[antlr-interest] Can I restart lexing from definite position in document?

[P.N.]

Hello!

Just want to know, if it's possible to restart lexing in a big file. 
Say, e.g. the file might be of 20MB or more (okay, that's not good 
programming style, but's not the question here ;-) ), and I'd change 
sth. at the end of the file - would I need to do lexing from start 
again, or is there a chance to do it only for the last characters? 
Probably using org.antlr.runtime.RecognizerSharedState? How should I use it?

Kind regards

Peter