Issue in Model design

[Naveen Kumar Idss]

Hi,
I am a starter when it comes to Java, I started with a ecommerce site but facing design issues. It is as follows :

1) I have created JPA entities for the tables in the database with mappings.
2) Created an interface called as service which has
Create(--) - adds data | Update(--) - updates data | Find(--),findal(--) - search data l delete(--) - deletes data
runQuery(--) - runs the query and returns the 'Query' (jpql)
executeQuery(--) - executes query (jpql)
3) Then created the service implementations for the tables accesing the entites created for tables.
4) After this I created Model where it does the CRUD operations with the services, using service interface.
5) The reason I did like this is I wanted the model to be portable to other ORM (Ex : Hibernate or other)
6) There are few cases where I need a method other than these like verifyAdmin(-) to verify administrator in administrator model;
7) I am able to write this method in the Administrator model, but the query results Objects, so I have to again import the entity, service into Administrator model. Which I do not want to do.
8) So it is clear that I cannot have a single interface Interface or abstract class for the services as each model may have different methods based on the requirement. ex : verifying user.
9) I feel following to be solutions :

a) Define interface for each of the service that corresponds to each entity.
b) Find a way that the Jpql gives a result set that I can type cast to string, int or float, without importing the service classes into model.

It would be a great help if any suggestions are provided, I am ready to re write the whole thing if the structure is wrong.

[Vijitha Kumara]

Some of your points are not clear to me, it might help if you can explain this with some pieces of sample code?

[Naveen Kumar Idss]

Sure,

Lets take one instance EX : administrator

table :
CREATE TABLE IF NOT EXISTS `ecom_admin` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `ecom_org_id` int(10) unsigned NOT NULL, `ecom_priority_prty_id` int(10) unsigned NOT NULL, `ecom_city_id` int(10) unsigned NOT NULL, `ecom_state_id` int(10) unsigned NOT NULL, `ecom_country_cntry_id` int(10) unsigned NOT NULL, `admin_user` varchar(150) NOT NULL, `admin_pass` varchar(250) NOT NULL, `admin_name` varchar(150) NOT NULL, `admin_email` varchar(250) NOT NULL, `admin_phoneone` varchar(15) NOT NULL, `admin_phonetwo` varchar(15) DEFAULT NULL, `admin_address` varchar(400) NOT NULL, `admin_zipcode` varchar(10) NOT NULL, PRIMARY KEY (`id`), KEY `ecom_admin_FKIndex1` (`ecom_country_cntry_id`), KEY `ecom_admin_FKIndex2` (`ecom_state_id`), KEY `ecom_admin_FKIndex3` (`ecom_city_id`), KEY `ecom_admin_FKIndex4` (`ecom_priority_prty_id`), KEY `ecom_admin_FKIndex5` (`ecom_org_id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=5 ;

Entity : in jpa_entity package

package jpa_entity ;

import java.io.Serializable;
import javax.persistence.*;
import javax.xml.bind.annotation.XmlRootElement;

/**
 *
 * @author Naveen
 */
@Entity
@Table(name = "ecom_admin")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "EcomAdmin.findAll", query = "SELECT e FROM EcomAdmin e")})
public class EcomAdmin implements Serializable {
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "id")
    private Integer id;
    @Basic(optional = false)
    @Column(name = "admin_name")
    private String adminName;
    @Basic(optional = false)
    @Column(name = "admin_user")
    private String adminUser;
    @Basic(optional = false)
    @Column(name = "admin_pass")
    private String adminPass;
    @Column(name="ecom_priority_prty_id", nullable=false,insertable=false, updatable=false)
    private int prtyID;
    @Embedded
    @AttributeOverrides({
        @AttributeOverride(name="address", column=@Column(name="admin_address",table="ecom_admin")),
        @AttributeOverride(name="email", column=@Column(name="admin_email", table="ecom_admin")),
        @AttributeOverride(name="phoneone", column=@Column(name="admin_phoneone", table="ecom_admin")),
        @AttributeOverride(name="phonetwo", column=@Column(name="admin_phonetwo", table="ecom_admin")),
        @AttributeOverride(name="zipcode",  column=@Column(name="admin_zipcode", table="ecom_admin"))
    })
    private Address address;
    @JoinColumn(name = "ecom_org_id", referencedColumnName = "id")
    @ManyToOne
    private EcomOrg ecomOrg;
    @JoinColumn(name = "ecom_priority_prty_id", referencedColumnName = "id")
    @ManyToOne
    private EcomPriorityPrty ecomPriorityPrty;
    @Embedded
    private CnStCi cnstci;
/-- setters and Getters --/

