JPA Transaction management

[sachin y deshpande]

Hello,
We are developing an Application Managed JPA application.

The structure of the application is
Business Components which have business logic.
Tool generated DAO layer (JPA Managers and JPA Entities)

The usage would be like

 public class JPAEntity1 {
String x;
public String getX() {
return x;
}
setX(String _x) {
x = _x
}
}
public class JPAEntity2 {
String y;
public String getY() {
return y;
}
setY(String _y) {
y = _y
}
}
public class JPAEntity1Mgr {
update(JPAEntity1 obj) {
EntityManagerFactory emf = Persistence.createEntityManagerFactory("ZPU");
EntityManager em = emf.createEntityManager();
obj = em.merge(obj);
}
}
public class JPAEntity2Mgr {
update(JPAEntity2 obj) {
EntityManagerFactory emf = Persistence.createEntityManagerFactory("ZPU");
EntityManager em = emf.createEntityManager();
obj = em.merge(obj);
}
}
public class BusinessComponent {
operation(String x, String y) {
EntityManagerFactory emf = Persistence.createEntityManagerFactory("ZPU");
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
JPAEntity1MgrObj.update();
JPAEntity1MgrObj.update();
em.getTransaction().commit();
}
}

Note: JPA Managers do invoke any transaction related APIs.


1) Is this valid code? i.e. would the update happen in a single transaction even if the EntityManagers obtained by all the classes (BusinessComponent, JPAEntity2Mgr, JPAEntity1Mgr) are different?
2) Is there a need to invoke the em.joinTransaction() api in the JPA Managers?

[Amit Ghorpade]

"sachin yd " please check your private messages for an important administrative matter. You can check them by clicking the My Private Messages link above.

[sachin y deshpande]

Just updating the code (missed adding the objects to be persisted in the BusinessComponent code...)

class BusinessComponent {
operation(String x, String y) {
...
...
//get JPAEntity1 object;
//get JPAEntity2 object;
JPAEntity1Obj.setX(x);
JPAEntity2Obj.setY(y);
EntityManagerFactory emf = Persistence.createEntityManagerFactory("ZPU");
EntityManager em = emf.createEntityManager();
em.getTransaction().begin();
JPAEntity1MgrObj.update(JPAEntity1Obj);
JPAEntity1MgrObj.update(JPAEntity1Obj);
em.getTransaction().commit();
}
}