Transaction Management with JBoss Seam + JPA (Hibernate) like Spring Framework

I'm a fan of using Spring framework for all my projects, but unfortunately on my current project, I have to add a module to an existing app already developed using JBoss Seam EJB3 and Hibernate, so this is what I did to work with the same model of ServiceImpl that Spring uses

This is the DAO (Existing) - I just added the save method
@Name("purchaseDao") @AutoCreate @Stateless @TransactionAttribute(TransactionAttributeType.REQUIRED) @TransactionManagement(TransactionManagementType.CONTAINER) public class PurchaseDAO_EJB3_Impl implements PurchaseDAO { private static Log log = LogFactory.getLog(PurchaseDAO_EJB3_Impl.class); @PersistenceContext(type = PersistenceContextType.TRANSACTION) private EntityManager em; .... public void save(Purchase instance) { log.debug("Saving "+instance); em.persist(instance); log.debug("Saved"); } } And this will be My Service (I will not include the Interfaces)
@Name("enrollmentDetailsServiceBean") @AutoCreate public class EnrollmentDetailsServiceImpl implements IEnrollmentDetailsService { private static Logger log = Logger.getLogger(EnrollmentDetailsServiceImpl.class); @In("purchaseDao") private PurchaseDAO purchaseDAO; /* * Service method which will handle the Transaction */ @Transactional(TransactionPropagationType.REQUIRED) public Boolean saveEnrollmentDetails(EnrollmentDetails enrollmentDetails) throws Exception { Boolean result = false; try{ log.debug("Transform "+enrollmentDetails+" into POJOs"); Purchase purchase = Transformer.transform(enrollmentDetails); log.debug("Start saving PURCHASE, PURCHASE_MODULE & TRANSACTION"); purchaseDAO.save(purchase); log.warn("Insert another POJO (which already exists on the table) to break this thing :P"); Purchase purchase2 = new Purchase(); purchaseDAO.save(purchase2); log.debug("Inserts completed!"); result = true; }catch (Exception ex) { log.error("Error while saving EnrollmentDetails into DB: PURCHASE, PURCHASE_MODULE, TRANSACTION",ex); throw ex; } return result; } }
By doing this we have the same model of Tx Management - Just by adding the 1 annotation to the method!!! Cool Isn't it?
Also, in case that you want to make your Tx ReadOnly, just add this annotation to your method (also)

org.jboss.seam.annotations.ReadOnly

Unfortunately the documentation for JBoss Seam is really poor on this aspect, so If anybody finds anything that could be improved, please let me know)

OneToMany Mapping

I faced this issue on August, let me explain you the situation, I had a Table called PURCHASE, with a 1:N Relationship with PURCHASE_MODULE and TRANSACTION tables

TRANSACTION >-----PURCHASE-----< PURCHASE_MODULE

First thing, How do I represent that using annotations (Hibernate): @Entity @Table(name = "PURCHASE") public class Purchase implements java.io.Serializable { @Id @Column(name = "ID", unique = true, nullable = false, insertable = true, updatable = true, precision = 10, scale = 0) public long getId() { return this.id; } ... @OneToMany(mappedBy="purchase", fetch=FetchType.LAZY) public List<Transaction> getTransactions() { return transactions; } @OneToMany(mappedBy="purchase", fetch=FetchType.LAZY) public List<PurchaseModule> getPurchaseModules() { return purchaseModules; } } @Entity @Table(name = "PURCHASE_MODULE") public class PurchaseModule implements java.io.Serializable { @ManyToOne(optional=false, fetch = FetchType.EAGER) @JoinColumn(name="PURCHASE_ID", referencedColumnName="id") private Purchase purchase; } @Entity @Table(name = "TRANSACTION") public class Transaction implements Serializable { @ManyToOne(optional=false, fetch = FetchType.EAGER) @JoinColumn(name="purchase_id", referencedColumnName="id") private Purchase purchase; }
Now what I want is each time I populate Purchase and set both List's (transactions and purchaseModules) and Invoke a SAVE for Purchase, the 3 tables will be impacted( there will be at least 3 INSERTs): purchaseDAO.save(purchase)
But this wasn't working as I expected, because no matter if I populated both ArrayList's (List) I never saw more than 1 Insert on my console.

Then the spark I was looking for! Inspiration came to me :P
On the Annotation @OneToMany there is an additional attribute I didn't include: cascade (The operations that must be cascaded to the target of the association)
@OneToMany(mappedBy="purchase", fetch=FetchType.LAZY, cascade=CascadeType.ALL) public List<Transaction> getTransactions() { return transactions; } @OneToMany(mappedBy="purchase", fetch=FetchType.LAZY, cascade=CascadeType.ALL) public List<PurchaseModule> getPurchaseModules() { return purchaseModules; }
On my case I don't care, so I just include ALL operations :P

ClassCastException with Hibernate: org.hibernate.type.DateType cannot be cast to org.hibernate.type.VersionType

I ran into a weird error when starting a Seam App with JPA (Hibernate) on JBoss

2011-08-03 14:30:17,938 [main] ERROR [org.jboss.deployment.scanner.URLDeploymentScanner] Incomplete Deployment listing:

--- MBeans waiting for other MBeans ---
ObjectName: persistence.units:ear=mainsite.ear,jar=kaptest_domain.jar,unitName=commonDatabase
  State: FAILED
  Reason: java.lang.ClassCastException: org.hibernate.type.DateType cannot be cast to org.hibernate.type.VersionType
  I Depend On:
    jboss.jca:service=DataSourceBinding,name=jdbc.CommonTransactionDS
  Depends On Me:
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=AdobeMeetingDAO_Seam_Impl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=AdobeProductDAO_Seam_Impl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=AdobeUserDAO_Seam_Impl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=AverageRatingServiceImpl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=BookstoreProductServiceImpl,service=EJB3
    jboss.j2ee:ear=mainsite.ear,jar=kaptest_domain.jar,name=BookstoreSearchServiceImpl,service=EJB3
...
...

WHAT??? java.lang.ClassCastException: org.hibernate.type.DateType cannot be cast to org.hibernate.type.VersionType

Anyway, for some reason, hibernate reverse engineer puts the @Version annotation to fields called timestamp as it expects it to be of type java.sql.Timestamp
Unfortunatly, my property was of type java.util.Date which is incomaptible with the @Version annotation. @Version @Temporal(TemporalType.DATE) @Column(name = "TIMESTAMP", length = 7) private Date timestamp;
I removed the @Version and it worked! @Temporal(TemporalType.DATE) @Column(name = "TIMESTAMP", length = 7) private Date timestamp;