Q:
How would I limit ToXod conversions to no more then 30 seconds?
A:
You can switch to one of the ToXod methods that return a filter. Then you can exit the reading loop whenever you like.
http://www.pdftron.com/pdfnet/docs/PDFNetJava/pdftron/PDF/Convert.html#toXod%28pdftron.SDF.Doc,%20pdftron.PDF.Convert.XODOutputOptions%29
This forum post shows how to convert this way
https://groups.google.com/d/msg/pdfnet-sdk/3UvGjkp0cr8/lbtwOdyTs2EJ
That being said, you might not want to do this, as files might just be taking a long time. Using the ToXod that returns a filter, would allow you to monitor the conversion. Note, that the first read will block the longest, as some full document pre-processing has to occur here, so either don’t time the first read, or give it an order of magnitude longer time, then the subsequent reads.