@Override
public Index createIndex(FileSet fileset, RecordFactory recordFactory)
{
String fnDictionary = fileset.filename(Names.extHashExt) ;
PlainFile dictionary = FileFactory.createPlainFileDisk(fnDictionary) ;
String fnBuckets = fileset.filename(Names.extHashBucketExt) ;
BlockMgr mgr = createBlockMgr(fnBuckets, blockSize) ;
ExtHash eHash = new ExtHash(dictionary, recordFactory, mgr) ;
return eHash ;