Added methods for date reading and writing on HSSFCell.

git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/trunk@352092 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -71,6 +71,8 @@ import org.apache.poi.hssf.record.BlankRecord;
 import org.apache.poi.hssf.record.BoolErrRecord;
 import org.apache.poi.hssf.record.ExtendedFormatRecord;
 
+import java.util.Date;
+
 /**
  * High level representation of a cell in a row of a spreadsheet.
  * Cells can be numeric, formula-based or string-based (text).  The cell type
@@ -608,11 +610,9 @@ public class HSSFCell
      *        precalculated value, for numerics we'll set its value. For other types we
      *        will change the cell to a numeric cell and set its value.
      */
-
     public void setCellValue(double value)
     {
-        if ((cellType != CELL_TYPE_NUMERIC)
+        if ((cellType != CELL_TYPE_NUMERIC) && (cellType != CELL_TYPE_FORMULA))
-                && (cellType != CELL_TYPE_FORMULA))
         {
             setCellType(CELL_TYPE_NUMERIC, false);
         }
@@ -620,6 +620,19 @@ public class HSSFCell
         cellValue = value;
     }
 
+    /**
+     * set a date value for the cell. Excel treats dates as numeric so you will need to format the cell as
+     * a date.
+     *
+     * @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 other types we
+     *        will change the cell to a numeric cell and set its value.
+     */
+    public void setCellValue(Date value)
+    {
+        setCellValue(HSSFDateUtil.getExcelDate(value));
+    }
+
     /**
      * set a string value for the cell.
      *
@@ -686,6 +699,34 @@ public class HSSFCell
         return cellValue;
     }
 
+    /**
+     * get the value of the cell as a date.  For strings we throw an exception.
+     * For blank cells we return a null.
+     */
+    public Date getDateCellValue()
+    {
+        if (cellType == CELL_TYPE_BLANK)
+        {
+            return null;
+        }
+        if (cellType == CELL_TYPE_STRING)
+        {
+            throw new NumberFormatException(
+                "You cannot get a date value from a String based cell");
+        }
+        if (cellType == CELL_TYPE_BOOLEAN)
+        {
+            throw new NumberFormatException(
+                "You cannot get a date value from a boolean cell");
+        }
+        if (cellType == CELL_TYPE_ERROR)
+        {
+            throw new NumberFormatException(
+                "You cannot get a date value from an error cell");
+        }
+        return HSSFDateUtil.getJavaDate(cellValue);
+    }
+
     /**
      * get the value of the cell as a string - for numeric cells we throw an exception.
      * For blank cells we return an empty string.

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

@@ -135,6 +135,32 @@ public class TestCellStyle
         // assert((s.getLastRowNum() == 99));
     }
 
+    /**
+     * Tests that is creating a file with a date works correctly.
+     */
+    public void testDataStyle()
+            throws Exception
+    {
+        File             file = File.createTempFile("testWriteSheetStyleDate",
+                                                    ".xls");
+        FileOutputStream out  = new FileOutputStream(file);
+        HSSFWorkbook     wb   = new HSSFWorkbook();
+        HSSFSheet        s    = wb.createSheet();
+        HSSFCellStyle    cs   = wb.createCellStyle();
+        HSSFRow row = s.createRow((short)0);
+        HSSFCell cell = row.createCell((short)1);
+        cs.setDataFormat(HSSFDataFormat.getFormat("m/d/yy"));
+        cell.setCellStyle(cs);
+        cell.setCellValue(new Date());
+        wb.write(out);
+        out.close();
+
+        assertEquals("FILE LENGTH ", 5632, file.length());
+        assertEquals("LAST ROW ", 0, s.getLastRowNum());
+        assertEquals("FIRST ROW ", 0, s.getFirstRowNum());
+
+    }
+
     /**
      * TEST NAME:  Test Write Sheet Style <P>
      * OBJECTIVE:  Test that HSSF can create a simple spreadsheet with numeric and string values and styled with colors