مولّد مخطط استدعاءات Java

class InvoiceService {
    int totalFor(String customer) {
        return sum(load(customer));
    }

    int[] load(String customer) {
        return new int[] { 1000, 2500, 400 };
    }

    int sum(int[] amounts) {
        int total = 0;
        for (int amount : amounts) {
            total += amount;
        }
        return total;
    }
}