[netcdf-java] Netcdf Java Index Files

It appears that opening different file types can generate index files, most notably GRIB with the .gbx9 index files. Is there an API call by which I might detect whether an index file will be created when the file is opened, like NetcdfFile.createsIndexFile( "/tmp/myfile.xyz")? I'm assuming there is not, but thought I'd ask...

Thanks,
Aaron