While working on bug 61148 I found that getCellType() and setCellErrorValue() in SXSSFCell are doing different things than the ones in XSSFCell, tried to fix this by mimicking functionality of XSSF in SXSSF as well.

Reformating some small things as well.

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1808874 13f79535-47bb-0310-9956-ffa450edef68

src/ooxml/java/org/apache/poi/xssf/streaming/SXSSFCell.java

@@ -124,14 +124,21 @@ public class SXSSFCell implements Cell {
         ensureType(cellType);
     }
 
+    private boolean isFormulaCell() {
+        return _value instanceof FormulaValue;
+    }
+
     /**
      * Return the cell type.
      *
      * @return the cell type
      */
     @Override
-    public CellType getCellType()
-    {
+    public CellType getCellType() {
+        if (isFormulaCell()) {
+            return CellType.FORMULA;
+        }
+
         return _value.getType();
     }
     
@@ -158,7 +165,7 @@ public class SXSSFCell implements Cell {
      */
     @Override
     public CellType getCachedFormulaResultType() {
-        if (_value.getType() != CellType.FORMULA) {
+        if (!isFormulaCell()) {
             throw new IllegalStateException("Only formula cells have cached results");
         }
 
@@ -497,14 +504,19 @@ public class SXSSFCell implements Cell {
      * @see org.apache.poi.ss.usermodel.FormulaError
      */
     @Override
-    public void setCellErrorValue(byte value)
-    {
-        ensureType(CellType.ERROR);
-        if(_value.getType()==CellType.FORMULA)
+    public void setCellErrorValue(byte value) {
+        // for formulas, we want to keep the type and only have an ERROR as formula value
+        if(_value.getType()==CellType.FORMULA) {
+            // ensure that the type is "ERROR"
+            setFormulaType(CellType.ERROR);
+
+            // populate the value
             ((ErrorFormulaValue) _value).setPreEvaluatedValue(value);
-        else
+        } else {
+            ensureType(CellType.ERROR);
             ((ErrorValue) _value).setValue(value);
         }
+    }
 
     /**
      * Get the value of the cell as a boolean.

src/ooxml/testcases/org/apache/poi/xssf/streaming/TestSXSSFCell.java

@@ -20,6 +20,7 @@
 package org.apache.poi.xssf.streaming;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 
 import java.io.IOException;
 
@@ -71,6 +72,7 @@ public class TestSXSSFCell extends BaseTestXCell {
             XSSFCell xCell = xwb.getSheetAt(0).getRow(0).getCell(0);
 
             CTRst is = xCell.getCTCell().getIs();
+            assertNotNull(is);
             XmlCursor c = is.newCursor();
             c.toNextToken();
             String t = c.getAttributeText(new QName("http://www.w3.org/XML/1998/namespace", "space"));

src/testcases/org/apache/poi/ss/usermodel/BaseTestCell.java

@@ -1014,4 +1014,46 @@ public abstract class BaseTestCell {
 
         wb.close();
     }
+
+    @Test
+    public void testSetErrorValue() throws Exception {
+        try (Workbook wb = _testDataProvider.createWorkbook()) {
+            Sheet sheet = wb.createSheet();
+            Row row = sheet.createRow(0);
+            Cell cell = row.createCell(0);
+
+            cell.setCellFormula("A2");
+            cell.setCellErrorValue(FormulaError.NAME.getCode());
+
+            assertEquals(CellType.FORMULA, cell.getCellType());
+            assertEquals(CellType.ERROR, cell.getCachedFormulaResultType());
+            assertEquals("A2", cell.getCellFormula());
+            try {
+                cell.getNumericCellValue();
+                fail("Should catch exception here");
+            } catch (IllegalStateException e) {
+                // expected here
+            }
+            try {
+                cell.getStringCellValue();
+                fail("Should catch exception here");
+            } catch (IllegalStateException e) {
+                // expected here
+            }
+            try {
+                cell.getRichStringCellValue();
+                fail("Should catch exception here");
+            } catch (IllegalStateException e) {
+                // expected here
+            }
+            try {
+                cell.getDateCellValue();
+                fail("Should catch exception here");
+            } catch (IllegalStateException e) {
+                // expected here
+            }
+            assertEquals(FormulaError.NAME.getCode(), cell.getErrorCellValue());
+            assertNull(cell.getHyperlink());
+        }
+    }
 }