Task with java methods invoiceService

can you help me on this tasks? Elaborate classified publishing invoice functionality. When exploiting invoices, you can have two ranges: submitting an invoice can be removed by email to the client or to the client invoice, permission to protect web sites for printing spaces to print for printing. The invoice classification code is the basis:

public class InvoiceService {
private PrinterService printerService = null;
private EmailService emailService = null;
public InvoiceService(PrinterService printerService, EmailService
emailService) {
this.printerService = printerService;
this.emailService = emailService;
}
public void handleInvoice(Invoice invoice, Customer customer) {
if (customer.prefersEmails()) {
emailService.sendInvoice(invoice, customer.getEmail());
} else {
printerService.printInvoice(invoice);
}
}
}