
@Test
public void nextPayDay() {
LocalDateTime payDate = localDate.with(new PaydayAdjuster());
System.out.println("Next Pay Day : " + payDate);
}
@Test
public void nextMonthPayDay() {
LocalDateTime firstMonth = localDate.with(TemporalAdjusters.firstDayOfNextMonth());
LocalDateTime payDate = firstMonth.with(new PaydayAdjuster());
System.out.println("Next Month Pay Day : " + payDate);
}
@Test(expected = DateTimeException.class)
public void exception_wrongtype() {
LocalDate test = LocalDate.now();
System.out.println("Throw Exception if not LocalDateTime.");
test.with(new HolidayAdjuster(Month.NOVEMBER, 4, DayOfWeek.THURSDAY));
}
}
Execute it as Junit test and capture the output.
PaydayAdjusterTest Output
Current LocalDateTime : 2018-11-28T08:55:55.887. Next Month Pay Day : 2018-12-14T10:00 Current LocalDateTime : 2018-11-28T08:55:55.950. Next Pay Day : 2018-11-30T10:00 Current LocalDateTime : 2018-11-28T08:55:55.950. Throw Exception if not LocalDateTime.
5. JUnit Tests
Java 8 TemporalAdjusters provides lots of out-of-box solutions for adjusting the date. In this step, I will create JUnit tests to demonstrate how to use these pre-defined static methods to modify temporal objects.
5.1 TemporalAdjusters_LocalDateTest
Java 8 LocalDate represents a date without a time zone or time. In this step, I will adjust the year, month, and day with the pre-defined methods: firstDayOfYear, firstDayOfMonth, etc.
TemporalAdjusters_LocalDateTest.java
package com.zheng.demo;
import static org.junit.Assert.assertEquals;
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAdjusters;
import org.junit.Before;
import org.junit.Test;
public class TemporalAdjusters_LocalDateTest {
private LocalDate localDate;
@Before
public void setup() {
localDate = LocalDate.now();
System.out.println("\nCurrent localDate : " + localDate);
}
@Test
public void adjuster_firstDayOfMonth() {
LocalDate updatedDate = localDate.with(TemporalAdjusters.firstDayOfMonth());
System.out.println("firstDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_firstDayOfYear() {
LocalDate updatedDate = localDate.with(TemporalAdjusters.firstDayOfYear());
System.out.println("firstDayOfYear : " + updatedDate);
}
@Test
public void adjuster_lastDayOfYear() {
LocalDate updatedDate = localDate.with(TemporalAdjusters.lastDayOfYear());
System.out.println("lastDayOfYear : " + updatedDate);
}
@Test
public void adjuster_firstDayOfNextYear() {
LocalDate updatedDate = localDate.with(TemporalAdjusters.firstDayOfNextYear());
System.out.println("firstDayOfNextYear : " + updatedDate);
}
@Test
public void adjuster_firstDayOfNextMonth() {
LocalDate updatedDate = localDate.with(TemporalAdjusters.firstDayOfNextMonth());
System.out.println("firstDayOfNextMonth : " + updatedDate);
}
@Test
public void adjuster_lastDayOfMonth() {
LocalDate updatedDate = localDate.with(TemporalAdjusters.lastDayOfMonth());
System.out.println("lastDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_nextMonday() {
LocalDate updatedDate = localDate.with(TemporalAdjusters.next(DayOfWeek.MONDAY));
System.out.println("nextMonday : " + updatedDate);
}
@Test
public void adjuster_nextSunday() {
LocalDate localDate = LocalDate.of(2018, 11, 10);
LocalDate nextSunday = localDate.with(TemporalAdjusters.next(DayOfWeek.SUNDAY));
assertEquals("2018-11-11", nextSunday.toString());
}
@Test
public void adjuster_firstInMonth() {
LocalDate updatedDate = localDate.with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY));
System.out.println("firstInMonth_Monday: " + updatedDate);
}
@Test
public void adjuster_previousWednesday() {
LocalDate updatedDate = localDate.with(TemporalAdjusters.previous(DayOfWeek.WEDNESDAY));
System.out.println("previousWednesday : " + updatedDate);
}
@Test
public void christmasDay_customAdjuster() {
TemporalAdjuster xmas = temporal -> temporal.with(ChronoField.MONTH_OF_YEAR, 12).with(ChronoField.DAY_OF_MONTH,
25);
LocalDate xmasDate = localDate.with(xmas);
System.out.println("Christmas : " + xmasDate + ", it's on " + xmasDate.getDayOfWeek());
}
@Test
public void tenDaysLater() {
TemporalAdjuster tenDaysFromNow = temporal -> temporal.plus(10, ChronoUnit.DAYS);
LocalDate localTimeUpdate = localDate.with(tenDaysFromNow);
System.out.println("Ten Days later : " + localTimeUpdate);
}
}5.2 TemporalAdjusters_LocalDateTimeTest
Java 8 LocalDateTime represents a date without a time zone. I will repeat the same adjustment for the LocalDateTime type.
