Support 1904 date windowing, in addition to 1900 date windowing (patch from bug #43551)

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@601004 13f79535-47bb-0310-9956-ffa450edef68

src/documentation/content/xdocs/changes.xml

@@ -36,6 +36,7 @@
 
 		<!-- Don't forget to update status.xml too! -->
         <release version="3.0.2-FINAL" date="2007-??-??">
+            <action dev="POI-DEVELOPERS" type="add">43551 - [PATCH] Support for 1904 date windowing in HSSF (previously only supported 1900 date windowing)</action>
             <action dev="POI-DEVELOPERS" type="add">41064 - [PATCH] Support for String continue records</action>
             <action dev="POI-DEVELOPERS" type="add">27511 - [PATCH] Support for data validation, via DVRecord and DVALRecord</action>
             <action dev="POI-DEVELOPERS" type="fix">43877 and 39512 - Fix for handling mixed OBJ and CONTINUE records.</action>

src/documentation/content/xdocs/status.xml

@@ -33,6 +33,7 @@
 	<!-- Don't forget to update changes.xml too! -->
     <changes>
         <release version="3.0.2-FINAL" date="2007-??-??">
+            <action dev="POI-DEVELOPERS" type="add">43551 - [PATCH] Support for 1904 date windowing in HSSF (previously only supported 1900 date windowing)</action>
             <action dev="POI-DEVELOPERS" type="add">41064 - [PATCH] Support for String continue records</action>
             <action dev="POI-DEVELOPERS" type="add">27511 - [PATCH] Support for data validation, via DVRecord and DVALRecord</action>
             <action dev="POI-DEVELOPERS" type="fix">43877 - Fix for handling mixed OBJ and CONTINUE records</action>

src/java/org/apache/poi/hssf/usermodel/HSSFCell.java

@@ -521,7 +521,7 @@ public class HSSFCell
      */
     public void setCellValue(Date value)
     {
-        setCellValue(HSSFDateUtil.getExcelDate(value));
+        setCellValue(HSSFDateUtil.getExcelDate(value, this.book.isUsing1904DateWindowing()));
     }
 
     /**

src/java/org/apache/poi/hssf/usermodel/HSSFDateUtil.java

@@ -35,6 +35,8 @@ import java.util.GregorianCalendar;
  * @author  Glen Stampoultzis (glens at apache.org)
  * @author  Dan Sherman (dsherman at isisph.com)
  * @author  Hack Kampbjorn (hak at 2mba.dk)
+ * @author  Alex Jacoby (ajacoby at gmail.com)
+ * @author  Pavel Krupets (pkrupets at palmtreebusiness dot com)
  */
 
 public class HSSFDateUtil
@@ -54,19 +56,26 @@ public class HSSFDateUtil
      * @return Excel representation of Date (-1 if error - test for error by checking for less than 0.1)
      * @param  date the Date
      */
-
+    public static double getExcelDate(Date date) {
-    public static double getExcelDate(Date date)
+    	return getExcelDate(date, false);
-    {
+    }
+    /**
+     * Given a Date, 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 Date
+     * @param use1904windowing Should 1900 or 1904 date windowing be used?
+     */
+    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
         
-        calStart.setTime(
+        if ((!use1904windowing && calStart.get(Calendar.YEAR) < 1900) || 
-            date);   // If date includes hours, minutes, and seconds, set them to 0
+            (use1904windowing && calStart.get(Calendar.YEAR) < 1904)) 
-        if (calStart.get(Calendar.YEAR) < 1900)
         {
             return BAD_DATE;
-        }
+        } else {
-        else
-        {
 	    // Because of daylight time saving we cannot use
 	    //     date.getTime() - calStart.getTimeInMillis()
 	    // as the difference in milliseconds between 00:00 and 04:00
@@ -81,10 +90,12 @@ public class HSSFDateUtil
                               ) / ( double ) DAY_MILLISECONDS;
             calStart = dayStart(calStart);
             
