Lucene writing from web request

I'm looking to implement Lucene for a webapp I'm working on and I'm more or less looking for a "best practice".

What I'm trying to achieve is to have a web request come in (via an ajax post) and add a doc to my lucene index with the information posted.

However, what i'm unsure of is: Can i run lucene in the context of a web request or do i need to run it separately and have my requests write to a folder (which the separate lucene would monitor and load docs based on the file)

I've been doing allot of searching into how to achieve this but i'm not finding many/any results so i think i may be totally off here