EJB3.0 Entity cannot get attributes of extended class

Question

Hi ,
Have a very simple issue ..quite baisc one. So hopefully I"ll get an answer !
Am using EJB3.0 with WL10.3. Like any other application , every entity has id and version column. So I decided to put these fields in EntityBase.java
Other Entities will extend this entity .
For EG : Entity Organisation extends EntityBase. Organisation will have only other setter/getter for attributes. Setter/Getter for id/version will be in EntityBase. Application is deployed sucessfully and I dont get any exception, But when I try to getOrganisation Entity , id and version is null. Looks like WL is not able set id and version in EntityBase.
Am I missing something here ? How can we make an Entity extends any other class and at the same time tell the container to set/get inhertied values ? Code for EntityBase and Organisation goes something like below
public class EntityBase implements Serializable{
     private static final long serialVersionUID = 1L;
     // ---- Entity id
     @Id     
     @GeneratedValue(strategy=GenerationType.SEQUENCE ,generator="ID_SEQ")
     @SequenceGenerator(name="ID_SEQ" ,sequenceName="OBJECT_ID_SEQ" )
     @Column(name="ID")
     private int id ;
     public int getId() {
          return this.id;
     // ---- Entity version
     @Version
     private int version ;
     public int getVersion() { return this.version; }
Organisation.java is
@Entity
@Table(name="TYPED_T")
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public class Organisation extends EntityBase{
     private static final long serialVersionUID = 1L;
..setter/getter for other attributes
Thanks in advance

Answer 1

Hi, if you want your entity to inherit from a superclass that provides persistent entity state and mapping information, please use @MappedSuperclass.
You can find the definition and example from EJB3.0 Spec, chapter 2.1.9.2.
E.g.
@MappedSuperclass
public class Employee {
@Id protected Integer empId;
@Version protected Integer version;
@ManyToOne @JoinColumn(name="ADDR")
protected Address address;
public Integer getEmpId() { ... }
public void setEmpId(Integer id) { ... }
public Address getAddress() { ... }
public void setAddress(Address addr) { ... }
// Default table is FTEMPLOYEE table
@Entity
public class FTEmployee extends Employee {
// Inherited empId field mapped to FTEMPLOYEE.EMPID
// Inherited version field mapped to FTEMPLOYEE.VERSION
// Inherited address field mapped to FTEMPLOYEE.ADDR fk
// Defaults to FTEMPLOYEE.SALARY
protected Integer salary;
public FTEmployee() {}
public Integer getSalary() { ... }
public void setSalary(Integer salary) { ... }
Thanks,
Amy