question: public void writeToSdfDir ( File sdfDir ) throws IOException { if ( ReaderUtils . isSDF ( sdfDir ) ) { writeToFile ( new File ( sdfDir , ReferenceGenome . REFERENCE_FILE ) ) ; } else { throw new IOException ( String . format ( "%s is not an SDF" , sdfDir . getPath ( ) ) ) ; } }
target:  install this reference.txt into an SDF