Apache POI: Why Is a Row Missing When I use shiftRows? - scala

Question

I'm shifting the rows in an excel sheet and inserting a new row at the beginning of the sheet. However, regardless of how many rows I shift and insert, I seem to be ending up with one less row than I should be.
import org.apache.poi.ss.usermodel.Row
import Row.MissingCellPolicy._
import org.apache.poi.ss.usermodel.Sheet
import org.apache.poi.ss.usermodel.Workbook
import org.apache.poi.ss.util.CellRangeAddress
import org.apache.poi.ss.util.WorkbookUtil.createSafeSheetName
import org.apache.poi.xssf.usermodel.XSSFWorkbook
def shiftAndInsertRow(sheet: Sheet) = {
val rowInsertionPoint = 0
// shift all the rows down
val lastRowNum = sheet.getLastRowNum
println(s"Last row is $lastRowNum")
val debugRow1 = sheet.getRow(rowInsertionPoint)
val debugCell1 = debugRow1.getCell(0)
// let's get a play-by-play of what's being attempted
println(s"Current value in row $rowInsertionPoint is " +
s"${debugCell1.getNumericCellValue}")
println(s"Shifting rows $rowInsertionPoint and below down one row")
sheet.shiftRows(rowInsertionPoint, lastRowNum, 1, true, true)
val debugRow2 = sheet.getRow(rowInsertionPoint + 1)
val debugCell2 = debugRow2.getCell(0)
println(s"Current value in row ${rowInsertionPoint + 1} is now " +
s"${debugCell2.getNumericCellValue}")
println(s"Creating new row at $rowInsertionPoint in sheet")
// create the new row
val newRow = sheet.createRow(rowInsertionPoint)
// set the field ID of the row
val newCell = newRow.getCell(0, CREATE_NULL_AS_BLANK)
println(s"Inserting value $lastRowNum at $rowInsertionPoint in sheet")
newCell.setCellValue(lastRowNum)
println()
}
val workbook = new XSSFWorkbook()
val sheet = workbook.createSheet(createSafeSheetName("Test 1"))
val rowNum = 0
val cellValue = -1
println(s"Creating new row at $rowNum in sheet")
// create the new row
val row = sheet.createRow(rowNum)
// set the field ID of the row
val cell = row.getCell(0, CREATE_NULL_AS_BLANK)
println(s"Inserting value $cellValue at $rowNum in sheet")
cell.setCellValue(cellValue)
println()
// insert a second row
shiftAndInsertRow(sheet)
// and a third
shiftAndInsertRow(sheet)
workbook.write(new java.io.FileOutputStream("out/test.xlsx"))
The above code creates a spreadsheet with only two rows instead of three. What am I missing?

Answer 1

I think your code is fine, it looks to me like this is a bug in apache-poi. It works for me on version 3.17 but breaks if I upgrade to 4.0.0.
As far as I can tell, the row num is being updated correctly, but the reference (cell.getReference) is not.
I would suggest trying to find if the bug has already been reported here https://bz.apache.org/bugzilla/buglist.cgi?product=POI and if not, filing a new bug report.
In the meantime, you could perhaps try this workaround which seems to do the trick for me. It calls updateCellReferencesForShifting on every cell in the spreadsheet.
import scala.collection.JavaConverters._
for {
row <- sheet.rowIterator().asScala.toList
cell <- row.cellIterator().asScala.toList
} yield cell.asInstanceOf[XSSFCell].updateCellReferencesForShifting("")
Place this block of code right after your call to shiftRows. No guarantees that it's not going to break something else though, so use with caution!