DateFormat getPattern

[Steve Wood]

Hi guys,

I'm looking for a way to get the date pattern from the DateFormat class. They have a number of localized styles, but I can't seem to work out how to get the actual pattern string. This seems to be supported in the SimpleDateFormat class, but not DateFormat.

So, for example, what is the DateFormat.MEDIUM pattern for Japan? I'd like to do this so my application can display the pattern it is going to apply to the user.

Any help is much appreciated.

Cheers,

Steve

[Tim LeMaster]

If you look at the source for DateFormat calling DataFormat.getInstance()/getDateInstance()/getDateTimeInstance() calls SimpleDateFormat internally. So you can check to make sure its an instance of SimpleDateFormat and cast it and make the call to get the pattern.

Also all the pattern format strings are stored in the LocaleData

    
public class Main
{
public static void main(String[] args) throws Exception
{
DateFormat format = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.JAPAN);
if (format instanceof SimpleDateFormat)
{
SimpleDateFormat sdf = (SimpleDateFormat)format;
System.out.println("Pattern from class: " + sdf.toLocalizedPattern());
}

ResourceBundle r = LocaleData.getLocaleElements(Locale.JAPAN);
        String[] dateTimePatterns = r.getStringArray("DateTimePatterns");
                
        System.out.println("Pattern from bundle: " + dateTimePatterns[DateFormat.MEDIUM+4]);
}
}

[Steve Wood]

Thank you very much - that's superb.

Cheers,

Steve

[Jesper de Jong]

Just a warning:

Note that Tim's solution is not guaranteed to work on future versions of Java. The API documentation (which is the spec) does not say that DateFormat.getInstance() returns a SimpleDateFormat. In fact, in a future version of Java the implementation might be changed and your program won't work anymore if it does change.
[ December 08, 2006: Message edited by: Jesper Young ]