package no.hvl.dat250.jpa.tutorial.relationshipexample; import jakarta.persistence.Entity; import jakarta.persistence.GeneratedValue; import jakarta.persistence.GenerationType; import jakarta.persistence.Id; import jakarta.persistence.OneToMany; import java.util.ArrayList; import java.util.List; import lombok.Getter; import lombok.NoArgsConstructor; import lombok.Setter; @Getter @Setter @NoArgsConstructor @Entity public class Family { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; private String description; @OneToMany(mappedBy = "family") private final List<Person> members = new ArrayList<>(); }

package no.hvl.dat250.jpa.tutorial.relationshipexample; import jakarta.persistence.Entity; import jakarta.persistence.GeneratedValue; import jakarta.persistence.GenerationType; import jakarta.persistence.Id; import lombok.Getter; import lombok.NoArgsConstructor; import lombok.Setter; @Entity @Getter @Setter @NoArgsConstructor public class Job { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; private double salary; private String jobDescr; }

package no.hvl.dat250.jpa.tutorial.relationshipexample; import jakarta.persistence.Entity; import jakarta.persistence.GeneratedValue; import jakarta.persistence.GenerationType; import jakarta.persistence.Id; import jakarta.persistence.ManyToOne; import jakarta.persistence.OneToMany; import jakarta.persistence.Transient; import java.util.ArrayList; import java.util.List; import lombok.Getter; import lombok.NoArgsConstructor; import lombok.Setter; @Getter @Setter @NoArgsConstructor @Entity public class Person { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; private String firstName; private String lastName; @ManyToOne private Family family; @Transient private String nonsenseField = ""; @OneToMany private List<Job> jobList = new ArrayList<>(); }

package no.hvl.dat250.jpa.tutorial.relationshipexample; import static org.junit.Assert.assertEquals; import jakarta.persistence.EntityManager; import jakarta.persistence.EntityManagerFactory; import jakarta.persistence.Persistence; import jakarta.persistence.Query; import org.junit.Before; import org.junit.Test; public class JpaTest { private static final String PERSISTENCE_UNIT_NAME = "jpa-tutorial"; private EntityManagerFactory factory; @Before public void setUp() { factory = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME); EntityManager em = factory.createEntityManager(); // Begin a new local transaction so that we can persist a new entity em.getTransaction().begin(); // read the existing entries Query q = em.createQuery("select m from Person m"); // Persons should be empty // do we have entries? boolean createNewEntries = (q.getResultList().size() == 0); // No, so lets create new entries if (createNewEntries) { assertEquals(0, q.getResultList().size()); Family family = new Family(); family.setDescription("Family for the Knopfs"); em.persist(family); for (int i = 0; i < 40; i++) { Person person = new Person(); person.setFirstName("Jim_" + i); person.setLastName("Knopf_" + i); person.setFamily(family); // now persists the family person relationship family.getMembers().add(person); em.persist(person); em.persist(family); } } // Commit the transaction, which will cause the entity to // be stored in the database em.getTransaction().commit(); // It is always good practice to close the EntityManager so that // resources are conserved. em.close(); } @Test public void checkAvailablePeople() { // now lets check the database and see if the created entries are there // create a fresh, new EntityManager EntityManager em = factory.createEntityManager(); // Perform a simple query for all the Message entities Query q = em.createQuery("select m from Person m"); // We should have 40 Persons in the database assertEquals(40, q.getResultList().size()); em.close(); } @Test public void checkFamily() { EntityManager em = factory.createEntityManager(); // Go through each of the entities and print out each of their // messages, as well as the date on which it was created Query q = em.createQuery("select f from Family f"); // We should have one family with 40 persons assertEquals(1, q.getResultList().size()); assertEquals(40, ((Family) q.getSingleResult()).getMembers().size()); em.close(); } @Test(expected = jakarta.persistence.NoResultException.class) public void deletePerson() { EntityManager em = factory.createEntityManager(); // Begin a new local transaction so that we can persist a new entity em.getTransaction().begin(); Query q = em .createQuery("SELECT p FROM Person p WHERE p.firstName = :firstName AND p.lastName = :lastName"); q.setParameter("firstName", "Jim_1"); q.setParameter("lastName", "Knopf_!"); Person user = (Person) q.getSingleResult(); em.remove(user); em.getTransaction().commit(); Person person = (Person) q.getSingleResult(); em.close(); } }