[patch] Fix for one hour off on DST change days in getExcelDate

getExcelDate-DST-fix.patch (text/plain), 8.30 KB, created by Hack Kampbjorn on 2004-03-10 16:46:39 UTC

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Description: Fix for one hour off on DST change days in getExcelDate

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Creator: Hack Kampbjorn

Created: 2004-03-10 16:46:39 UTC

Size: 8.30 KB

patch

obsolete

>Index: src/java/org/apache/poi/hssf/usermodel/HSSFDateUtil.java >=================================================================== >RCS file: /home/cvspublic/jakarta-poi/src/java/org/apache/poi/hssf/usermodel/HSSFDateUtil.java,v >retrieving revision 1.7 >diff -u -r1.7 HSSFDateUtil.java >--- src/java/org/apache/poi/hssf/usermodel/HSSFDateUtil.java 1 Jan 2004 09:03:32 -0000 1.7 >+++ src/java/org/apache/poi/hssf/usermodel/HSSFDateUtil.java 10 Mar 2004 16:43:44 -0000 >@@ -70,6 +70,7 @@ > * @author Michael Harhen > * @author Glen Stampoultzis (glens at apache.org) > * @author Dan Sherman (dsherman at isisph.com) >+ * @author Hack Kampbjorn (hak at 2mba.dk) > */ > > public class HSSFDateUtil >@@ -105,9 +106,19 @@ > } > else > { >+ // Because of daylight time saving we cannot use >+ // date.getTime() - calStart.getTimeInMillis() >+ // as the difference in milliseconds between 00:00 and 04:00 >+ // can be 3, 4 or 5 hours but Excel expects it to always >+ // 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 ) DAY_MILLISECONDS; > calStart = dayStart(calStart); >- double fraction = (date.getTime() - calStart.getTime().getTime()) >- / ( double ) DAY_MILLISECONDS; > > return fraction + ( double ) absoluteDay(calStart) > - CAL_1900_ABSOLUTE; >@@ -133,10 +144,20 @@ > * Given an Excel date with either 1900 or 1904 date windowing, > * converts it to a java.util.Date. > * >+ * NOTE: If the default <code>TimeZone</code> in Java uses Daylight >+ * Saving Time then the conversion back to an Excel date may not give >+ * the same value, that is the comparison >+ * <CODE>excelDate == getExcelDate(getJavaDate(excelDate,false))</CODE> >+ * is not always true. For example if default timezone is >+ * <code>Europe/Copenhagen</code>, on 2004-03-28 the minute after >+ * 01:59 CET is 03:00 CEST, if the excel date represents a time between >+ * 02:00 and 03:00 then it is converted to past 03:00 summer time >+ * > * @param date The Excel date. > * @param use1904windowing true if date uses 1904 windowing, > * or false if using 1900 date windowing. > * @return Java representation of the date, or null if date is not a valid Excel date >+ * @see java.util.TimeZone > */ > public static Date getJavaDate(double date, boolean use1904windowing) { > if (isValidExcelDate(date)) { >Index: src/testcases/org/apache/poi/hssf/usermodel/TestHSSFDateUtil.java >=================================================================== >RCS file: /home/cvspublic/jakarta-poi/src/testcases/org/apache/poi/hssf/usermodel/TestHSSFDateUtil.java,v >retrieving revision 1.3 >diff -u -r1.3 TestHSSFDateUtil.java >--- src/testcases/org/apache/poi/hssf/usermodel/TestHSSFDateUtil.java 30 Apr 2003 04:38:58 -0000 1.3 >+++ src/testcases/org/apache/poi/hssf/usermodel/TestHSSFDateUtil.java 10 Mar 2004 16:43:46 -0000 >@@ -58,7 +58,9 @@ > import junit.framework.TestCase; > > import java.util.Date; >+import java.util.Calendar; > import java.util.GregorianCalendar; >+import java.util.TimeZone; > > /** > * Class TestHSSFDateUtil >@@ -66,6 +68,7 @@ > * > * @author > * @author Dan Sherman (dsherman at isisph.com) >+ * @author Hack Kampbjorn (hak at 2mba.dk) > * @version %I%, %G% > */ > >@@ -115,4 +118,111 @@ > dateIf1904.getTime(), > HSSFDateUtil.getJavaDate(excelDate,true).getTime()); > } >+ >+ /** >+ * Checks the conversion of a java.util.date to Excel on a day when >+ * Daylight Saving Time starts. >+ */ >+ public void