MessageFormat and Timezone

[Fred Gurkov]

Does anybody know how to set the time zone for a MessageFormat or even
better for a specific date field in it?

regards,
Fred.

[Grzegorz Pszona]

You should use DateFormat class.

or
You can prepare string before sets it in MessageFormat.
You can use Calendar class

for example:

( ... )
TimeZone tz = TimeZone.getTimeZone("GMT"); // for Greenwich
Time Zone
Calendar mCal = Calendar.getInstance( tz );

Date mDate = new Date(100, 06, 14, 10, 30, 0);
mCal.setTime(mDate); // deprecated!
// or
mCal.set( 100, 06, 14, 10, 30, 0);

String sDate = mCal.get(Calendar.HOUR) + ":" +
mCal.get(Calendar.MINUTE) + ":" +
mCal.get(Calendar.SECOND);

MessageFormat form = new MessageFormat( sDate );
( ... )

regards,
GP

"Fred Gurkov" <fr...@sunbay.com> wrote in message
news:39473271...@sunbay.com...

[Fred Gurkov]

Thanks. That's clear but my intention was to use uniform format and store it
in a properties file.

[Paul Hill]

Grzegorz Pszona wrote:
>
> You should use DateFormat class.
>
> or
> You can prepare string before sets it in MessageFormat.
> You can use Calendar class
>
> for example:
>
> ( ... )
> TimeZone tz = TimeZone.getTimeZone("GMT"); // for Greenwich
> Time Zone
> Calendar mCal = Calendar.getInstance( tz );

If you want this calendar to run on GMT time you must (instead of your local default).
mCal.setTimezone( tz );

>
> Date mDate = new Date(100, 06, 14, 10, 30, 0);
> mCal.setTime(mDate); // deprecated!

Calendar.setTime is not deprecated, just new Date(...) with many arguments.

> // or
> mCal.set( 100, 06, 14, 10, 30, 0);
>
> String sDate = mCal.get(Calendar.HOUR) + ":" +
> mCal.get(Calendar.MINUTE) + ":" +
> mCal.get(Calendar.SECOND);
>
> MessageFormat form = new MessageFormat( sDate );
> ( ... )

A SimpleDateFormat might come in handy here, but the original poster was
looking to use a MessageFormat.

To set the format for a date field I believe you need to do the following.
1. Construct a SimpleDateFormat with the TZ set correctly, you might use information
from the default format (DateFormat.getDateInstance())and set the TZ on that.
2. Use the MessageFormat.setFormat( index, format ) method to attach your specially
created format into a particular _field_ in the particular Message.

I don't see a way make all dates in a message change to a given TZ.

Hope that helps,
-Paul

If I had time I'd code this

>
> regards,
> GP
>
> "Fred Gurkov" <fr...@sunbay.com> wrote in message
> news:39473271...@sunbay.com...
> > Does anybody know how to set the time zone for a MessageFormat or even
> > better for a specific date field in it?
> >
> > regards,
> > Fred.
> >

--
Myriad Genetics: http://www.myriad.com/
Java FAQ: http://www.afu.com/javafaq.html (Section 9, Computer Dating)

[Fred Gurkov]

Thanks a lot Paul, you have inspired me to write quite acceptable code. I haven't paid
attention to the getFormats method of a MessageFormat. Here's an example:

import java.text.*;
import java.util.*;

public class Format {
public static void main(String argv[]) {
MessageFormat mf = new MessageFormat("The time is: {0, time, HH:mm}");

TimeZone tz = TimeZone.getTimeZone("GMT");

Object [] formats = mf.getFormats();
for (int i = 0; i < formats.length; i++) {
if (formats[i] instanceof SimpleDateFormat) {
((SimpleDateFormat)formats[i]).setTimeZone(tz);
}
}
Date date = new Date();
Object [] args = {date};
System.out.println(mf.format(args));
}
}

Best regards,
Fred.

[Paul Hill]

Fred Gurkov wrote:
>
> Thanks a lot Paul, you have inspired me to write quite acceptable code. I haven't paid
> attention to the getFormats method of a MessageFormat. Here's an example:

> for (int i = 0; i < formats.length; i++) {
> if (formats[i] instanceof SimpleDateFormat) {
> ((SimpleDateFormat)formats[i]).setTimeZone(tz);
> }
> }

Bravo! Obviously you can just go looking for the right objects in the
list of formats and tweak them. What someone might do is make a
TimeZoneMessageFormat() that contains a setTimeZone( TimeZone tz )

which I just did. I've run it and it seems to work.

import java.util.*;
import java.text.*;

public class TZMessageFormat extends MessageFormat {
public TZMessageFormat( String newPattern ) {
super( newPattern );
}

private TimeZone _tz; // for all dates/times in this message
public void setTimeZone( TimeZone tz ) {
_tz = tz;
applyTimeZone();
}

private void applyTimeZone() {
if ( _tz == null ) return;
// force the specific timezone on any date/times in the message
Object [] formats = getFormats();

for (int i = 0; i < formats.length; i++) {
if (formats[i] instanceof SimpleDateFormat) {

((SimpleDateFormat)formats[i]).setTimeZone(_tz);
}
}
}

public void applyPattern( String newPattern ) {
super.applyPattern( newPattern );
applyTimeZone();
}

public static void main(String[] args) {
TZMessageFormat mf = new TZMessageFormat( "The time is: {0, time, HH:mm}");
mf.setTimeZone( TimeZone.getTimeZone("GMT") );

Date date = new Date();

Object [] args1 = {date};
System.out.println(mf.format(args1));
// or as one line as
System.out.println( mf.format( new Object[] { new Date() } ) );