Java Period

Introduction to Java Period

A period in Java is a class, which is use to measure time in years, months and days. The package of the Period class in java is java.time.Period. The Period class object specifies the period of time or used to determine the difference between two times in years, months and days. A Period object is immutable and thread-safe also as the Period object is immutable, so we cannot change its values once it is created. But, we can create new Period objects based on another Period object. The Period class inherits an object class ( as the object is the superclass of all classes in java ) and implements the ChronoPeriod interface.

Syntax:

The syntax of the Period class declaration in java is:

public final class Period extends Object implements ChronoPeriod, Serializable
{
// variables and method of the class Period
}

Methods to Explain Java Period

The lists of Period class methods are explained below with example code; an example code can be used further for similar methods (as for each method example code not given):

• long get(TemporalUnit unit): Return the value of the requested unit.
• The static Period between(LocalDate startInclusive, LocalDate endExclusive): Return Period object is the period between two dates.of the number of years, months, and days.

Code:

import java.time.Period;
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
public class PeriodClassDemo {
public static void main(String[] args) {
Period p = Period.between(LocalDate.ofYearDay(2017, 20), LocalDate.ofYearDay(2017, 30) );
System.out.println(p);
System.out.println(p.get(ChronoUnit.DAYS));
System.out.println(p.get(ChronoUnit.MONTHS));
System.out.println(p.get(ChronoUnit.YEARS));
}
}

Output:

• Temporal addTo(Temporal temporal): Return Period object which is the addition of temporal and this Period object.

Code:

import java.time.Period;
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
import java.time.LocalDateTime;
public class PeriodClassDemo {
public static void main(String[] args) {
Period period = Period.of(1,1,1);
LocalDateTime d = LocalDateTime.now();
System.out.println(d);
d = (LocalDateTime)period.addTo(d);
System.out.println(d);
}
}

Output:

• boolean equals(Object otherPeriod): Checks this Period with specified Period and return Boolean.
• boolean isNegative(): Return True if this Period is negative.
• boolean isZero(): Return True if this Period is negative.

Code:

import java.time.Period;
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
import java.time.LocalDateTime;
public class PeriodClassDemo {
public static void main(String[] args) {
Period p1 = Period.of(1,1,1);
Period p2 = Period.of(10,5,2);
Period p3 = Period.of(10,5,2);
System.out.println(p1.equals(p2));
System.out.println(p2.equals(p3));
System.out.println(p2.isNegative());
System.out.println(p2.isZero());
}
}

Output:

• static Duratio from(TemporalAmount amount): Obtains an instance of Period from a temporal amount.

Code:

import java.time.Period;
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
import java.time.LocalDateTime;
public class PeriodClassDemo {
public static void main(String[] args) {
Period p = Period.from(Period.of(10, 5, 2) );
System.out.println(p);
}
}

Output:

• IsoChronology getChronology(): Return the chronology of this period, which is of the ISO calendar system.
• int getDays(): Return Period in days.
• int getMonths(): Return Period in months.
• List<TemporalUnit> getUnits(): Return set of units supported by this Period.
• int hashCode(): Return hash code for this Period.

Code:

import java.time.Period;
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
import java.time.LocalDateTime;
public class PeriodClassDemo {
public static void main(String[] args) {
Period p = Period.from(Period.of(10, 5, 2) );
System.out.println(p.getChronology());
System.out.println(p.get(ChronoUnit.MONTHS));
System.out.println(p.getDays());
System.out.println(p.getMonths());
System.out.println(p.getYears());
System.out.println(p.getClass());
System.out.println(p.getUnits());
}
}

Output:

• Period minus(TemporalAmount amountToSubtract): Returns object resulting from this Period subtracted with the specified Period.
• Period minusDays(long daysToSubtract): Returns object, which is subtracted with the specified Days.
• Period mindsmonths(long months): Returns object, which is the result of this period subtracted with the specified months.
• Period minusYears(long years): Returns object, which is the result of this period subtracted with the specified years.
• Period multipliedBy(long multiplicand): Returns a period object, which is multiplied by the scalar.
• Period negated(): Returns a period object that results from this period with the length negated.
• Period normalized(): Returns a period object that results from this period with normalized in the years and months.
• static Period of(int years, int months, int days): Returns a Period object representing a number of years, months and days.
• static Period ofDays(int days): Returns a Period object of a number of days.
• static Period ofMonths(int months): Returns a Period object of a number of months.
• static Period ofWeeks(int weeks): Returns a Period object of a number of weeks.
• static Period ofYears(int years): Returns a Period object of a number of weeks.

Code:

import java.time.Period;
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
import java.time.LocalDateTime;
public class PeriodClassDemo {
public static void main(String[] args) {
Period p1 = Period.of(10,5,2);
Period p2 = Period.of(20,5,2);
System.out.println(p1.getDays());
System.out.println(p2.getDays());
System.out.println(p1.minus(p2).getDays());
System.out.println(p1.minusDays(2).getDays());
System.out.println(p1.minusMonths(1).getDays());
System.out.println(p1.minusYears(1).getDays());
System.out.println(p1.multipliedBy(2).getDays());
System.out.println(p1.negated().getDays());
System.out.println(p1.normalized().getDays());
Period p3 = Period.ofDays(1);
System.out.println(p3.getDays( ));
Period p4 = Period.ofMonths(2);
System.out.println(p4.getMonths());
}
}

Output:

• static Period parse(CharSequence text): Return Period object from a text, example PnYnMnD.
• Period plus(TemporalAmount amountToAdd): Return period object of this Period with added the specified period.
• Period plusDays(long daysToAdd ): Return a period object of this period with added the specified days.
• Period plusMonths(long monthsToAdd): Return a period object of this period with added the specified months.
• Period plusYears(long yearsToAdd): Return a period object of this period with added the specified years.

Code:

import java.time.Period;
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
import java.time.LocalDateTime;
public class PeriodClassDemo {
public static void main(String[] args) {
Period p1 = Period.of(10,5,2);
Period p2 = Period.parse("P1Y2M3D");
System.out.println(p2.getMonths());
Period p3 = p1.plus(Period.ofDays(5));
System.out.println(p3);
}
}

Output:

• Temporal subtractFrom(Temporal temporal): Return Subtraction of this period from a temporal object.
• String toString(): Return this period in string representation, for example, as PT8H6M12.345S.
• long toTotalMonths(): Return the total number of months in this period.
• Period withDays(int days): Return a period object of this period with the specified amount of days.
• Period withMonths(int months): Return a period object of this period with the specified amount of months.
• Period withYears(int years): Return a period object of this period with the specified amount of Years.

Code:

import java.time.Period;
import java.time.LocalDate;
import java.time.temporal.ChronoUnit;
import java.time.LocalDateTime;
public class PeriodClassDemo {
public static void main(String[] args) {
Period p1 = Period.of(10,5,2);
System.out.println(p1);
LocalDateTime d = LocalDateTime.now();
System.out.println(d);
d = (LocalDateTime)p1.subtractFrom(d);
System.out.println(d);
System.out.println(p1.toString());
System.out.println(p1.toTotalMonths());
System.out.println(p1.withDays(2));
System.out.println(p1.toString());
System.out.println(p1.withMonths(1));
System.out.println(p1.toString());
}
}

Output:

Conclusion

The Period class is one of the built-in class in java, which is used to measure time in years, months, and days and add, subtract, convert the period, or in simple word, the period class allows to perform an operation on day or month or year period. The period class is available in java.time.Period package of java.

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