/** * Get the deferred flag. Exchange rates can be deferred or real.time. * * @return the deferred flag, or {code null}. */ public Set<RateType> getRateTypes() { @SuppressWarnings("unchecked") Set<RateType> rateSet = get(KEY_RATE_TYPES, Set.class); if (rateSet == null) { return Collections.emptySet(); } return Collections.unmodifiableSet(rateSet); }