Does pdf ignore leading spaces?

[Jens Kühnberger <Ku...@web.de>]

  Hi,

I got the problem that one of my servlets creates a very big pdf from 
database, which can take several minutes. To not waist ressources, I 
want to detect if the user pressed the stop button. The only way to do 
that, as far as I know, is to stream a space or a bit and check if there 
is an IOException. So, does a pdf file ignore leading spaces or bits at 
the beginning or is it impossible to check if the user pressed the stop 
button?