-            double value = fraction + absoluteDay(calStart);
+            double value = fraction + absoluteDay(calStart, use1904windowing);
             
-            if (value >= 60) {
+            if (!use1904windowing && value >= 60) {
-                value += 1;
+                value++;
+            } else if (use1904windowing) {
+                value--;
             }
             
             return value;
@@ -92,20 +103,25 @@ public class HSSFDateUtil
     }
     
     /**
-     * Given a excel date, converts it into a Date.
+     *  Given an Excel date with using 1900 date windowing, and
-     * Assumes 1900 date windowing.
+     *   converts it to a java.util.Date.
      *
-     * @param  date the Excel 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
      *  
-     * @return Java representation of a date (null if error)
+     *  @param date  The Excel date.
-     * @see #getJavaDate(double,boolean)
+     *  @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) {
-    public static Date getJavaDate(double date)
+    	return getJavaDate(date, false);
-    {
-        return getJavaDate(date,false);
     }
-    
     /**
      *  Given an Excel date with either 1900 or 1904 date windowing,
      *  converts it to a java.util.Date.
@@ -142,7 +158,7 @@ public class HSSFDateUtil
             GregorianCalendar calendar = new GregorianCalendar(startYear,0,
                                                      wholeDays + dayAdjust);
             int millisecondsInDay = (int)((date - Math.floor(date)) * 
-                                          (double) DAY_MILLISECONDS + 0.5);
+                                          DAY_MILLISECONDS + 0.5);
             calendar.set(GregorianCalendar.MILLISECOND, millisecondsInDay);
             return calendar.getTime();
         }
@@ -238,7 +254,7 @@ public class HSSFDateUtil
      *  Check if a cell contains a date
      *  Since dates are stored internally in Excel as double values 
      *  we infer it is a date if it is formatted as such. 
-     *  @see #isADateFormat(int,string)
+     *  @see #isADateFormat(int, String)
      *  @see #isInternalDateFormat(int)
      */
     public static boolean isCellDateFormatted(HSSFCell cell) {
@@ -259,7 +275,7 @@ public class HSSFDateUtil
      *   excel date formats.
      *  As Excel stores a great many of its dates in "non-internal"
      *   date formats, you will not normally want to use this method.
-     *  @see #isADateFormat(int,string)
+     *  @see #isADateFormat(int,String)
      *  @see #isInternalDateFormat(int)
      */
     public static boolean isCellInternalDateFormatted(HSSFCell cell) {
@@ -296,10 +312,10 @@ public class HSSFDateUtil
      * @exception IllegalArgumentException if date is invalid
      */
 
-    private static int absoluteDay(Calendar cal)
+    static int absoluteDay(Calendar cal, boolean use1904windowing)
     {
         return cal.get(Calendar.DAY_OF_YEAR)
-               + daysInPriorYears(cal.get(Calendar.YEAR));
+               + daysInPriorYears(cal.get(Calendar.YEAR), use1904windowing);
     }
 
     /**
@@ -307,14 +323,14 @@ public class HSSFDateUtil
      *
      * @return    days  number of days in years prior to yr.
      * @param     yr    a year (1900 < yr < 4000)
+     * @param use1904windowing 
      * @exception IllegalArgumentException if year is outside of range.
      */
 
-    private static int daysInPriorYears(int yr)
+    private static int daysInPriorYears(int yr, boolean use1904windowing)
     {
-        if (yr < 1900) {
+        if ((!use1904windowing && yr < 1900) || (use1904windowing && yr < 1900)) {
-            throw new IllegalArgumentException(
+            throw new IllegalArgumentException("'year' must be 1900 or greater");
-                "'year' must be 1900 or greater");
         }
         
         int yr1  = yr - 1;
@@ -323,7 +339,7 @@ public class HSSFDateUtil
                        + yr1 / 400 // plus years divisible by 400 
                        - 460;      // leap days in previous 1900 years
         
