public void select(RoutingContext ctx) {
        Hop hop = getRecipient(ctx);
        if (hop != null) {
            Route route = new Route(ctx.getRoute());
            route.setHop(0, hop);
            ctx.addChild(route);
        } else {
            Reply reply = new EmptyReply();
            reply.addError(new Error(ErrorCode.NO_ADDRESS_FOR_SERVICE,
                                     "None of the configured recipients are currently available."));
            ctx.setReply(reply);
        }
    }
This policy implements round-robin selection of the configured recipients that are currently registered in slobrok.

@author Simon Thoresen Hult
documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/RoundRobinPolicy.java