<!-- Don't forget to update status.xml too! -->
<release version="3.1-beta1" date="2008-??-??">
+ <action dev="POI-DEVELOPERS" type="fix">38641 - Handle timezones better with cell.setCellValue(Calendar), so now 20:00-03:00, 20:00+00:00 and 20:00+03:00 will all be recorded as 20:00, and not 17:00 / 20:00 / 23:00 (pass a Date not a Calendar for old behaviour)</action>
<action dev="POI-DEVELOPERS" type="fix">44373 - Have HSSFDateUtil.isADateFormat recognize more formats as being dates</action>
<action dev="POI-DEVELOPERS" type="add">37923 - Support for Excel hyperlinks</action>
<action dev="POI-DEVELOPERS" type="add">Implement hashCode() and equals(obj) on HSSFFont and HSSFCellStyle</action>
<!-- Don't forget to update changes.xml too! -->
<changes>
<release version="3.1-beta1" date="2008-??-??">
+ <action dev="POI-DEVELOPERS" type="fix">38641 - Handle timezones better with cell.setCellValue(Calendar), so now 20:00-03:00, 20:00+00:00 and 20:00+03:00 will all be recorded as 20:00, and not 17:00 / 20:00 / 23:00 (pass a Date not a Calendar for old behaviour)</action>
<action dev="POI-DEVELOPERS" type="fix">44373 - Have HSSFDateUtil.isADateFormat recognize more formats as being dates</action>
<action dev="POI-DEVELOPERS" type="add">37923 - Support for Excel hyperlinks</action>
<action dev="POI-DEVELOPERS" type="add">Implement hashCode() and equals(obj) on HSSFFont and HSSFCellStyle</action>
/**
* set a date value for the cell. Excel treats dates as numeric so you will need to format the cell as
* a date.
+ *
+ * This will set the cell value based on the Calendar's timezone. As Excel
+ * does not support timezones this means that both 20:00+03:00 and
+ * 20:00-03:00 will be reported as the same value (20:00) even that there
+ * are 6 hours difference between the two times. This difference can be
+ * preserved by using <code>setCellValue(value.getTime())</code> which will
+ * automatically shift the times to the default timezone.
*
* @param value the date value to set this cell to. For formulas we'll set the
* precalculated value, for numerics we'll set its value. For othertypes we
*/
public void setCellValue(Calendar value)
{
- setCellValue(value.getTime());
+ setCellValue( HSSFDateUtil.getExcelDate(value, this.book.isUsing1904DateWindowing()) );
}
/**
public static double getExcelDate(Date date, boolean use1904windowing) {
Calendar calStart = new GregorianCalendar();
calStart.setTime(date); // If date includes hours, minutes, and seconds, set them to 0
-
- if ((!use1904windowing && calStart.get(Calendar.YEAR) < 1900) ||
- (use1904windowing && calStart.get(Calendar.YEAR) < 1904))
+ return internalGetExcelDate(calStart, use1904windowing);
+ }
+ /**
+ * Given a Date in the form of a Calendar, converts it into a double
+ * representing its internal Excel representation, which is the
+ * number of days since 1/1/1900. Fractional days represent hours,
+ * minutes, and seconds.
+ *
+ * @return Excel representation of Date (-1 if error - test for error by checking for less than 0.1)
+ * @param date the Calendar holding the date to convert
+ * @param use1904windowing Should 1900 or 1904 date windowing be used?
+ */
+ public static double getExcelDate(Calendar date, boolean use1904windowing) {
+ // Don't alter the supplied Calendar as we do our work
+ return internalGetExcelDate( (Calendar)date.clone(), use1904windowing );
+ }
+ private static double internalGetExcelDate(Calendar date, boolean use1904windowing) {
+ if ((!use1904windowing && date.get(Calendar.YEAR) < 1900) ||
+ (use1904windowing && date.get(Calendar.YEAR) < 1904))
{
return BAD_DATE;
} else {
// be 4 hours.
// E.g. 2004-03-28 04:00 CEST - 2004-03-28 00:00 CET is 3 hours
// and 2004-10-31 04:00 CET - 2004-10-31 00:00 CEST is 5 hours
- double fraction = (((calStart.get(Calendar.HOUR_OF_DAY) * 60
- + calStart.get(Calendar.MINUTE)
- ) * 60 + calStart.get(Calendar.SECOND)
- ) * 1000 + calStart.get(Calendar.MILLISECOND)
+ double fraction = (((date.get(Calendar.HOUR_OF_DAY) * 60
+ + date.get(Calendar.MINUTE)
+ ) * 60 + date.get(Calendar.SECOND)
+ ) * 1000 + date.get(Calendar.MILLISECOND)
) / ( double ) DAY_MILLISECONDS;
- calStart = dayStart(calStart);
+ Calendar calStart = dayStart(date);
double value = fraction + absoluteDay(calStart, use1904windowing);
}
}
+ /**
+ * Tests that we deal with timezones properly
+ */
+ public void testCalendarConversion() {
+ GregorianCalendar date = new GregorianCalendar(2002, 0, 1, 12, 1, 1);
+ Date expected = date.getTime();
+ double expectedExcel = HSSFDateUtil.getExcelDate(expected);
+
+ // Iteratating over the hours exposes any rounding issues.
+ for (int hour = -12; hour <= 12; hour++)
+ {
+ String id = "GMT" + (hour < 0 ? "" : "+") + hour + ":00";
+ date.setTimeZone(TimeZone.getTimeZone(id));
+ date.set(Calendar.HOUR_OF_DAY, 12);
+ double excelDate = HSSFDateUtil.getExcelDate(date, false);
+ Date javaDate = HSSFDateUtil.getJavaDate(excelDate);
+
+ // Should match despite timezone
+ assertEquals("Checking timezone " + id, expected.getTime(), javaDate.getTime());
+ }
+ }
+
+
/**
* Tests that we correctly detect date formats as such
*/
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