Right, thanks for opening this for 6.

There are also some discussions about potentially leaving the high-level concept around, maybe replacing the real Filter with some other helpers:
http://mail-archives.apache.org/mod_mbox/lucene-java-user/201601.mbox/%3C008201d14f6e%2493562bf0%24ba0283d0%24%40thetaphi.de%3E