private String deletePizza(Pizzeria pizzeria, Pizza pizza, PizzeriaPizzaForm form) {
    List<RelationPizzeriaPizza> pizzeriaPizzas = pizzeria.getPizzasPriceList();

    /*
     * Only update the pizza if the pizzeria has already a
     * RelationPizzeriaPizza with the same id.
     */
    for (RelationPizzeriaPizza pizzeriaPizza : pizzeriaPizzas) {
      if (pizzeriaPizza.getId() == form.getId()) {

        /*
         * FIXME - Prevent the elimination of RelationPizzeriaPizzas
         * which belong to an OrderItem which has not yet been
         * collected.
         */

        RelationPizzeriaPizzaDAO dao =
            (RelationPizzeriaPizzaDAO) context.getBean("relationPizzeriaPizzaDAO");
        pizzeriaPizza.setAvailable(false);
        dao.update(pizzeriaPizza);
        return buildOkResponse(pizzeriaPizza);
      }
    }

    return buildErrorResponse();
  }
  private String updatePizza(Pizzeria pizzeria, Pizza pizza, PizzeriaPizzaForm form) {
    List<RelationPizzeriaPizza> pizzeriaPizzas = pizzeria.getPizzasPriceList();

    /*
     * Only update the pizza if the pizzeria has already a
     * RelationPizzeriaPizza with the same id.
     */
    for (RelationPizzeriaPizza pizzeriaPizza : pizzeriaPizzas) {
      if (pizzeriaPizza.getId() == form.getId()) {
        pizzeriaPizza.setPizza(pizza);
        pizzeriaPizza.setPizzaSize(form.getSize());
        pizzeriaPizza.setPreparationTime(form.getPreparationTimeInSeconds());
        pizzeriaPizza.setGlutenFree(form.getGlutenFree());
        pizzeriaPizza.setPrice(form.getPrice());

        RelationPizzeriaPizzaDAO dao =
            (RelationPizzeriaPizzaDAO) context.getBean("relationPizzeriaPizzaDAO");
        dao.update(pizzeriaPizza);

        return buildOkResponse(pizzeriaPizza);
      }
    }

    return buildErrorResponse();
  }
  private String addPizza(Pizzeria pizzeria, Pizza pizza, PizzeriaPizzaForm form) {
    RelationPizzeriaPizza pizzeriaPizza =
        new RelationPizzeriaPizza(
            pizzeria,
            pizza,
            form.getPrice(),
            form.getSize(),
            form.getPreparationTimeInSeconds(),
            form.getGlutenFree());

    // FIXME - Validate data: user can't add an entry that already exists
    // (same data).

    RelationPizzeriaPizzaDAO dao =
        (RelationPizzeriaPizzaDAO) context.getBean("relationPizzeriaPizzaDAO");

    dao.create(pizzeriaPizza);

    /*
     * Now the pizzeriaPizza object contains the id of the newly created
     * instance.
     */
    return buildOkResponse(pizzeriaPizza);
  }