Get orders contains given product category

OrderResource.java

    @RequestMapping("")
    public List<Order> getOrdersByProductCategory (@RequestParam("category") final Optional<String> category) {
        return orderRepo.findAll().stream().
                filter(o -> o.getProducts().stream().anyMatch(p -> {
                    if (category.isEmpty()) {
                        return true;
                    }
                    return category.get().equalsIgnoreCase(p.getCategory());
                })).
                map(o -> new Order(o.getId(), o.getOrderDate(), o.getDeliveryDate(), o.getStatus())).
                collect(Collectors.toList());
    }