class SimpleKeyValueLookupService extends AbstractControllerService implements StringLookupService {

    @Override
    public Optional<String> lookup(final Map<String, Object> coordinates) {
        if (coordinates == null) {
            return Optional.empty();
        }

        final String key = coordinates.get(KEY).toString();
        if (key == null) {
            return Optional.empty();
        }

        return Optional.ofNullable(lookupValues.get(key));
    }

}