public void restoreState(Map<String, Optional<?>> state) { Optional.ofNullable(state.get(EVICTION_STATE_KEY)) .flatMap(x -> x) .ifPresent(v -> ((EvictionPolicy) evictionPolicy).restoreState(v)); Optional.ofNullable(state.get(TRIGGER_STATE_KEY)) .flatMap(x -> x) .ifPresent(v -> ((TriggerPolicy) triggerPolicy).restoreState(v)); }