CODEWITHSUNDEEP
javatimetimezonejodatime
Julien
Julien

Reputation: 1925

JodaTime: how to find a future time in a different timezone

I need to find the point in time, when it will next be 7:00 in the morning in Auckland (in New Zealand)

I am using joda-time 2.6

    <dependency>
        <groupId>joda-time</groupId>
        <artifactId>joda-time</artifactId>
        <version>2.6</version>
    </dependency>

When testing with the following

import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;

public class FindDateTimeInFuture {
    static DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss.SSS z Z");

    public static void main(String[] args) {
        // Use UTC as application wide default
        DateTimeZone.setDefault(DateTimeZone.UTC);

        System.out.println("now UTC         = " + formatter.print(DateTime.now()));

        System.out.println("now in Auckland = " + formatter.print(DateTime.now(DateTimeZone.forID("Pacific/Auckland"))));

        System.out.println("7 AM Auckland   = " + formatter.print(DateTime.now(DateTimeZone.forID("Pacific/Auckland")).withTime(7, 0, 0, 0)));
    }
}

If I run the above after Midnight in Auckland, it is fine, it is 

now UTC         = 2016-09-01 13:37:26.844 UTC +0000
now in Auckland = 2016-09-02 01:37:26.910 NZST +1200
7 AM Auckland   = 2016-09-02 07:00:00.000 NZST +1200
                           ^ ok, in the future

But, if I run the above before Midnight in Auckland, I get the 7 AM in the past ...

now UTC         = 2016-09-01 09:37:48.737 UTC +0000
now in Auckland = 2016-09-01 21:37:48.831 NZST +1200
7 AM Auckland   = 2016-09-01 07:00:00.000 NZST +1200
                           ^ ko, in the past

Is there a way to tell joda-time to go forward when changing the time ?

Upvotes: 5

Views: 546

Answers (3)

vsminkov
vsminkov

Reputation: 11250

I think the most obvious solution may be correct one

DateTime nowAuckland = 
    DateTime.now(DateTimeZone.forID("Pacific/Auckland"));
boolean addDay = nowAuckland.getHourOfDay() >= 7;
DateTime aucklandAt700 = nowAuckland.withTime(7, 0, 0, 0);
if (addDay) {
    aucklandAt700 = aucklandAt700.plusDays(1);
}

You can just check if there is already more than 7:00 at Auckland and if so just increment number of days.

Upvotes: 3

Ramachandran.A.G
Ramachandran.A.G

Reputation: 4948

DateTime nowAuckland = DateTime.now(DateTimeZone.forID("Pacific/Auckland"));
DateTime currentTimeNow = DateTime.now(DateTimeZone.getDefault());
DateTime aucklandAt700 = nowAuckland.withTime(7, 0, 0, 0);
System.out.println(currentTimeNow);
Duration duration = new Interval(nowAuckland, aucklandAt700).toDuration();
System.out.println(currentTimeNow.plusMillis((int) duration.getMillis()));

Prints :

2016-09-01T21:07:13.444+05:30
2016-09-02T00:30:00.047+05:30

7 AM in NZ will be 00:30 in IST , which seems right as per google

*7:00 AM Friday, in Auckland, New Zealand is
12:30 AM Friday, Indian Standard Time (IST)*

Upvotes: 0

hunter
hunter

Reputation: 4173

private DateTime getNextDateTime(DateTime now, int hour)
{
    DateTime nextDateTime = now.withTime(hour, 0, 0, 0);
    if(nextDateTime.isBefore(now))
    {
        nextDateTime = nextDateTime.plusDays(1);
    }
    return nextDateTime;
}

Upvotes: 1

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