Change Worksheet function visibility from private to protected in ord…

…er to class extending. We have created small package on top of the Spout for support cell number format and per cell styles.

src/Spout/Writer/XLSX/Internal/Worksheet.php

@@ -159,7 +159,7 @@ public function addRow($dataRow, $style)
      *          Example $dataRow = ['data1', 1234, null, '', 'data5'];
      * @return bool Whether the given row is empty
      */
-    private function isEmptyRow($dataRow)
+    protected function isEmptyRow($dataRow)
     {
         $numCells = count($dataRow);
         // using "reset()" instead of "$dataRow[0]" because $dataRow can be an associative array
@@ -176,7 +176,7 @@ private function isEmptyRow($dataRow)
      * @throws \Box\Spout\Common\Exception\IOException If the data cannot be written
      * @throws \Box\Spout\Common\Exception\InvalidArgumentException If a cell value's type is not supported
      */
-    private function addNonEmptyRow($dataRow, $style)
+    protected function addNonEmptyRow($dataRow, $style)
     {
         $cellNumber = 0;
         $rowIndex = $this->lastWrittenRowIndex + 1;
@@ -207,7 +207,7 @@ private function addNonEmptyRow($dataRow, $style)
      * @return string
      * @throws InvalidArgumentException If the given value cannot be processed
      */
-    private function getCellXML($rowIndex, $cellNumber, $cellValue, $styleId)
+    protected function getCellXML($rowIndex, $cellNumber, $cellValue, $styleId)
     {
         $columnIndex = CellHelper::getCellIndexFromColumnIndex($cellNumber);
         $cellXML = '<c r="' . $columnIndex . $rowIndex . '"';
@@ -241,7 +241,7 @@ private function getCellXML($rowIndex, $cellNumber, $cellValue, $styleId)
      * @return string The XML fragment representing the cell
      * @throws InvalidArgumentException If the string exceeds the maximum number of characters allowed per cell
      */
-    private function getCellXMLFragmentForNonEmptyString($cellValue)
+    protected function getCellXMLFragmentForNonEmptyString($cellValue)
     {
         if ($this->stringHelper->getStringLength($cellValue) > self::MAX_CHARACTERS_PER_CELL) {
             throw new InvalidArgumentException('Trying to add a value that exceeds the maximum number of characters allowed in a cell (32,767)');