-        return 365 * (yr - 1900) + leapDays;
+        return 365 * (yr - (use1904windowing ? 1904 : 1900)) + leapDays;
     }
     
     // set HH:MM:SS fields of cal to 00:00:00:000

src/scratchpad/examples/src/org/apache/poi/hssf/eventusermodel/examples/XLS2CSVmra.java

@@ -283,7 +283,7 @@ public class XLS2CSVmra implements HSSFListener {
         		format = format.replaceAll("\\\\-","-");
         		
         		// Format as a date
-        		Date d = HSSFDateUtil.getJavaDate(value);
+        		Date d = HSSFDateUtil.getJavaDate(value, false);
         		DateFormat df = new SimpleDateFormat(format);
 	            return df.format(d);
         	} else {

src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Date.java

@@ -70,7 +70,7 @@ public class Date extends NumericFunction {
                 c.set(year, month, day, 0, 0, 0);
                 c.set(Calendar.MILLISECOND, 0);
                 
-                return new NumberEval(HSSFDateUtil.getExcelDate(c.getTime()));
+                return new NumberEval(HSSFDateUtil.getExcelDate(c.getTime(), false)); // XXX fix 1900/1904 problem
             }
         }
         

src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Day.java

@@ -46,7 +46,7 @@ srcCellRow, srcCellCol);
             if (ve instanceof NumericValueEval) {
                 NumericValueEval ne = (NumericValueEval) ve;
                 if (HSSFDateUtil.isValidExcelDate(ne.getNumberValue())) {
-                    java.util.Date d = HSSFDateUtil.getJavaDate(ne.getNumberValue());
+                    java.util.Date d = HSSFDateUtil.getJavaDate(ne.getNumberValue(), false); // XXX fix 1900/1904 problem
                     java.util.Calendar c = java.util.Calendar.getInstance();
                     c.setTime(d);
                     retval = new NumberEval(c.get(java.util.Calendar.DAY_OF_MONTH));

src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Month.java

@@ -50,7 +50,7 @@ public class Month extends NumericFunction {
             if (ve instanceof NumericValueEval) {
                 NumericValueEval ne = (NumericValueEval) ve;
                 if (HSSFDateUtil.isValidExcelDate(ne.getNumberValue())) {
-                    java.util.Date d = HSSFDateUtil.getJavaDate(ne.getNumberValue());
+                    java.util.Date d = HSSFDateUtil.getJavaDate(ne.getNumberValue(), false); // XXX fix 1900/1904 problem
                     retval = new NumberEval(d.getMonth()+1);
                 } else {
                     retval = ErrorEval.NUM_ERROR;

src/scratchpad/src/org/apache/poi/hssf/record/formula/functions/Year.java

@@ -51,7 +51,7 @@ public class Year extends NumericFunction {
             if (ve instanceof NumericValueEval) {
                 NumericValueEval ne = (NumericValueEval) ve;
                 if (HSSFDateUtil.isValidExcelDate(ne.getNumberValue())) {
-                    java.util.Date d = HSSFDateUtil.getJavaDate(ne.getNumberValue());
+                    java.util.Date d = HSSFDateUtil.getJavaDate(ne.getNumberValue(), false); // XXX fix 1900/1904 problem
                     retval = new NumberEval(d.getYear()+1900);
                 } else {
                     retval = ErrorEval.NUM_ERROR;

src/testcases/org/apache/poi/hssf/usermodel/TestHSSFCell.java

@@ -44,6 +44,7 @@ import java.util.GregorianCalendar;
  * paticular datatypes, etc.
  * @author Andrew C. Oliver (andy at superlinksoftware dot com)
  * @author  Dan Sherman (dsherman at isisph.com)
+ * @author Alex Jacoby (ajacoby at gmail.com)
  */
 
 public class TestHSSFCell
@@ -111,7 +112,7 @@ extends TestCase {
      *  is working properly. Conversion of the date is also an issue,
      *  but there's a separate unit test for that.
      */
-    public void testDateWindowing() throws Exception {
+     public void testDateWindowingRead() throws Exception {
          GregorianCalendar cal = new GregorianCalendar(2000,0,1); // Jan. 1, 2000
          Date date = cal.getTime();
          String path = System.getProperty("HSSF.testdata.path");
@@ -143,6 +144,70 @@ extends TestCase {
          stream.close();
      }
 
