[bug-66039] add more javadoc about setCellFormulaValidation

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1900383 13f79535-47bb-0310-9956-ffa450edef68

poi-ooxml/src/main/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java

@@ -2485,6 +2485,7 @@ public class XSSFWorkbook extends POIXMLDocument implements Workbook, Date1904Su
 
     /**
      * Whether a call to {@link XSSFCell#setCellFormula(String)} will validate the formula or not.
+     * When enabled (which is the default), this option can lead to formulas being modified by POI formula renderer.
      *
      * @param value true if the application will validate the formula is correct
      * @since 3.17
@@ -2495,6 +2496,7 @@ public class XSSFWorkbook extends POIXMLDocument implements Workbook, Date1904Su
 
     /**
      * Whether a call to {@link XSSFCell#setCellFormula(String)} will validate the formula or not.
+     * When enabled (which is the default), this option can lead to formulas being modified by POI formula renderer.
      *
      * @since 3.17
      */

poi/src/main/java/org/apache/poi/ss/usermodel/Cell.java

@@ -232,10 +232,14 @@ public interface Cell {
      *
      * <p>If the cell was blank, sets value to 0. Otherwise, preserves the value as precalculated.</p>
      *
+     * <p></p>In XSSF implementation, there is a <code>XSSFWorkbook.setCellFormulaValidation(boolean)</code>
+     * setting that can validate (but also in some cases, reformat) the formula.</p>
+     * 
      * @param formula the formula to set, e.g. <code>"SUM(C4:E4)"</code>.
      * If the argument is <code>null</code> then the current formula is removed.
      *
      * @see Cell#removeFormula
+     * @see Workbook#setForceFormulaRecalculation(boolean) 
      * @throws IllegalStateException if this cell is a part of an array formula group containing other cells
      * @throws FormulaParseException if the formula has incorrect syntax or is otherwise invalid
      */