Retrieving the index format

[Dan Climan <dc...@keepmedia.com>]

Is there a way to retrieve the tell which format an index is in?  The file formats documentation http://lucene.apache.org/java/docs/fileformats.html#Segments%20File indicates that the segments file stores a Format value that can be used to determine the type.

 Format is -1 as of Lucene 1.4 and -3 (SemgentInfos.FORMAT_SINGLE_NORM_FILE) as of Lucene 2.1.

However, there doesn't seem to be an API to retrieve this value. Is it not exposed because it is intended only for internal code to maintain backward compatibility?  Since I have a mix of old and new indices in test environments, I thought