+     /**
+      * Checks that dates are properly written to both types of files:
+      * those with 1900 and 1904 date windowing.  Note that if the
+      * previous test ({@link #testDateWindowingRead}) fails, the
+      * results of this test are meaningless.
+      */
+      public void testDateWindowingWrite() throws Exception {
+          GregorianCalendar cal = new GregorianCalendar(2000,0,1); // Jan. 1, 2000
+          Date date = cal.getTime();
+          String path = System.getProperty("HSSF.testdata.path");
+
+          // first check a file with 1900 Date Windowing
+          String filename = path + "/1900DateWindowing.xls";
+          writeCell(filename, 0, (short) 1, date);          
+          assertEquals("Date from file using 1900 Date Windowing",
+                          date.getTime(),
+                          readCell(filename, 0, (short) 1).getTime());
+          
+          // now check a file with 1904 Date Windowing
+          filename = path + "/1904DateWindowing.xls";
+          writeCell(filename, 0, (short) 1, date);          
+          assertEquals("Date from file using 1900 Date Windowing",
+                          date.getTime(),
+                          readCell(filename, 0, (short) 1).getTime());
+      }
+
+      /**
+       * Sets cell value and writes file.
+       */
+      private void writeCell(String filename,
+     		 int rowIdx, short colIdx, Date date) throws Exception {
+          FileInputStream stream   = new FileInputStream(filename);
+          POIFSFileSystem fs       = new POIFSFileSystem(stream);
+          HSSFWorkbook    workbook = new HSSFWorkbook(fs);
+          HSSFSheet       sheet    = workbook.getSheetAt(0);
+          HSSFRow         row      = sheet.getRow(rowIdx);
+          HSSFCell        cell     = row.getCell(colIdx);
+          
+          if (cell == null) {
+        	  cell = row.createCell(colIdx);
+          }
+          cell.setCellValue(date);
+          
+          // Write the file
+          stream.close();
+          FileOutputStream oStream = new FileOutputStream(filename);
+          workbook.write(oStream);
+          oStream.close();
+      }
+      
+      /**
+       * Reads cell value from file.
+       */
+      private Date readCell(String filename,
+     		 int rowIdx, short colIdx) throws Exception {
+          FileInputStream stream   = new FileInputStream(filename);
+          POIFSFileSystem fs       = new POIFSFileSystem(stream);
+          HSSFWorkbook    workbook = new HSSFWorkbook(fs);
+          HSSFSheet       sheet    = workbook.getSheetAt(0);
+          HSSFRow         row      = sheet.getRow(rowIdx);
+          HSSFCell        cell     = row.getCell(colIdx);
+          return cell.getDateCellValue();
+      }
+      
     /**
      * Tests that the active cell can be correctly read and set
      */

src/testcases/org/apache/poi/hssf/usermodel/TestHSSFDateUtil.java

@@ -36,6 +36,8 @@ import org.apache.poi.poifs.filesystem.POIFSFileSystem;
  *
  * @author  Dan Sherman (dsherman at isisph.com)
  * @author  Hack Kampbjorn (hak at 2mba.dk)
+ * @author  Pavel Krupets (pkrupets at palmtreebusiness dot com)
+ * @author Alex Jacoby (ajacoby at gmail.com)
  * @version %I%, %G%
  */
 
