| Summary: | HSSFRow should be backed by a Linked List | ||
|---|---|---|---|
| Product: | POI | Reporter: | Joe Pollard <joeslice> |
| Component: | HSSF | Assignee: | POI Developers List <dev> |
| Status: | RESOLVED WORKSFORME | ||
| Severity: | normal | CC: | joeslice |
| Priority: | P2 | ||
| Version: | 3.5-dev | ||
| Target Milestone: | --- | ||
| Hardware: | PC | ||
| OS: | Linux | ||
| Attachments: | Cells is now backed by a linked list. | ||
Thanks for the patch. Adding the method insertCell() to HSSFRow is a good idea. I'm not sure however that the proposed optimisation is appropriate, given that it seems to be motivated by a method that isn't present yet. I did a quick performance test, running the existing 997 junits six times, with and without the change. My results show a degradation of about 5% (times in seconds): poi trunk (8.781, 9.375, 8.453, 8.453, 8.484, 8.453) with change (9.078, 9.156, 9.125, 9.203, 9.047, 9.094) Hopefully the POI unit tests are a fair representation of general POI usage (they *should* be, because many were based on example code posted to bugzilla). I guess HSSFRow was written assuming that client code would generally use random access to read the cells. If you could re-do the patch just for HSSFRow.insertCell(), that is likely to get applied. However the optimisation needs more justification/tweaking. This fix became no longer necessary after 46266 was patched. Thanks for the consideration, I'm marking this as resolved, as it's not really an issue anymore. |
Created attachment 23848 [details] Cells is now backed by a linked list. Currently HSSFRow uses an array that occasionally needs to be resized, and inserting a column in the middle is not as efficient as it could be. Please see the attached patch. I've also added a method insertCell to make it more convenient to insert into the middle of a row.