public Set<String> files(){
  if (setFiles == null) {
    throw new IllegalStateException("files were not computed yet");
  }
  return Collections.unmodifiableSet(setFiles);
}

public Set < String > files ( ) { if ( setFiles == null ) { throw new IllegalStateException ( "files were not computed yet" ) ; } return Collections . unmodifiableSet ( setFiles ) ; }
return all files referenced by this segmentinfo .