TemporalAdjusters_LocalDateTimeTest.java
package com.zheng.demo;
import java.time.DayOfWeek;
import java.time.Duration;
import java.time.LocalDateTime;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAdjusters;
import org.junit.Before;
import org.junit.Test;
public class TemporalAdjusters_LocalDateTimeTest {
private LocalDateTime localDateTime;
@Before
public void setup() {
localDateTime = LocalDateTime.now();
System.out.println("\nCurrent LocalDateTime : " + localDateTime);
}
@Test
public void adjuster_firstDayOfMonth() {
LocalDateTime updatedDate = localDateTime.with(TemporalAdjusters.firstDayOfMonth());
System.out.println("firstDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_firstDayOfNextMonth() {
LocalDateTime updatedDate = localDateTime.with(TemporalAdjusters.firstDayOfNextMonth());
System.out.println("firstDayOfNextMonth : " + updatedDate);
}
@Test
public void adjuster_lastDayOfMonth() {
LocalDateTime updatedDate = localDateTime.with(TemporalAdjusters.lastDayOfMonth());
System.out.println("lastDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_nextMonday() {
LocalDateTime updatedDate = localDateTime.with(TemporalAdjusters.next(DayOfWeek.MONDAY));
System.out.println("Next Monday : " + updatedDate);
}
@Test
public void adjuster_previousWednesday() {
LocalDateTime updatedDate = localDateTime.with(TemporalAdjusters.previous(DayOfWeek.WEDNESDAY));
System.out.println("Previous Wednesday : " + updatedDate);
}
@Test
public void christmasDay() {
TemporalAdjuster xmas = temporal -> temporal.with(ChronoField.MONTH_OF_YEAR, 12).with(ChronoField.DAY_OF_MONTH,
25);
LocalDateTime xmasDate = localDateTime.with(xmas);
System.out.println("Christmas : " + xmasDate + ", it's on " + xmasDate.getDayOfWeek());
}
@Test
public void tenDaysThreeHourLater() {
TemporalAdjuster tenDaysThreeHoursFromNow = temporal -> temporal.plus(10, ChronoUnit.DAYS)
.plus(Duration.ofHours(3));
LocalDateTime localTimeUpdate = localDateTime.with(tenDaysThreeHoursFromNow);
System.out.println("Ten Days later : " + localTimeUpdate);
}
}5.3 TemporalAdjusters_ZonedDateTimeTest
Java 8 ZonedDateTime represents a date with a time zone. In this step, I will repeat the same adjustment for the ZonedDateTime class.
