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I'm working with a Grails application and I can't find a clear way to translate a date from one TimeZone to the next/previous TimeZone available (I will define what I consider the next/previous Timezone below).

The facts: I'm working with date filters in a Grails Application so we can retrieve information based on those filters. The application supports TimeZone so the logged user can set his profile to a particular Timezone. The dates of the filter are on UTC format and the information on the database is stored also on UTC.

The question: The user logged has his profile on Timezone UTC+00. There is a predefined date filter called "This Week", when a user clicks on it generate a period of dates corresponding to the current week in UTC so we can bring all the information on the database from the current week.

If we are on the current day (Thu 19 Nov 2015) the dates the filter will generate for "This Week" to look on the database would be:

Sun Nov 15 00:00:00 UTC 2015 to Sun Nov 22 23:59:59 UTC 2015

This is correct and will bring all the information on the database on that period.

Now, suppose the user doing this has set a Timezone UTC +01.

If we are on the current day (Thu 19 Nov 2015) the dates the filter will generate to look on the database would be the same period:

Sun Nov 15 00:00:00 UTC 2015 to Sun Nov 22 23:59:59 UTC 2015

But in this case I need to translate them to a correct TimeZone because the "This Week" for the current user won't be the same for a user on UTC +01 this is because for this user the date Sun Nov 15 00:00:00 would correspond to the date Sun Nov 14 23:00:00 on the UTC time (since he/she is one hour ahead) and therefore when filter by "This Week" I should search on the database by the dates:

Sun Nov 14 23:00:00 UTC 2015 to Sun Nov 22 22:59:59 UTC 2015

The thing is I have created a method utcDateToUserTZ(date) to translate from an UTCDate to LocalTimeZone date but this would convert the UTC dates:

Sun Nov 15 00:00:00 UTC 2015 to Sun Nov 22 23:59:59 UTC 2015

into

Sun Nov 15 01:00:00 UTC 2015 to Sun Nov 23 00:59:59 UTC 2015

And that is not what I'm looking for. I need those dates to be translated to the previous TimeZone.

I hope no to be walking around with an issue that has a simpler solution, in which case I hope you can tell me if there exist something easier to solve this.

Thanks,

The method commented before is:

public DateTime utcDateToUserTZ(Date date) {

    TimeZone profileTimeZone = getCurrentUserProfile().timeZone
    DateTimeZone dateTimeZone = DateTimeZone.forTimeZone(profileTimeZone)

    return new DateTime(date, dateTimeZone).withZone(dateTimeZone)
}
Martín C
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  • _I have created a method to translate from an UTCDate to LocalTimeZone date_ Can you add that method here? I believe somewhere in this method the offset being `-01` is used as `+01`. Make sure the offset's value is used instead of its absolute value. Which means -1 offset should be used as -1 instead of it's absolute value `Math.abs(-1)`. – dmahapatro Nov 19 '15 at 16:11
  • Hi dmhapatro, I have edited the question and added the method, but I think the method is working fine, (do not take care of the offset since the timezone takes care of that), but is not what I'm looking for. – Martín C Nov 19 '15 at 17:24

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