XYZ CODE: Define and create and manage date-based and time-based events using Instant, Period, Duration, and TemporalUnit

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The Instant class represents a specific moment in GMT time zone.

Instant, Period, Duration, TemporalUnit

There are a few ways of getting an Instance:

now(): Instant instant = Instant.now();
ofEpochSecond(): Instant instant = Instant.ofEpochSecond(1518619048);
with ZonedDateTime: Instant instant = ZonedDateTime.of(2015, 1, 1, 1, 1, 1, "US/Eastern").toInstant();
from another Instant: Instant instant = Instant.now().plus(1, ChronoUnit.HOURS);

The Period and Duration classes represents a span of time. Period is for a day or more of time, Duration is for smaller units of time.

There are five ways to create a Period:

There are many ways to create a Duration:

Duration d = Duration.ofDays(1);
Duration d = Duration.ofHours(1);
Duration d = Duration.ofMinutes(1);
Duration d = Duration.ofSeconds(1);
Duration d = Duration.ofMillis(1);
Duration d = Duration.ofNanos(1);
Duration d = Duration.of(1, ChronoUnit.DAYS);
Duration d = Duration.of(1, ChronoUnit.HOURS);
Duration d = Duration.of(1, ChronoUnit.MINUTES);
Duration d = Duration.of(1, ChronoUnit.SECONDS);
Duration d = Duration.of(1, ChronoUnit.MILLIS);
Duration d = Duration.of(1, ChronoUnit.NANOS);
Duration d = Duration.of(1, ChronoUnit.HALF_DAYS);
Duration d = ChronoUnit.HOURS.between(LocalTime.of(1, 10), LocalTime.of(2, 1));
Duration d = ChronoUnit.MINUTES.between(LocalTime.of(1, 10), LocalTime.of(2, 1));

Notice if you call the Period and Duration's of() method in a chain, only the last call count. For example,

Duration.ofDays(1).ofHours(1).ofMinutes(1) created a 1 minute duration.

Also notice toString of Period start with P, toString of Duration start with PT.

OCPJP>cat DatesInstantsTest.java 

import java.time.*;

import java.time.temporal.ChronoUnit;

public class DatesInstantsTest {

    public static void main(String... args) {

        Instant start = Instant.now();

        long epo = start.getEpochSecond();

        ZonedDateTime st = ZonedDateTime.ofInstant(start, ZoneId.of("US/Eastern"));

        ZonedDateTime zdt = ZonedDateTime.of(st.getYear(), st.getMonthValue(), st.getDayOfMonth()

                , st.getHour(), st.getMinute(), st.getSecond(), st.getNano(), st.getZone());

        Instant end = zdt.plus(1, ChronoUnit.SECONDS).toInstant();

        System.out.println(isExpired(start, end, Duration.ofHours(1)));

        System.out.println("====================");

        start = Instant.ofEpochSecond(epo);

        boolean r = isExpired(LocalDateTime.ofInstant(start, ZoneId.of("US/Eastern"))

                , LocalDateTime.now(), Period.of(0, 0, 0));

        System.out.println(r);

}

    public static boolean isExpired(Instant start, Instant end, Duration ttl) {

        System.out.println(start);

        System.out.println(end);

        Duration d = Duration.between(start, end);

        System.out.println(d);

        d = d.minusNanos(ttl.toNanos());

        System.out.println(d);

        return end.isAfter(start.plus(ttl));

}

    public static boolean isExpired(LocalDateTime start, LocalDateTime end, Period ttl) {

        System.out.println(start);

        System.out.println(end);

        Duration d = Duration.between(end, start);

        System.out.println(d);

        Period p = Period.between(end.toLocalDate(), start.toLocalDate());

        System.out.println(p);

        return start.isBefore(end.minus(ttl));

}

}

OCPJP>

OCPJP>

OCPJP>javac DatesInstantsTest.java 

OCPJP>java DatesInstantsTest

2018-02-14T17:18:44.222Z

2018-02-14T17:18:45.222Z

PT1S

PT-59M-59S

false

====================

2018-02-14T12:18:44

2018-02-14T12:18:44.298

PT-0.298S

P0D

true

OCPJP>

The above example is intentionally verbose to use more Duration, Period, Instant and ChronoUnit APIs and Constants.