Example usage for java.util.concurrent.atomic AtomicReference updateAndGet

Introduction

In this page you can find the example usage for java.util.concurrent.atomic AtomicReference updateAndGet.

Prototype

public final V updateAndGet(UnaryOperator<V> updateFunction) 

Source Link

Document

Atomically updates (with memory effects as specified by VarHandle#compareAndSet ) the current value with the results of applying the given function, returning the updated value.

Usage

From source file:org.workspace7.moviestore.controller.ShoppingCartController.java

/**
 * @param modelAndView/* ww w  .  j ava2s.  c om*/
 * @param session
 * @param response
 * @return
 */
@GetMapping("/cart/show")
public ModelAndView showCart(ModelAndView modelAndView, HttpSession session, HttpServletResponse response) {

    final String hostname = System.getenv().getOrDefault("HOSTNAME", "unknown");

    modelAndView.addObject("hostname", hostname);

    MovieCart movieCart = (MovieCart) session.getAttribute(SESSION_ATTR_MOVIE_CART);

    log.info("Showing Cart {}", movieCart);

    if (movieCart != null) {

        modelAndView.addObject("movieCart", movieCart);
        AtomicReference<Double> cartTotal = new AtomicReference<>(0.0);
        Map<String, Integer> movieItems = movieCart.getMovieItems();
        List<MovieCartItem> cartMovies = movieCart.getMovieItems().keySet().stream().map(movieId -> {
            Movie movie = movieDBHelper.query(movieId);
            int quantity = movieItems.get(movieId);
            double total = quantity * movie.getPrice();
            cartTotal.updateAndGet(aDouble -> aDouble + total);
            log.info("Movie:{} total for {} items is {}", movie, quantity, total);
            return MovieCartItem.builder().movie(movie).quantity(quantity).total(total).build();
        }).collect(Collectors.toList());
        modelAndView.addObject("cartItems", cartMovies);
        modelAndView.addObject("cartCount", cartMovies.size());
        modelAndView.addObject("cartTotal",
                "" + DecimalFormat.getCurrencyInstance(Locale.US).format(cartTotal.get()));
        modelAndView.setViewName("cart");

    } else {
        modelAndView.setViewName("redirect:/");
    }
    return modelAndView;
}

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