em.find で見つかったエンティティは em で自動的に管理されていると思っていたのですが、以下のクラスはその逆のようです。私は間違っていましたか、それともそのクラスの間違いは何ですか?
@Stateful
@TransactionAttribute(NOT_SUPPORTED)
public class CustomerGateway {
@PersistenceContext(unitName = "customersPU", type = EXTENDED)
private EntityManager em;
private Customer customer;
public Customer find(Long id) {
// customer is not managed!
this.customer = em.find(Customer.class, id);
// Print false!
System.out.println("Method find: " + em.contains(customer));
// Print false too (2 is the id of an entity)!
System.out.println("Method find: " + em.contains(em.find(Customer.class, 2L));
// A workaround
customer = em.merge(customer);
// Print true.
System.out.println("Method find after merge: " + em.contains(customer));
return this.customer;
}
編集 1: エンティティのコード
@Entity
@NamedQuery(name = "Customer.all", query = "select c from Customer c")
public class Customer implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String name;
public Customer() {
}
public Customer(String name) {
this.name = name;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof Customer)) {
return false;
}
Customer other = (Customer) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
@Override
public String toString() {
return "entity.Customer[ id=" + id + " ]";
}
}
ステートフル EJB のコード:
@Stateful
@TransactionAttribute(NOT_SUPPORTED)
public class CustomerGateway {
@PersistenceContext(type = PersistenceContextType.EXTENDED)
private EntityManager em;
private Customer customer;
public Customer getCustomer() {
return customer;
}
public void create(Customer customer) {
em.persist(customer);
this.customer = customer;
}
public Customer find(Long id) {
this.customer = em.find(Customer.class, id);
System.out.println("customer managed ? " + em.contains(this.customer));
// Workaround :
// this.customer = em.merge(customer);
return customer;
}
public void remove(Long id) {
Customer cust = em.getReference(Customer.class, id);
em.remove(cust);
}
@TransactionAttribute(REQUIRES_NEW)
public void save() {
}
public List<Customer> findAllCustomers() {
Query query = em.createNamedQuery("Customer.all");
return query.getResultList();
}
@Remove
public void close() {
}
}
NetBeans 7.4、GlassFish 4.0、EJB 3.2、Java DB を使用しています。