public void save(Category category) {
   if (category.getId() == null) {
     entityManager.persist(category);
   } else {
     entityManager.merge(category);
   }
   result.redirectTo(CategoryController.class).search();
 }
 public void delete(Category category) {
   entityManager.remove(entityManager.find(Category.class, category.getId()));
   result.redirectTo(CategoryController.class).search();
 }
 @Path("/category/edit/{category.id}")
 @Get
 public void edit(Category category) {
   result.include("category", entityManager.find(Category.class, category.getId()));
 }