testExcelConversionOnDSTStart() { >+ TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen"); >+ TimeZone.setDefault(cet); >+ Calendar cal = new GregorianCalendar(2004, Calendar.MARCH, 28); >+ for (int hour = 0; hour < 24; hour++) { >+ >+ // Skip 02:00 CET as that is the Daylight change time >+ // and Java converts it automatically to 03:00 CEST >+ if (hour == 2) { >+ continue; >+ } >+ >+ cal.set(Calendar.HOUR_OF_DAY, hour); >+ Date javaDate = cal.getTime(); >+ double excelDate = HSSFDateUtil.getExcelDate(javaDate); >+ double difference = excelDate - Math.floor(excelDate); >+ int differenceInHours = (int) (difference * 24 * 60 + 0.5) / 60; >+ assertEquals("Checking " + hour + " hour on Daylight Saving Time start date", >+ hour, >+ differenceInHours); >+ assertEquals("Checking " + hour + " hour on Daylight Saving Time start date", >+ javaDate.getTime(), >+ HSSFDateUtil.getJavaDate(excelDate).getTime()); >+ } >+ } >+ >+ /** >+ * Checks the conversion of an Excel date to a java.util.date on a day when >+ * Daylight Saving Time starts. >+ */ >+ public void testJavaConversionOnDSTStart() { >+ TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen"); >+ TimeZone.setDefault(cet); >+ Calendar cal = new GregorianCalendar(2004, Calendar.MARCH, 28); >+ double excelDate = HSSFDateUtil.getExcelDate(cal.getTime()); >+ double oneHour = 1.0 / 24; >+ double oneMinute = oneHour / 60; >+ for (int hour = 0; hour < 24; hour++, excelDate += oneHour) { >+ >+ // Skip 02:00 CET as that is the Daylight change time >+ // and Java converts it automatically to 03:00 CEST >+ if (hour == 2) { >+ continue; >+ } >+ >+ cal.set(Calendar.HOUR_OF_DAY, hour); >+ Date javaDate = HSSFDateUtil.getJavaDate(excelDate); >+ assertEquals("Checking " + hour + " hours on Daylight Saving Time start date", >+ excelDate, >+ HSSFDateUtil.getExcelDate(javaDate), oneMinute); >+ } >+ } >+ >+ /** >+ * Checks the conversion of a java.util.Date to Excel on a day when >+ * Daylight Saving Time ends. >+ */ >+ public void testExcelConversionOnDSTEnd() { >+ TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen"); >+ TimeZone.setDefault(cet); >+ Calendar cal = new GregorianCalendar(2004, Calendar.OCTOBER, 31); >+ for (int hour = 0; hour < 24; hour++) { >+ cal.set(Calendar.HOUR_OF_DAY, hour); >+ Date javaDate = cal.getTime(); >+ double excelDate = HSSFDateUtil.getExcelDate(javaDate); >+ double difference = excelDate - Math.floor(excelDate); >+ int differenceInHours = (int) (difference * 24 * 60 + 0.5) / 60; >+ assertEquals("Checking " + hour + " hour on Daylight Saving Time end date", >+ hour, >+ differenceInHours); >+ assertEquals("Checking " + hour + " hour on Daylight Saving Time start date", >+ javaDate.getTime(), >+ HSSFDateUtil.getJavaDate(excelDate).getTime()); >+ } >+ } >+ >+ /** >+ * Checks the conversion of an Excel date to java.util.Date on a day when >+ * Daylight Saving Time ends. >+ */ >+ public void testJavaConversionOnDSTEnd() { >+ TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen"); >+ TimeZone.setDefault(cet); >+ Calendar cal = new GregorianCalendar(2004, Calendar.OCTOBER, 31); >+ double excelDate = HSSFDateUtil.getExcelDate(cal.getTime()); >+ double oneHour = 1.0 / 24; >+ double oneMinute = oneHour / 60; >+ for (int hour = 0; hour < 24; hour++, excelDate += oneHour) { >+ cal.set(Calendar.HOUR_OF_DAY, hour); >+ Date javaDate = HSSFDateUtil.getJavaDate(excelDate); >+ assertEquals("Checking " + hour + " hours on Daylight Saving Time start date", >+ excelDate, >+ HSSFDateUtil.getExcelDate(javaDate), oneMinute); >+ } >+ } >+ >+ public static void main(String [] args) { >+ System.out >+ .println("Testing org.apache.poi.hssf.usermodel.TestHSSFDateUtil"); >+ junit.textui.TestRunner.run(TestHSSFDateUtil.class); >+ } >+ > } View Attachment As Diff View Attachment As Raw

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