@@ -47,6 +49,8 @@ public class TestHSSFDateUtil
 	public static final int CALENDAR_FEBRUARY = 1;
 	public static final int CALENDAR_MARCH = 2;
 	public static final int CALENDAR_APRIL = 3;
+	public static final int CALENDAR_JULY = 6;
+    public static final int CALENDAR_OCTOBER = 9;
     
     public TestHSSFDateUtil(String s)
     {
@@ -67,10 +71,10 @@ public class TestHSSFDateUtil
             GregorianCalendar date      = new GregorianCalendar(2002, 0, 1,
                     hour, 1, 1);
             double            excelDate =
-                    HSSFDateUtil.getExcelDate(date.getTime());
+                    HSSFDateUtil.getExcelDate(date.getTime(), false);
 
             assertEquals("Checking hour = " + hour, date.getTime().getTime(),
-                    HSSFDateUtil.getJavaDate(excelDate).getTime());
+                    HSSFDateUtil.getJavaDate(excelDate, false).getTime());
         }
 
         // check 1900 and 1904 date windowing conversions
@@ -99,7 +103,7 @@ public class TestHSSFDateUtil
     public void testExcelConversionOnDSTStart() {
         TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen");
         TimeZone.setDefault(cet);
-        Calendar cal = new GregorianCalendar(2004, Calendar.MARCH, 28);
+        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
@@ -110,7 +114,7 @@ public class TestHSSFDateUtil
 
             cal.set(Calendar.HOUR_OF_DAY, hour);
             Date javaDate = cal.getTime();
-            double excelDate = HSSFDateUtil.getExcelDate(javaDate);
+            double excelDate = HSSFDateUtil.getExcelDate(javaDate, false);
             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",
@@ -118,7 +122,7 @@ public class TestHSSFDateUtil
                     differenceInHours);
             assertEquals("Checking " + hour + " hour on Daylight Saving Time start date",
                     javaDate.getTime(),
-                    HSSFDateUtil.getJavaDate(excelDate).getTime());
+                    HSSFDateUtil.getJavaDate(excelDate, false).getTime());
         }
     }
 
@@ -129,8 +133,8 @@ public class TestHSSFDateUtil
     public void testJavaConversionOnDSTStart() {
         TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen");
         TimeZone.setDefault(cet);
-        Calendar cal = new GregorianCalendar(2004, Calendar.MARCH, 28);
+        Calendar cal = new GregorianCalendar(2004, CALENDAR_MARCH, 28);
-        double excelDate = HSSFDateUtil.getExcelDate(cal.getTime());
+        double excelDate = HSSFDateUtil.getExcelDate(cal.getTime(), false);
         double oneHour = 1.0 / 24;
         double oneMinute = oneHour / 60;
         for (int hour = 0; hour < 24; hour++, excelDate += oneHour) {
@@ -142,10 +146,10 @@ public class TestHSSFDateUtil
             }
 
             cal.set(Calendar.HOUR_OF_DAY, hour);
-            Date javaDate = HSSFDateUtil.getJavaDate(excelDate);
+            Date javaDate = HSSFDateUtil.getJavaDate(excelDate, false);
             assertEquals("Checking " + hour + " hours on Daylight Saving Time start date",
                     excelDate,
-                    HSSFDateUtil.getExcelDate(javaDate), oneMinute);
+                    HSSFDateUtil.getExcelDate(javaDate, false), oneMinute);
         }
     }
 
@@ -156,11 +160,11 @@ public class TestHSSFDateUtil
     public void testExcelConversionOnDSTEnd() {
         TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen");
         TimeZone.setDefault(cet);
-        Calendar cal = new GregorianCalendar(2004, Calendar.OCTOBER, 31);
+        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 excelDate = HSSFDateUtil.getExcelDate(javaDate, false);
             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",
@@ -168,7 +172,7 @@ public class TestHSSFDateUtil
                     differenceInHours);
             assertEquals("Checking " + hour + " hour on Daylight Saving Time start date",
                     javaDate.getTime(),
-                    HSSFDateUtil.getJavaDate(excelDate).getTime());
+                    HSSFDateUtil.getJavaDate(excelDate, false).getTime());
         }
     }
 
