listCommits

Returns all commit points that exist in the Directory. Normally, because the default is [ ], there would be only one commit point. But if you're using a custom IndexDeletionPolicy then there could be many commits. Once you have a given commit, you can open a reader on it by calling DirectoryReader.open There must be at least one commit in the Directory, else this method throws [ ]. Note that if a commit is in progress while this method is running, that commit may or may not be returned.