public void insertRobotRules(LinkRelevance link, SimpleRobotRules robotRules) {
        if (link == null || robotRules == null) {
            throw new NullPointerException("Link argument or robot rules argument cannot be null");
        }
        frontierManager.getFrontier().insertRobotRules(link, robotRules);
    }
Inserts the robot rules object into the HashMap

@throws NullPointerException when either of the argument is null
ache/src/main/java/achecrawler/link/LinkStorage.java