TemporalAdjusters_ZonedDateTimeTest.java
package com.zheng.demo;
import java.time.DayOfWeek;
import java.time.ZonedDateTime;
import java.time.temporal.ChronoField;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAdjusters;
import org.junit.Before;
import org.junit.Test;
public class TemporalAdjusters_ZonedDateTimeTest {
private ZonedDateTime zonedDateTime;
@Before
public void setup() {
zonedDateTime = ZonedDateTime.now();
System.out.println("\nCurrent ZonedDateTime : " + zonedDateTime);
}
@Test
public void adjuster_firstDayOfMonth() {
ZonedDateTime updatedDate = zonedDateTime.with(TemporalAdjusters.firstDayOfMonth());
System.out.println("firstDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_firstDayOfYear() {
ZonedDateTime updatedDate = zonedDateTime.with(TemporalAdjusters.firstDayOfYear());
System.out.println("firstDayOfYear : " + updatedDate);
}
@Test
public void adjuster_lastDayOfYear() {
ZonedDateTime updatedDate = zonedDateTime.with(TemporalAdjusters.lastDayOfYear());
System.out.println("lastDayOfYear : " + updatedDate);
}
@Test
public void adjuster_firstDayOfNextYear() {
ZonedDateTime updatedDate = zonedDateTime.with(TemporalAdjusters.firstDayOfNextYear());
System.out.println("firstDayOfNextYear : " + updatedDate);
}
@Test
public void adjuster_firstDayOfNextMonth() {
ZonedDateTime updatedDate = zonedDateTime.with(TemporalAdjusters.firstDayOfNextMonth());
System.out.println("firstDayOfNextMonth : " + updatedDate);
}
@Test
public void adjuster_lastDayOfMonth() {
ZonedDateTime updatedDate = zonedDateTime.with(TemporalAdjusters.lastDayOfMonth());
System.out.println("lastDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_nextMonday() {
ZonedDateTime updatedDate = zonedDateTime.with(TemporalAdjusters.next(DayOfWeek.MONDAY));
System.out.println("nextMonday : " + updatedDate);
}
@Test
public void adjuster_firstInMonth() {
ZonedDateTime updatedDate = zonedDateTime.with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY));
System.out.println("firstInMonth_Monday: " + updatedDate);
}
@Test
public void adjuster_previousWednesday() {
ZonedDateTime updatedDate = zonedDateTime.with(TemporalAdjusters.previous(DayOfWeek.WEDNESDAY));
System.out.println("previousWednesday : " + updatedDate);
}
@Test
public void christmasDay() {
TemporalAdjuster xmas = temporal -> temporal.with(ChronoField.MONTH_OF_YEAR, 12).with(ChronoField.DAY_OF_MONTH,
25);
ZonedDateTime xmasDate = zonedDateTime.with(xmas);
System.out.println("Christmas : " + xmasDate + ", it's on " + xmasDate.getDayOfWeek());
}
@Test
public void tenDaysLater() {
TemporalAdjuster tenDaysFromNow = temporal -> temporal.plus(10, ChronoUnit.DAYS);
ZonedDateTime localTimeUpdate = zonedDateTime.with(tenDaysFromNow);
System.out.println("Ten Days later : " + localTimeUpdate);
}
}5.4 TemporalAdjusters_MinguoDateTest
Java 8 MinGuoDate represents a date in the Minguo calendar system. It is primarily used in the Republic of China, often known as Taiwan. I will repeat the same adjustment for the MinGuoDate class.
TemporalAdjusters_MinguoDateTest.java
package com.zheng.demo;
import java.time.DayOfWeek;
import java.time.chrono.MinguoDate;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAdjusters;
import org.junit.Before;
import org.junit.Test;
public class TemporalAdjusters_MinguoDateTest {
private MinguoDate minguoDate;
@Before
public void setup() {
minguoDate = MinguoDate.now();
System.out.println("\nCurrent MinguoDate : " + minguoDate);
}
@Test
public void adjuster_firstDayOfMonth() {
MinguoDate updatedDate = minguoDate.with(TemporalAdjusters.firstDayOfMonth());
System.out.println("firstDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_firstDayOfYear() {
MinguoDate updatedDate = minguoDate.with(TemporalAdjusters.firstDayOfYear());
System.out.println("firstDayOfYear : " + updatedDate);
}
@Test
public void adjuster_lastDayOfYear() {
MinguoDate updatedDate = minguoDate.with(TemporalAdjusters.lastDayOfYear());
System.out.println("lastDayOfYear : " + updatedDate);
}
@Test
public void adjuster_firstDayOfNextYear() {
MinguoDate updatedDate = minguoDate.with(TemporalAdjusters.firstDayOfNextYear());
System.out.println("firstDayOfNextYear : " + updatedDate);
}
@Test
public void adjuster_firstDayOfNextMonth() {
MinguoDate updatedDate = minguoDate.with(TemporalAdjusters.firstDayOfNextMonth());
System.out.println("firstDayOfNextMonth : " + updatedDate);
}
@Test
public void adjuster_lastDayOfMonth() {
MinguoDate updatedDate = minguoDate.with(TemporalAdjusters.lastDayOfMonth());
System.out.println("lastDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_nextMonday() {
MinguoDate updatedDate = minguoDate.with(TemporalAdjusters.next(DayOfWeek.MONDAY));
System.out.println("nextMonday : " + updatedDate);
}
@Test
public void adjuster_firstInMonth() {
MinguoDate updatedDate = minguoDate.with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY));
System.out.println("firstInMonth_Monday: " + updatedDate);
}
@Test
public void adjuster_previousWednesday() {
MinguoDate updatedDate = minguoDate.with(TemporalAdjusters.previous(DayOfWeek.WEDNESDAY));
System.out.println("previousWednesday : " + updatedDate);
}
@Test
public void tenDaysLater() {
TemporalAdjuster tenDaysFromNow = temporal -> temporal.plus(10, ChronoUnit.DAYS);
MinguoDate localTimeUpdate = minguoDate.with(tenDaysFromNow);
System.out.println("Ten Days later : " + localTimeUpdate);
}
}5.5 TemporalAdjusters_JapaneseDateTest
Java 8 JapaneseDate represents a date in the Japanese Imperial calendar system. I will repeat the same adjustment for the JapaneseDate class.
