import java.util.*; public class PaymentPresenter { public String toString(Payment[] payments) { Arrays.sort(payments); StringBuilder string = new StringBuilder(); for (Payment o : payments) { string.append(o.getShortDescription() + "\n"); } return string.toString(); } public String toStringByPayerName(Payment[] payments) { Arrays.sort(payments, new paymentSortByPayer()); StringBuilder string = new StringBuilder(); for (Payment o : payments) { o.getPayerName(); string.append(o.getShortDescription() + "\n"); } return string.toString(); } public String toStringById(Payment[] payments) { Arrays.sort(payments, (Payment a, Payment b) -> Long.compare(a.getId(), b.getId())); StringBuilder string = new StringBuilder(); for (Payment o : payments) { string.append(o.getShortDescription() + "\n"); } return string.toString(); } }