@Override
 public void addProduct(Product product) {
   productRepository.addProduct(product);
 }
 @Override
 public Product getProductById(String productId) {
   return productRepository.getProductById(productId);
 }
 @Override
 public List<Product> getProductsByCategory(String category) {
   return productRepository.getProductsByCategory(category);
 }
 @Override
 public Set<Product> getProductsByFilter(Map<String, List<String>> filterParams) {
   return productRepository.getProductsByFilter(filterParams);
 }
 @Override
 public List<Product> getAllProducts() {
   return productRepository.getAllProducts();
 }