Bug 53517

Summary: Row iteration on formatted Sheet raise Nullpointer Exception
Product: POI Reporter: Ralf Rublack <info>
Component: XSSFAssignee: POI Developers List <dev>
Severity: normal    
Priority: P2    
Version: 3.7-FINAL   
Target Milestone: ---   
Hardware: PC   
OS: All   
Attachments: formatted Template

Description Ralf Rublack 2012-07-07 11:21:17 UTC
Created attachment 29037 [details]
formatted Template

If using a formatted sheet as template and e.g setting row.height at Row 510
raise nullpointer exception when iterate over rows using LastRowNr.

for (int i=0; i <= workbook.getSheet("template").getLastRowNum(); i++)
Row actRow = workbook.getSheet("template").getRow(i);

because it looks like a empty sheet hast normally only 500 rows and formatting 
a row after 500 at this row to the row list. 
Now the row treeMap has 501 entries, with keys 0 to 499 and the additional key 510 
from the formatted row as entry 501 .
Calling workbook.getSheetAt(0).getLastRowNum() get the key 510 and iterate like above raise Nullpointer in workbook.getSheetAt(0).getRow(i) because keys 500 to 509 are not in the treeMap.

I put the template file as attachment
Comment 1 Nick Burch 2012-07-07 11:37:00 UTC
The Excel file format is a sparse format. If rows aren't used, and have never been used, then they'll never be present in the file

If you only want defined rows, then use the RowIterator on a sheet. If you you iterate between the FirstRowNum and LastRowNum, then you need to check that the row isn't null before using it. See the website for more info on all of this
Comment 2 Ralf Rublack 2012-07-07 13:26:56 UTC
Hi Nick,
thx for your hint