Lucene .NET fixed filenames in index directory possible?

When building a Lucene .NET index it creates several randomly named files under the root index directory. My question 开发者_StackOverflow中文版is, is there a way to have these files have a static or fixed name and just overwrite upon re-index, or all be in one file?

If you use cfs, there will be just one file (random stuff.cfs)