public Optional<Server> chooseRoundRobinAfterFiltering(List<Server> servers, Object loadBalancerKey) {
        List<Server> eligible = getEligibleServers(servers, loadBalancerKey);
        if (eligible.size() == 0) {
            return Optional.absent();
        }
        return Optional.of(eligible.get(incrementAndGetModulo(eligible.size())));
    }
Choose a server in a round robin fashion after the predicate filters a given list of servers and load balancer key.
ribbon-loadbalancer/src/main/java/com/netflix/loadbalancer/AbstractServerPredicate.java