apache POI createFormulaListConstraint results in “Unreadable content” when opening excel

Question

Like the title says: when I try to add a DataValidationConstraint using XSSFDataValidationHelper's method createFormulaListConstraint("...") the excel file's content is incorrect according to the pop-up when I try to open it in MS Excel.

When I create a data validation using excel this formula works as expected:

=OFFSET(Sites!$A$2;0;0;COUNTA(Sites!$A:$A)- 1;1)

Now I am trying to do the same using apache poi 3.8:

XSSFDataValidationConstraint siteNamesConstraint = (XSSFDataValidationConstraint) dvHelper.createFormulaListConstraint("=OFFSET('Sites'!$A$2;0;0;COUNTA('Sites'!$A:$A)- 1;1)");

I get the error when opening the excel file.

I have tried other formulas as well:

• =OFFSET('Sites'!$A$2;0;0;COUNTA('Sites'!$A:$A)- 1;1) (with '' around the sheet names, with '=')
• OFFSET('Sites'!$A$2;0;0;COUNTA('Sites'!$A:$A)- 1;1) (with '' around the sheet names, no '=')
• =OFFSET(Sites!$A$2;0;0;COUNTA(Sites!$A:$A)- 1;1) (no '' around the names, with '=')
• OFFSET(Sites!$A$2;0;0;COUNTA(Sites!$A:$A)- 1;1) (no '' around the names, no '=')

None of these seem to be correct.

What I had before this was just 'Sites'!$A$2:$A$100 and this worked but it included blank values in the result which is not what I need.

Am I doing something wrong here or is there another way not to include blank values in the list?

Answer 1

Sigh, I just found the solution 5 minutes after posting this question.

When typing formulas in excel ";" is used as a delimiter in functions, in POI however the delimiter is ",".

I have discovered this when trying the following code:

Name namedRange = wb.createName();
namedRange.setNameName("sites");
namedRange.setRefersToFormula("OFFSET('Sites'!$A$2,0,0,COUNTA('Sites'!$A:$A)- 1,1)");

And then referring to it with:

(XSSFDataValidationConstraint) dvHelper.createFormulaListConstraint("sites");

setRefersToFormula of the 'Name' class provides much better error handling and displayed what was wrong with my formula ("," expected but ";" found).