[jboss-user] [EJB 3.0] - EJB 3 Entity persist and merge bug?

[jlowcock]

I have a simple entity that uses a generated primary key.  If I simply persist the entity every thing works in terms of the database however the generated primary key value is not set in the class instance I have persisted.  If I persist and then merge the result the generated value is then set in my class instance however there are two row created in the database one for the first scenario and then one for the second scenario.  This implies to me that the persist operation is creating an internally cached version of the class which is then merged/copied when I call the merge operation.

Is there an operation I need to call after persist, or an additional annotation, or what, in order to have the generated value appear in the class instance without having to call merge.

Is the behaviour of the persist/merge combination a bug in that it creates two rows in the database?

Here is the code for my entity.

@Entity (name = "P002Ledger")
@Table	(name = "P002_LEDGER")
public class Ledger
  implements Serializable
{
  static 	final 
  private 	long	serialVersionUID	= -147023002293214496L;

  static	final
  private	Reporter	_reporter		= Reporter.getReporter(Ledger.class);
	
  private	long	m_code;
	
  private	String	m_name;
	
  public	Ledger	()
  {
		
  }
	
  public	Ledger	(long 	code)
  {
     m_code = code;
  }
	
  public	Ledger	(String	name)
  {
     m_name = name;
  }
	
  @Id
  @SequenceGenerator(name="p002_ledger_code_seq", allocationSize=25)
  @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="p002_ledger_code_seq")
  @Column (name="ledger_code",nullable=false)
  public 	long	getCode()
  {
     return m_code;
  }

  protected	void	setCode(long code)
  {
     m_code = code;
  }

  @PostPersist
  protected	void	askCode()
  {
     _reporter.trace("code = "+getCode());
  }
	
  @Column (name="ledger_name",nullable=false)
  public	String	getName()
  {
     return m_name;
  }
	
  public	void	setName(String name)
  {
     m_name = name;
  }
}



This is the code I have used to generate the persist/merge scenario.  The service methodsare simple wrappers around em.persist and em.merge.

Ledger ledger = new Ledger("Gen Barry");
service.insertLedger(ledger);
assertTrue(ledger.getCode() == 0);
ledger = service.updateLedger(ledger);
assertTrue(ledger.getCode() != 0);


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