Service Interface in ServiceInterface package

package ServiceInterface;

import java.util.Collection;
import java.util.List;
import java.util.Map;

public interface DBService {
    public boolean create(Map<String,Object> m);
    public boolean update(Map<String,Object> m);
    public Object find(int id);
    public Collection findAll();
    public boolean delete(int id);
    public Collection runQuery(String query);
    public int executeQuery(String Query);
    public List<Object> setData(Map<String,Object> m,List<Object> l);
}

This is the Administrator service that implements interface

package DBService;

import ServiceInterface.DBService;
import jpa_entity.*;
import java.util.*;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;

public class SAdministrator implements DBService {
    private EntityManagerFactory emf;
    private EntityManager em;
    private EcomAdmin administrator;
    private Address address;
    private CnStCi cnstci;
    private EcomPriorityPrty priority;
    private List<Object> objects,retObjects;
    private enum fields {ID,PRIRTYID,ORGID,CITYID,STATEID,CNTRYID,USER,PASS,NAME,EMAIL,PONE,PTWO,ADDRS,ZIP};
   
    public SAdministrator()
    {
        emf=Persistence.createEntityManagerFactory("ecommercePU");
        em=emf.createEntityManager();
        objects=new ArrayList<Object>();
        retObjects=new ArrayList<Object>();
    }
   
    @Override
    public boolean create(Map<String, Object> m) {
        objects.add(new EcomAdmin());
        objects.add(new Address());
        objects.add(new CnStCi());
        retObjects.addAll(this.setData(alterFields(m,em), objects));
        administrator=(EcomAdmin)retObjects.get(0);
        address=(Address)retObjects.get(1);
        cnstci=(CnStCi)retObjects.get(2);
        administrator.setAddress(address);
        administrator.setCnstci(cnstci);
        em.getTransaction().begin();
        em.persist(administrator);
        em.getTransaction().commit();
        this.closeEntity();
        return true;
    }

    @Override
    public boolean update(Map<String, Object> m) {
        objects.add(em.find(EcomAdmin.class, m.get("ID")));
        objects.add(new Address());
        objects.add(new CnStCi());
        retObjects.addAll(this.setData(alterFields(m,em), objects));
        administrator=(EcomAdmin)retObjects.get(0);
        address=(Address)retObjects.get(1);
        cnstci=(CnStCi)retObjects.get(2);
        administrator.setAddress(address);
        administrator.setCnstci(cnstci);
        em.getTransaction().begin();
        em.persist(administrator);
        em.getTransaction().commit();
        this.closeEntity();
        return true;
    }

    @Override
    public EcomAdmin find(int id) {
        administrator=em.find(EcomAdmin.class, id);
        this.closeEntity();
        return administrator;
    }

    @Override
    public Collection findAll() {
        Query query=em.createNamedQuery("EcomAdmin.findAll");
        objects=query.getResultList();
        this.closeEntity();
        return objects;
    }

    @Override
    public boolean delete(int id) {
        administrator=em.find(EcomAdmin.class, id);
        em.getTransaction().begin();
        em.remove(administrator);
        em.getTransaction().commit();
        this.closeEntity();
        return true;
    }

    @Override
    public Collection runQuery(String queryString) {
        Query query=em.createQuery(queryString);
        objects=query.getResultList();
        this.closeEntity();
        return objects;
    }

