public int compareTo(Object obj) {
        
        // If it is an arena, give it priority
        if (obj instanceof Arena)
            return 1;
        
        User u = (User) obj;
        
        String a = (this.isOnline()?"AAAA_":"BBBB_")+this.getUser();
        String b = (u.isOnline()?"AAAA_":"BBBB_")+u.getUser();
        return a.compareToIgnoreCase(b);
        
    }