package org.jpwh.model.inheritance.associations.onetomany;

 import org.jpwh.model.Constants;

 import javax.persistence.*;

 import javax.validation.constraints.NotNull;

 // Can not be @MappedSuperclass when it's a target class in associations!

 @Entity

 @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)

 public abstract class BillingDetails {

     @Id

     @GeneratedValue(generator = Constants.ID_GENERATOR)

     protected Long id;

     @ManyToOne(fetch = FetchType.LAZY)

     protected User user;

     @NotNull

     protected String owner;

     protected BillingDetails() {

     }

     protected BillingDetails(String owner) {

         this.owner = owner;

     }

     public Long getId() {

         return id;

     }

     public String getOwner() {

         return owner;

     }

     public void setOwner(String owner) {

         this.owner = owner;

     }

     public User getUser() {

         return user;

     }

     public void setUser(User user) {

         this.user = user;

     }

     public void pay(int amount) {

         // NOOP

     }

     // ...

 }

 package org.jpwh.model.inheritance.associations.onetomany;

 import javax.persistence.Entity;

 import javax.validation.constraints.NotNull;

 @Entity

 public class BankAccount extends BillingDetails {

     @NotNull

     protected String account;

     @NotNull

     protected String bankname;

     @NotNull

     protected String swift;

     public BankAccount() {

         super();

     }

     public BankAccount(String owner, String account, String bankname, String swift) {

         super(owner);

         this.account = account;

         this.bankname = bankname;

         this.swift = swift;

     }

     public String getAccount() {

         return account;

     }

     public void setAccount(String account) {

         this.account = account;

     }

     public String getBankname() {

         return bankname;

     }

     public void setBankname(String bankname) {

         this.bankname = bankname;

     }

     public String getSwift() {

         return swift;

     }

     public void setSwift(String swift) {

         this.swift = swift;

     }

 }

 package org.jpwh.model.inheritance.associations.onetomany;

 import javax.persistence.Entity;

 import javax.validation.constraints.NotNull;

 @Entity

 public class CreditCard extends BillingDetails {

     @NotNull

     protected String cardNumber;

     @NotNull

     protected String expMonth;

     @NotNull

     protected String expYear;

     public CreditCard() {

         super();

     }

     public CreditCard(String owner, String cardNumber, String expMonth, String expYear) {

         super(owner);

         this.cardNumber = cardNumber;

         this.expMonth = expMonth;

         this.expYear = expYear;

     }

     public String getCardNumber() {

         return cardNumber;

     }

     public void setCardNumber(String cardNumber) {

         this.cardNumber = cardNumber;

     }

     public String getExpMonth() {

         return expMonth;

     }

     public void setExpMonth(String expMonth) {

         this.expMonth = expMonth;

     }

     public String getExpYear() {

         return expYear;

     }

     public void setExpYear(String expYear) {

         this.expYear = expYear;

     }

 }

 package org.jpwh.model.inheritance.associations.onetomany;

 import org.jpwh.model.Constants;

 import javax.persistence.*;

 import javax.validation.constraints.NotNull;

 import java.util.HashSet;

 import java.util.Set;

 @Entity

 @Table(name = "USERS")

 public class User {

     @Id

     @GeneratedValue(generator = Constants.ID_GENERATOR)

     protected Long id;

     @NotNull

     protected String username;

     @OneToMany(mappedBy = "user")

     protected Set<BillingDetails> billingDetails = new HashSet<>();

     public User() {

     }

     public User(String username) {

         this.username = username;

     }

     public Long getId() {

         return id;

     }

     public String getUsername() {

         return username;

     }

     public void setUsername(String username) {

         this.username = username;

     }

     public Set<BillingDetails> getBillingDetails() {

         return billingDetails;

     }

     public void setBillingDetails(Set<BillingDetails> billingDetails) {

         this.billingDetails = billingDetails;

     }

     // ...

 }

 package org.jpwh.test.inheritance;

 import org.jpwh.env.JPATest;

 import org.jpwh.model.inheritance.associations.onetomany.BankAccount;

 import org.jpwh.model.inheritance.associations.onetomany.BillingDetails;

 import org.jpwh.model.inheritance.associations.onetomany.CreditCard;

 import org.jpwh.model.inheritance.associations.onetomany.User;

 import org.testng.annotations.BeforeClass;

 import org.testng.annotations.Test;

 import javax.persistence.EntityManager;

 import javax.transaction.UserTransaction;

 import static org.testng.Assert.assertEquals;

 public class PolymorphicOneToMany extends JPATest {

     @Override

     public void configurePersistenceUnit() throws Exception {

         configurePersistenceUnit("PolymorphicOneToManyPU");

     }

     @Test

     public void storeAndLoadItemBids() throws Exception {

         UserTransaction tx = TM.getUserTransaction();

         try {

             tx.begin();

             EntityManager em = JPA.createEntityManager();

             BankAccount ba = new BankAccount(

                 "Jane Roe", "445566", "One Percent Bank Inc.", "999"

             );

             CreditCard cc = new CreditCard(

                 "John Doe", "1234123412341234", "06", "2015"

             );

             User johndoe = new User("johndoe");

             johndoe.getBillingDetails().add(ba);

             ba.setUser(johndoe);

             johndoe.getBillingDetails().add(cc);

             cc.setUser(johndoe);

             em.persist(ba);

             em.persist(cc);

             em.persist(johndoe);

             tx.commit();

             em.close();

             Long USER_ID = johndoe.getId();

             tx.begin();

             em = JPA.createEntityManager();

             {

                 User user = em.find(User.class, USER_ID);

                 for (BillingDetails billingDetails : user.getBillingDetails()) {

                     billingDetails.pay(123);

                 }

                 assertEquals(user.getBillingDetails().size(), 2);

             }

             tx.commit();

             em.close();

         } finally {

             TM.rollback();

         }

     }

 }