code: public static <T> T findValue(ServiceRegistry registry, ServiceName name) {
          ServiceController<T> service = findService(registry, name);
          return ((service != null) && (service.getState() == State.UP)) ? service.getValue() : null;
      }
docs: Returns the value of the specified service, if the service exists and is started.
  @param registry the service registry
  @param name the service name
  @return the service value, if the service exists and is started, null otherwise