The facet module contains two interfaces TaxonomyWriter and TaxonomyReader, with two implementations Lucene*. We've never actually implemented two TaxonomyWriters/Readers, so I'm not sure if these interfaces are useful anymore. Therefore I'd like to propose that we do either of the following:
- Remove the interfaces and remove the Lucene part from the implementation classes (to end up with TW/TR impls). Or,
- Keep the interfaces, but rename the Lucene* impls to Directory*.
Whatever we do, I'd like to make the impls/interfaces impl also TwoPhaseCommit.