@@ -179,16 +183,16 @@ public class TestHSSFDateUtil
     public void testJavaConversionOnDSTEnd() {
         TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen");
         TimeZone.setDefault(cet);
-        Calendar cal = new GregorianCalendar(2004, Calendar.OCTOBER, 31);
+        Calendar cal = new GregorianCalendar(2004, CALENDAR_OCTOBER, 31);
-        double excelDate = HSSFDateUtil.getExcelDate(cal.getTime());
+        double excelDate = HSSFDateUtil.getExcelDate(cal.getTime(), false);
         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);
+            Date javaDate = HSSFDateUtil.getJavaDate(excelDate, false);
             assertEquals("Checking " + hour + " hours on Daylight Saving Time start date",
                     excelDate,
-                    HSSFDateUtil.getExcelDate(javaDate), oneMinute);
+                    HSSFDateUtil.getExcelDate(javaDate, false), oneMinute);
         }
     }
     
@@ -315,23 +319,36 @@ public class TestHSSFDateUtil
     }
     
     public void testDateBug_2Excel() {
-        assertEquals(59.0, HSSFDateUtil.getExcelDate(createDate(1900, CALENDAR_FEBRUARY, 28)), 0.00001);
+        assertEquals(59.0, HSSFDateUtil.getExcelDate(createDate(1900, CALENDAR_FEBRUARY, 28), false), 0.00001);
-        assertEquals(61.0, HSSFDateUtil.getExcelDate(createDate(1900, CALENDAR_MARCH, 1)), 0.00001);
+        assertEquals(61.0, HSSFDateUtil.getExcelDate(createDate(1900, CALENDAR_MARCH, 1), false), 0.00001);
 
-        assertEquals(37315.00, HSSFDateUtil.getExcelDate(createDate(2002, CALENDAR_FEBRUARY, 28)), 0.00001);
+        assertEquals(37315.00, HSSFDateUtil.getExcelDate(createDate(2002, CALENDAR_FEBRUARY, 28), false), 0.00001);
-        assertEquals(37316.00, HSSFDateUtil.getExcelDate(createDate(2002, CALENDAR_MARCH, 1)), 0.00001);
+        assertEquals(37316.00, HSSFDateUtil.getExcelDate(createDate(2002, CALENDAR_MARCH, 1), false), 0.00001);
-        assertEquals(37257.00, HSSFDateUtil.getExcelDate(createDate(2002, CALENDAR_JANUARY, 1)), 0.00001);
+        assertEquals(37257.00, HSSFDateUtil.getExcelDate(createDate(2002, CALENDAR_JANUARY, 1), false), 0.00001);
-        assertEquals(38074.00, HSSFDateUtil.getExcelDate(createDate(2004, CALENDAR_MARCH, 28)), 0.00001);
+        assertEquals(38074.00, HSSFDateUtil.getExcelDate(createDate(2004, CALENDAR_MARCH, 28), false), 0.00001);
     }
     
     public void testDateBug_2Java() {
-        assertEquals(createDate(1900, Calendar.FEBRUARY, 28), HSSFDateUtil.getJavaDate(59.0));
+        assertEquals(createDate(1900, CALENDAR_FEBRUARY, 28), HSSFDateUtil.getJavaDate(59.0, false));
-        assertEquals(createDate(1900, Calendar.MARCH, 1), HSSFDateUtil.getJavaDate(61.0));
+        assertEquals(createDate(1900, CALENDAR_MARCH, 1), HSSFDateUtil.getJavaDate(61.0, false));
         
