Purpose / importance of the file modification date methods in Lucene's Directory?

Question

I've built a Lucene Directory implementation for jdbm, an embedded Java database. Part of the Directory API are two methods related to "file" modification dates: touchFile and fileModified (javadoc). My question is, what is the purpose of these methods? I've searched the entire Lucene core source tree, and found no usage of these methods at all.

FWIW, my interest is the fact that I'd like to not bother tracking mod dates, given that I'm using an embedded datastore, and such metadata isn't "free" as it is in a regular filesystem.

Answer 1

I confirmed via the lucene-users mailing list that the methods in question are not used by any Lucene codebase, but that it's possible (though very unlikely, it seems to me) that applications using one's Directory implementation would expect those methods to function properly. shrug