InvoiceAfter.java

public class Invoice {
    private final ShippingPricer shippingPricer;
    // ...

    public Invoice(
        OurDate billingDate,
        OurDate openingDate,
        Originator originator
        // ...
    ) {
        // ...
        this.shippingPricer = new ShippingPricer(billingDate, openingDate, originator);
    }

    // ...

    public Money getValue() {
        Money total = this.itemsSum();
        total.add(this.shippingPricer.getPrice());
        total.add(this.getTax());
        return total;
    }

    private Money itemsSum() {
        throw new RuntimeException("Not implemented");
    }

    // ...
}