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From "Jarek (JIRA)" <j...@apache.org>
Subject [jira] [Created] (LANG-1219) FastDateFormat doesn't respect summer daylight in localized strings
Date Thu, 21 Apr 2016 14:10:25 GMT
Jarek created LANG-1219:
---------------------------

             Summary: FastDateFormat doesn't respect summer daylight in localized strings
                 Key: LANG-1219
                 URL: https://issues.apache.org/jira/browse/LANG-1219
             Project: Commons Lang
          Issue Type: Bug
          Components: lang.time.*
    Affects Versions: 3.4
            Reporter: Jarek


FastDateFormat can't properly parse dates with daylight saving in the "z" pattern. It always
returns date without daylight saving. Test case:

{code}
		SimpleDateFormat format = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss z", Locale.GERMANY);
		Date d1 = format.parse("26.10.2014 02:00:00 MESZ");
		Date d2 = format.parse("26.10.2014 02:00:00 MEZ");
		System.out.println(d1);
		System.out.println(d2);
		FastDateFormat formatt = FastDateFormat.getInstance("dd.MM.yyyy HH:mm:ss z", Locale.GERMANY);
		Date d3 = formatt.parse("26.10.2014 02:00:00 MESZ");
		Date d4 = formatt.parse("26.10.2014 02:00:00 MEZ");
		System.out.println(d3);
		System.out.println(d4);	
{/code}

returns:
SDF: Sun Oct 26 02:00:00 CEST 2014
SDF: Sun Oct 26 02:00:00 CET 2014
FDF: Sun Oct 26 02:00:00 CET 2014
FDF:  Sun Oct 26 02:00:00 CET 2014

FastDateFormat returns the same date, which is wrong.

Bug is in the FastDateParser.TimeZoneStrategy.setCalendar:
{code}
@Override
        void setCalendar(final FastDateParser parser, final Calendar cal, final String value)
{
            TimeZone tz;
            if(value.charAt(0)=='+' || value.charAt(0)=='-') {
                tz= TimeZone.getTimeZone("GMT"+value);
            }
            else if(value.startsWith("GMT")) {
                tz= TimeZone.getTimeZone(value);
            }
            else {
                tz= tzNames.get(value);
                if(tz==null) {
                    throw new IllegalArgumentException(value + " is not a supported timezone
name");
                }
            }
            cal.setTimeZone(tz);
        }
{/code}

It's not enough to just call: cal.setTimeZone.
If zone names in standard and daylight time are different, you have to check the name in DateFormatSymbols.getInstance(locale).getZoneStrings();
and if it's >= 3, you have to activate daylight mode.Just like SimpleDateFormat does it:
{code}
1491            // (abbreviation) for both standard and daylight time,
1492            // let the time zone in the Calendar decide which one.
1493            if (!useSameName) {
1494                calendar.set(Calendar.ZONE_OFFSET, tz.getRawOffset());
1495                calendar.set(Calendar.DST_OFFSET,
1496                             j >= 3 ? tz.getDSTSavings() : 0);
1497            }
{/code}




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