How to remove part of a hashmap value?

Question

So I'm building a group of dropdowns that rely upon each other and built a query to get the code and description for a Product Type, Family, and Model object. I used nested hashmaps to story all of the data and objects. This was fine because I can just call all of the information that I need from the hashmaps. However, when it comes to the REST API's, it's going to display all of the nested information for each of the hashmaps when I call them. For each map I have it's key, and then the value consists of a Code, Desc, and the hashmap of the next object.

So, it would be like:

Main hashmap
 - Key
 - value
    -> code
    -> desc
    -> product family hashmap
       -- key
       -- value
          --> code
          --> desc
          --> product model hashmap
              --- key
              --- value
                  ---> code
                  ---> desc  

My main question is how can I either strip these additional hashmaps from being displayed in the json format when viewing the REST API via web browser? Or can/do I need to just completely strip the additional information altogether?

@Service
public class ProductDAOImpl implements ProductDAO {
    @PersistenceContext
    private EntityManager em;

    @Override
    public Map<String, ProductType> getProductTypeStructure() {
        HashMap<String, ProductType> prodTypes = new HashMap<>();
        Query q = em.createNativeQuery("<query>");


        List<Object[]> prodTypeEntities = q.getResultList();
        final String badData = "XX-BAD-XX";
        ProductType prodType = new ProductType(badData, "");
        ProductFamily prodFamily = new ProductFamily(badData, "");


        for(Object[] prodTypeEntity : prodTypeEntities) {


            if (prodTypeEntity[1] == null || prodTypeEntity[3] == null || prodTypeEntity[5] == null) {
                continue;
            }

            String prodTypeCd = prodTypeEntity[0].toString().toUpperCase();
            String prodTypeDesc = StringUtils.trimTrailingWhitespace(prodTypeEntity[1].toString()).toUpperCase(); 

            String prodFamilyCd = prodTypeEntity[2].toString().toUpperCase();
            String prodFamilyDesc = StringUtils.trimTrailingWhitespace(prodTypeEntity[3].toString()).toUpperCase(); 

            String prodModelCd = prodTypeEntity[4].toString().toUpperCase();
            String prodModelDesc = StringUtils.trimTrailingWhitespace(prodTypeEntity[5].toString()).toUpperCase(); 

            if(!prodType.getCode().equalsIgnoreCase(prodTypeCd)) {   
                prodType = new ProductType(prodTypeCd, prodTypeDesc); 
                prodType.setProdFamilies(new HashMap<String, ProductFamily>());
                prodTypes.put(prodType.getCode(), prodType);

                prodFamily.setCode(badData);
            }

            if(!prodFamily.getCode().equalsIgnoreCase(prodFamilyCd)) {
                prodFamily = new ProductFamily(prodFamilyCd, prodFamilyDesc);
                prodFamily.setProdModels(new HashMap<String, ProductModel>());
                prodType.getProdFamilies().put(prodFamily.getCode(), prodFamily);
            }
            prodFamily.getProdModels().put(prodModelCd, new ProductModel(prodModelCd, prodModelDesc));

        }    
        return prodTypes;
    }

}

Answer 1

If I understood your question correctly, I think a DTO object might be the answer here. You add to it only the values that the dropdown might need and return it from the REST API.

Here's more on DTOs.