TemporalAdjusters_JapaneseDateTest.java
package com.zheng.demo;
import java.time.DayOfWeek;
import java.time.chrono.JapaneseDate;
import java.time.temporal.ChronoUnit;
import java.time.temporal.TemporalAdjuster;
import java.time.temporal.TemporalAdjusters;
import org.junit.Before;
import org.junit.Test;
public class TemporalAdjusters_JapaneseDateTest {
private JapaneseDate japaneseDate;
@Before
public void setup() {
japaneseDate = JapaneseDate.now();
System.out.println("\nCurrent JapaneseDate : " + japaneseDate);
}
@Test
public void adjuster_firstDayOfMonth() {
JapaneseDate updatedDate = japaneseDate.with(TemporalAdjusters.firstDayOfMonth());
System.out.println("firstDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_firstDayOfYear() {
JapaneseDate updatedDate = japaneseDate.with(TemporalAdjusters.firstDayOfYear());
System.out.println("firstDayOfYear : " + updatedDate);
}
@Test
public void adjuster_lastDayOfYear() {
JapaneseDate updatedDate = japaneseDate.with(TemporalAdjusters.lastDayOfYear());
System.out.println("lastDayOfYear : " + updatedDate);
}
@Test
public void adjuster_firstDayOfNextYear() {
JapaneseDate updatedDate = japaneseDate.with(TemporalAdjusters.firstDayOfNextYear());
System.out.println("firstDayOfNextYear : " + updatedDate);
}
@Test
public void adjuster_firstDayOfNextMonth() {
JapaneseDate updatedDate = japaneseDate.with(TemporalAdjusters.firstDayOfNextMonth());
System.out.println("firstDayOfNextMonth : " + updatedDate);
}
@Test
public void adjuster_lastDayOfMonth() {
JapaneseDate updatedDate = japaneseDate.with(TemporalAdjusters.lastDayOfMonth());
System.out.println("lastDayOfMonth : " + updatedDate);
}
@Test
public void adjuster_nextMonday() {
JapaneseDate updatedDate = japaneseDate.with(TemporalAdjusters.next(DayOfWeek.MONDAY));
System.out.println("nextMonday : " + updatedDate);
}
@Test
public void adjuster_firstInMonth() {
JapaneseDate updatedDate = japaneseDate.with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY));
System.out.println("firstInMonth_Monday: " + updatedDate);
}
@Test
public void adjuster_previousWednesday() {
JapaneseDate updatedDate = japaneseDate.with(TemporalAdjusters.previous(DayOfWeek.WEDNESDAY));
System.out.println("previousWednesday : " + updatedDate);
}
@Test
public void tenDaysLater() {
TemporalAdjuster tenDaysFromNow = temporal -> temporal.plus(10, ChronoUnit.DAYS);
JapaneseDate localTimeUpdate = japaneseDate.with(tenDaysFromNow);
System.out.println("Ten Days later : " + localTimeUpdate);
}
}6. Summary
In this example, we reviewed Java 8 Date time API and demonstrated how to use the pre-defined static methods in TemporalAdjusters to adjust the date at LocalDate, LocalDateTime, JapaneseDate, MinguoDate, and ZonedDateTime.
7. Download the Source Code
This example consists of a Maven project which adjusts LocalDate, LocatDateTime, JapaneseDate, MinguoDate, and ZonedDateTime using Java 8 TemporalAdjusters.
Download
You can download the full source code of this example here: Java 8 TemporalAdjusters Example
You can download the full source code of this example here: Java 8 TemporalAdjusters Example
