DataTable Row Group

@Named("dtRowGroupView")
@ViewScoped
public class RowGroupView implements Serializable {

    private List<Customer> customers;

    @Inject
    private CustomerService service;

    @PostConstruct
    public void init() {
        customers = service.getCustomers(50);
    }

    public long getTotalCount(String name) {
        return customers.stream().filter(customer -> name.equals(customer.getRepresentative().getName())).count();
    }

    public List<Customer> getCustomers() {
        return customers;
    }

    public void setService(CustomerService service) {
        this.service = service;
    }
}

@Named
@ApplicationScoped
public class CustomerService {

    private Random random = new SecureRandom();
    private Country[] countries;
    private Representative[] representatives;
    private String[] firstNames;
    private String[] lastNames;
    private String[] companies;

    @PostConstruct
    public void init() {
        countries = new Country[]{
            new Country(0, "Argentina", "ar"),
            new Country(1, "Australia", "au"),
            new Country(2, "Brazil", "br"),
            new Country(3, "Canada", "ca"),
            new Country(4, "Germany", "de"),
            new Country(5, "France", "fr"),
            new Country(6, "India", "in"),
            new Country(7, "Italy", "it"),
            new Country(8, "Japan", "jp"),
            new Country(9, "Russia", "ru"),
            new Country(10, "Spain", "es"),
            new Country(11, "United Kingdom", "gb")};

        companies = new String[]{"Benton, John B Jr", "Chanay, Jeffrey A Esq", "Chemel, James L Cpa", "Feltz Printing Service",
            "Printing Dimensions", "Chapman, Ross E Esq", "Morlong Associates", "Commercial Press", "Truhlar And Truhlar Attys",
            "King, Christopher A Esq", "Dorl, James J Esq", "Rangoni Of Florence", "Feiner Bros", "Buckley Miller Wright",
            "Rousseaux, Michael Esq"};

        representatives = new Representative[]{
            new Representative("Amy Elsner", "amyelsner.png"),
            new Representative("Anna Fali", "annafali.png"),
            new Representative("Asiya Javayant", "asiyajavayant.png"),
            new Representative("Bernardo Dominic", "bernardodominic.png"),
            new Representative("Elwin Sharvill", "elwinsharvill.png"),
            new Representative("Ioni Bowcher", "ionibowcher.png"),
            new Representative("Ivan Magalhaes", "ivanmagalhaes.png"),
            new Representative("Onyama Limba", "onyamalimba.png"),
            new Representative("Stephen Shaw", "stephenshaw.png"),
            new Representative("Xuxue Feng", "xuxuefeng.png")};

        firstNames = new String[]{"James", "David", "Jeanfrancois", "Ivar", "Tony",
            "Adams", "Claire", "Costa", "Juan", "Maria", "Jennifer",
            "Stacey", "Leja", "Morrow", "Arvin", "Darci", "Izzy",
            "Ricardo", "Clifford", "Emily", "Kadeem", "Mujtaba", "Aika",
            "Mayumi", "Misaki", "Silvio", "Nicolas", "Antonio",
            "Deepesh", "Aditya", "Aruna", "Jones", "Julie", "Smith",
            "Johnson", "Francesco", "Salvatore", "Kaitlin", "Faith",
            "Maisha", "Jefferson", "Leon", "Rodrigues", "Alejandro",
            "Munro", "Cody", "Chavez", "Sinclair", "Isabel", "Octavia",
            "Murillo", "Greenwood", "Wickens", "Ashley"};
        lastNames = new String[]{"Butt", "Darakjy", "Venere", "Paprocki", "Foller",
            "Morasca", "Tollner", "Dilliard", "Wieser", "Marrier", "Amigon",
            "Maclead", "Caldarera", "Ruta", "Albares", "Poquette", "Garufi",
            "Gaucho", "Rim", "Whobrey", "Flosi", "Nicka", "Inouye",
            "Kolmetz", "Royster", "Slusarski", "Iturbide", "Caudy",
            "Chui", "Kusko", "Figeroa", "Vocelka", "Stenseth", "Glick",
            "Sergi", "Shinko", "Stockham", "Ostrosky", "Gillian",
            "Rulapaugh", "Schemmer", "Oldroyd", "Campain", "Perin",
            "Ferencz", "Saylors", "Briddick", "Waycott", "Bowley", "Malet",
            "Malet", "Bolognia", "Nestle", "Doe"};
    }

    public List<Customer> getCustomers(int number) {
        List<Customer> customers = new ArrayList<>();
        for (int i = 0; i < number; i++) {
            customers.add(
                    new Customer(i + 1000, getName(), getCompany(), getCountry(), getDate(),
                            CustomerStatus.random(), getActivity(), getRepresentative()));
        }
        return customers;
    }

    public List<Country> getCountries() {
        return Arrays.asList(countries);
    }

    public CustomerStatus[] getCustomerStatus() {
        return CustomerStatus.values();
    }

    public List<Representative> getRepresentatives() {
        return Arrays.asList(representatives);
    }

    private String getName() {
        return firstNames[random.nextInt(firstNames.length)] + Constants.SPACE
                + (char) (random.nextInt(26) + 'A') + Constants.SPACE
                + lastNames[random.nextInt(lastNames.length)];
    }

    private Country getCountry() {
        return countries[random.nextInt(countries.length)];
    }

    private String getCompany() {
        return companies[random.nextInt(companies.length)];
    }

    private LocalDate getDate() {
        LocalDate now = LocalDate.now();
        long randomDay = ThreadLocalRandom.current().nextLong(now.minusDays(30).toEpochDay(), now.toEpochDay());
        return LocalDate.ofEpochDay(randomDay);
    }

    private int getActivity() {
        return random.nextInt(100);
    }

    private Representative getRepresentative() {
        return representatives[random.nextInt(representatives.length)];
    }
}