nsIUnicharStreamListener

Hi, I'm hoping someone can point me to some sample code or give me a
little feedback. I'm building a Java application with Mozilla embedded
using XPCOM. I'm pretty sure I need to use nsIUnicharStreamListener to
do part of what I want to do. I've written a class that implements the
nsIUnicharStreamListener interface, but I'm at a total loss as to what
to do from there. I don't understand how to hook it into the browser
so that it gets called and feeds me the data.

Any help or a pointer to sample code would be really helpful at this
point.

Thanks!
==Andrew