    @Override
    public int executeQuery(String queryString) {
        Query query=em.createQuery(queryString);
        this.closeEntity();
        return query.executeUpdate();
    }
@Override
    public List<Object> setData(Map<String,Object> m,List<Object> l) {
        HashMap<String,Object> fieldMap=(HashMap)m;
        administrator=(EcomAdmin) l.get(0);
        address=(Address) l.get(1);
        cnstci=(CnStCi) l.get(2);
        for(String str:fieldMap.keySet())
        {
            switch(fields.valueOf(str))
            {
                case ID : administrator.setId((Integer)fieldMap.get(str)); break;
                case CNTRYID : cnstci.setEcomCountryCntry((EcomCountryCntry)fieldMap.get(str));break;
                case STATEID : cnstci.setEcomState((EcomState)fieldMap.get(str));break;
                case CITYID : cnstci.setEcomCity((EcomCity)fieldMap.get(str));break;
                case ORGID : administrator.setEcomOrg((EcomOrg)fieldMap.get(str));break;
                case PRIRTYID : administrator.setEcomPriorityPrty((EcomPriorityPrty)fieldMap.get(str));break;
                case USER : administrator.setAdminUser(fieldMap.get(str).toString());break;
                case PASS : administrator.setAdminPass(fieldMap.get(str).toString());break;
                case NAME : administrator.setAdminName(fieldMap.get(str).toString());break;
                case EMAIL : address.setEmail(fieldMap.get(str).toString());break;
                case PONE : address.setPhoneone(fieldMap.get(str).toString());break;
                case PTWO : address.setPhonetwo(fieldMap.get(str).toString());break;
                case ADDRS : address.setAddress(fieldMap.get(str).toString());break;
                case ZIP : address.setZipcode(fieldMap.get(str).toString());break;
            }
        }
        l.clear();
        l.add(administrator);
        l.add(address);
        l.add(cnstci);
        return l;
    }
    
    public void closeEntity()
    {
        em.close();
        emf.close();
    }
    
    public Map<String, Object> alterFields(Map<String, Object> m, EntityManager em)
    {
        m.put("CNTRYID", em.find(EcomCountryCntry.class, m.get("CNTRYID")));
        m.put("STATEID", em.find(EcomState.class, m.get("STATEID")));
        m.put("CITYID", em.find(EcomCity.class, m.get("CITYID")));
        m.put("ORGID", em.find(EcomOrg.class, m.get("ORGID")));
        m.put("PRIRTYID", em.find(EcomPriorityPrty.class, m.get("PRIRTYID")));
        return m;
    }
    public Query verifyAdmin(String user,String pass)
    {
        Query query=em.createQuery("SELECT a.adminName,p.prtyValue FROM EcomAdmin a,EcomPriorityPrty p 
                                                           WHERE a.adminUser='"+user+"' AND a.adminPass='"+pass+"' AND p.id=a.prtyID");
        return query;
    }
}

Model of Administrator

package Model;

import DBService.SAdministrator;
import ServiceInterface.DBService;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import javax.persistence.Query;

/**
 *
 * @author Naveen
 */
public class Administrator {
    private DBService dbService;
    public Administrator()
    {
      dbService=new SAdministrator();        
    }
    public boolean create(Map<String,Object> m)
    {
      return dbService.create(m);
    }
    public boolean update(Map<String,Object> m)
    {
      return dbService.update(m);
    }
    public Object find(int id)
    {
      return dbService.find(id);
    }
    public Collection findAll()
    {
      return dbService.findAll();
    }
    public boolean delete(int id)
    {
      return dbService.delete(id);
    }
    public Collection runQuery(String query)
    {
      return dbService.runQuery(query);
    }
    public int executeQuery(String query)
    {
        return dbService.executeQuery(query);
    }
    public String[] verifyAdmin(String user,String pass)
    {
        SAdministrator ad=new SAdministrator();
        Query query=ad.verifyAdmin(user, pass);
        String[] params= {query.getParameterValue("adminName").toString(),query.getParameter("prtyValue").toString()};
        return params;
    }    
}

now in verifyAdmin(String user,String pass) method I have to initiate SAdministrator, because it has a method that is not in interface, the further change I am thinking is to make an abstract class implementing the service
interface so I can implement

...
    @Override
    public Collection runQuery(String queryString) {
        Query query=em.createQuery(queryString);
        objects=query.getResultList();
        this.closeEntity();
        return objects;
    }

    @Override
    public int executeQuery(String queryString) {
        Query query=em.createQuery(queryString);
        this.closeEntity();
        return query.executeUpdate();
    }
...

which are common.

So, as we can see in the model I only want to have the interface or abstract imported....