Jakarta-Poi and Inline::Java: problems transfering large arrays from java to perl

[Heiko Klein]

Hi,

I have to read large Excel-files (5sheet, 4000rows, 50columns) with 
perl. Misereably, the Spreadsheet::ParseExcel modules is really slow and 
memory hungry on this (> 5min parsing, > 250MB memory).

Therefore I've been looking around and found the nice jakarta POI 
project, handling exactly the same problem, but in Java. Parsing is 
quite fast (~30s, 100MB) on the Java process. It was next to no problem 
to attach this to perl using Inline::Java.

My problem is getting the data back from java to perl. I tried to 
transfer the data at once, so I created a String[][] per sheet and get 
it by a function to perl. But when I try to use the values, it is still 
accessing the Java process, and while parsing takes only 30s, accessing 
each value of my String[][] of one sheet takes ~2min (about 70% perl and 
30% java cpu usage (top)). Using JNI reduced the time but it's still 
above 1min.

Has anybody a good idea how to transfer the data with only one call to 
the JVM? Any ideas about other projects reading Excel-files by Perl are 
welcome, too. (Dropping excel is not possible, misereably.)

Best regards,

Heiko