Slide 38
Slide 38 text
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void addToOrder(Order order, Product product, Quantity quantity) {
Optional item = order.items.stream()
.filter(it -> it.product.equals(product));
// Update existing item or create new one
if (item.isPresent()) {
item.ifPresent(it -> it.increase(quantity));
} else {
order.items.add(new LineItem(product, quantity);
}
}