public List<Product> getProductList(
     ProductCategory productCategory, int firstResult, int maxResults) {
   return productDao.getProductList(productCategory, firstResult, maxResults);
 }
 public List<Product> getProductList(ProductCategory productCategory) {
   return productDao.getProductList(productCategory);
 }
 public List<Product> getProductList(int firstResult, int maxResults) {
   return productDao.getProductList(firstResult, maxResults);
 }
 public List<Product> getProductList(
     Date beginDate, Date endDate, int firstResult, int maxResults) {
   return productDao.getProductList(beginDate, endDate, firstResult, maxResults);
 }