Java API code with Spring

Question

Model:

public class UserBean { 
 @JsonProperty
 private String userId; 
 @JsonProperty
 private int limit; 
 @JsonProperty
 private int page;
 public String getUserId() {
 return userId;
 }
 public void setUserId(String userId) {
 this.userId = userId;
 }
 public int getLimit() {
 return limit;
 }
 public void setLimit(int limit) {
 this.limit = limit;
 }
 public int getPage() {
 return page;
 }
 public void setPage(int page) {
 this.page = page;
 }
}
public class ResponseJSON {
 private Map<String, Object> response = new LinkedHashMap<String, Object>(); 
 public void setStatus(String status) {
 response.put("status", status);
 }
 public void setMessage(String message) {
 response.put("message", message);
 } 
 public void add(String key, Object value) {
 response.put(key, value);
 } 
 public Map<String, Object> get() {
 return this.response;
 }
}

Controller:

@ResponseBody
@RequestMapping(value = "/user/products", method = RequestMethod.POST)
public Object getProductListByUser(@RequestBody UserBean userBean) {
 ResponseJSON responseJSON = new ResponseJSON();
 try {
 List<Object> result = userRepository.getProductListByUser(userBean);
 int resultCount = result.size();
 List<Object> productList = new ArrayList<Object>();
 for (int i = 0; i < resultCount; i++) {
 ProductInfo product = (ProductInfo) result.get(i);
 Map<String, Object> productInfo = new LinkedHashMap<String, Object>(); 
 productInfo.put("id", product.getId());
 productInfo.put("title", product.getTitle());
 productInfo.put("description", product.getDescription());
 productInfo.put("iconImage", product.getIconImage()); 
 productInfo.put("updateDatetime", product.getUpdateDatetime());
 productInfo.put("createDatetime", product.getCreateDatetime());
 productList.add(productInfo);
 }
 responseJSON.setStatus(Constants.SUCCESS);
 responseJSON.add("items", productList); 
 } catch (Exception e) {
 responseJSON.setStatus(Constants.FAIL);
 responseJSON.setMessage(e.getMessage());
 logger.error(e.getMessage());
 }
 return responseJSON.get();
}

Repository:

@SuppressWarnings("unchecked")
@Transactional
public List<Object> getProductListByUser(UserBean userBean) {
 Session session = sessionFactory.getCurrentSession();
 Criteria criteria = session.createCriteria(ProductInfo.class, "product")
 .createAlias("product.productOptions", "options", CriteriaSpecification.LEFT_JOIN)
 .add(Restrictions.eq("product.userId", userBean.getUserId()))
 .addOrder(Order.asc("productOptions.size"))
 .setFirstResult((userBean.getPage() - 1) * userBean.getLimit());
 .setMaxResults(userBean.getLimit());
 return criteria.list(); 
}

I'm developing some back-end APIs. This API returns product lists of some user. Purpose of this API is returning result of JSON data. So, I get datas from repository and assign to ResponseJSON object in the controller. Is this approach efficient or not? Which way is better?

Answer 1

It would be easier to follow the getProductListByUser method if you use two ResponseJSON instance. One for normal execution and one for the exceptional cases:

try {
 ...
 final ResponseJSON responseJSON = new ResponseJSON();
 ...
 responseJSON.setStatus(Constants.SUCCESS);
 responseJSON.add("items", productList); 
 return responseJSON.get();
} catch (final Exception e) {
 final ResponseJSON responseJSON = new ResponseJSON();
 responseJSON.setStatus(Constants.FAIL);
 responseJSON.setMessage(e.getMessage());
 logger.error(e.getMessage());
 return responseJSON.get();
}

It also ensures that nobody modifies accidentally the exception case result in the try block and there isn't any incomplete ProductInfo data in the error response.