-        assertEquals(createDate(2002, Calendar.FEBRUARY, 28), HSSFDateUtil.getJavaDate(37315.00));
+        assertEquals(createDate(2002, CALENDAR_FEBRUARY, 28), HSSFDateUtil.getJavaDate(37315.00, false));
-        assertEquals(createDate(2002, Calendar.MARCH, 1), HSSFDateUtil.getJavaDate(37316.00));
+        assertEquals(createDate(2002, CALENDAR_MARCH, 1), HSSFDateUtil.getJavaDate(37316.00, false));
-        assertEquals(createDate(2002, Calendar.JANUARY, 1), HSSFDateUtil.getJavaDate(37257.00));
+        assertEquals(createDate(2002, CALENDAR_JANUARY, 1), HSSFDateUtil.getJavaDate(37257.00, false));
-        assertEquals(createDate(2004, Calendar.MARCH, 28), HSSFDateUtil.getJavaDate(38074.00));
+        assertEquals(createDate(2004, CALENDAR_MARCH, 28), HSSFDateUtil.getJavaDate(38074.00, false));
+    }
+    
+    public void testDate1904() {
+        assertEquals(createDate(1904, CALENDAR_JANUARY, 2), HSSFDateUtil.getJavaDate(1.0, true));
+        assertEquals(createDate(1904, CALENDAR_JANUARY, 1), HSSFDateUtil.getJavaDate(0.0, true));
+        assertEquals(0.0, HSSFDateUtil.getExcelDate(createDate(1904, CALENDAR_JANUARY, 1), true), 0.00001);
+        assertEquals(1.0, HSSFDateUtil.getExcelDate(createDate(1904, CALENDAR_JANUARY, 2), true), 0.00001);
+        
+        assertEquals(createDate(1998, CALENDAR_JULY, 5), HSSFDateUtil.getJavaDate(35981, false));
+        assertEquals(createDate(1998, CALENDAR_JULY, 5), HSSFDateUtil.getJavaDate(34519, true));
+        
+        assertEquals(35981.0, HSSFDateUtil.getExcelDate(createDate(1998, CALENDAR_JULY, 5), false), 0.00001);
+        assertEquals(34519.0, HSSFDateUtil.getExcelDate(createDate(1998, CALENDAR_JULY, 5), true), 0.00001);
     }
     
     private Date createDate(int year, int month, int day) {
@@ -341,10 +358,21 @@ public class TestHSSFDateUtil
         return c.getTime();
     }
     
+    /**
+     * Check if HSSFDateUtil.getAbsoluteDay works as advertised.
+     */
+    public void testAbsoluteDay() {
+        // 1 Jan 1900 is 1 day after 31 Dec 1899
+        GregorianCalendar calendar = new GregorianCalendar(1900, 0, 1);
+        assertEquals("Checking absolute day (1 Jan 1900)", 1, HSSFDateUtil.absoluteDay(calendar, false));
+        // 1 Jan 1901 is 366 days after 31 Dec 1899
+        calendar = new GregorianCalendar(1901, 0, 1);
+        assertEquals("Checking absolute day (1 Jan 1901)", 366, HSSFDateUtil.absoluteDay(calendar, false));
+    }
+    
     public static void main(String [] args) {
         System.out
                 .println("Testing org.apache.poi.hssf.usermodel.TestHSSFDateUtil");
         junit.textui.TestRunner.run(TestHSSFDateUtil.class);
     }
 }
-

src/testcases/org/apache/poi/hssf/usermodel/TestReadWriteChart.java

@@ -63,7 +63,7 @@ public class TestReadWriteChart
         //System.out.println("first assertion for date");
         assertEquals(new GregorianCalendar(2000, 0, 1, 10, 51, 2).getTime(),
                      HSSFDateUtil
-                         .getJavaDate(firstCell.getNumericCellValue()));
+                         .getJavaDate(firstCell.getNumericCellValue(), false));
         HSSFRow  row  = sheet.createRow(( short ) 15);
         HSSFCell cell = row.createCell(( short ) 1);