I think I have the solution.
When I ask the user for the timezone, I store it as an offset in minutes
from GMT. The problem occurs if the user reconnects after the timezone has
changed to/from daylight savings time relative to the date when he or she
originally chose the timezone. For example, if someone in continental
europe specifies their timezone in winter, it's GMT/UTC +60. In summer,
it's UTC+120... However, as I didn't know if they chose during or
before/after daylight savings changes, I would not be able to calculate
time-critical events correctly relative to the timezones of other users....
What I will do therefore is to store every timezone offset relative to
GMT/UTC. In order to do this, I'll use a reference timezone. For example,
I know that in winter, in the UK locale, GMT offset is 0, but during summer,
the offset is +60. I know therefore whether or not to apply changes.
Doesn't provide the perfect solution as I don't know which countries do or
do not apply such changes, but for the moment, given the countries I use, I
can get away with this (and a checkbox to say "do not apply daylight savings
changes").
-Chris
----- Original Message -----
From: "sandarbh" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, April 20, 2001 5:45 PM
Subject: Re: date problems
> Hi Chris ,
>
> please see following line of code
> *****************************************
> Calendar df_curr = Calendar.getInstance();
> Calendar df = Calendar.getInstance();
> ----------
> ---------
> Date dcurr =new Date(CurRec);
>
> df_curr.setTime(dcurr);
>
> ***********************
> so now i have two instances df and df_curr
>
> one set to systime and next to some other time.
> now i am extracting various values as
> int month_curr = df_curr.get(Calendar.MONTH);
>
> but i need to know exact difference irrespective of year between two dates
> in days..
>
> Can you please explain further..
>
> sandarbh
>
>
> ----- Original Message -----
> From: "chris brown" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Friday, April 20, 2001 3:45 PM
> Subject: Re: date problems
>
>
> > You should be able to extract a Date object (using Calendar.getTime()) ,
> > then from this Date, call getTime() to get a long (in milliseconds). Do
> the
> > same for your other date, then compare the two long values.
> >
> > A day can generally be assumed to be equal to :
> > 1000ms * 60s * 60m * 24h
> >
> > You may wish to set your two Calendar objects to 00:00:00.000
> (hh:mm:ss.ms)
> > before extracting the time to eliminate perhaps redundant information,
or
> > you could use modulus or or division operators (% or /) on the resulting
> > long values for the same thing. Depends upon what you need to do...
> >
> > In any case, this should work around any month or year boundary
problems.
> >
> > -Chris
> >
> > ----- Original Message -----
> > From: "sandarbh" <[EMAIL PROTECTED]>
> > To: <[EMAIL PROTECTED]>
> > Sent: Friday, April 20, 2001 1:37 PM
> > Subject: date problems
> >
> >
> > > Hi all,
> > > I want to have exact difference in days for two days in Java. If for
the
> > > current year , then I am able to extract exact info using calender
> class,
> > > but across the years its not possible?? can any one suggest a better
way
> > > please??
> > >
> > > Thanks in anticipation.
> > >
> > > sandarbh
> > >
> > >
> >
>
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