[hibernate-issues] [Hibernate-JIRA] Commented: (EJB-46) Property Validation should happen after PrePersist/PreUpdate

[Mark Menard (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/EJB-46?page=comments#action_24639 ] 

Mark Menard commented on EJB-46:
--------------------------------

Hi Emmanuel,

This patch fixes the following scenario. Create an entity with new (). Do not set the primary key. Call EntityManager.persist() on the new entity with a null primary key. The entity has a method marked with @PrePersist to set the primary key on the entity, but Hibernate checks the primary key before executing the @PrePersist method. Thus it throws an exception like the following:

Caused by: org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before calling save(): 
16:28:15,411 INFO  [STDOUT] net.vitarara.quadran.core.data.jpa.PartyJpaImpl
        at org.hibernate.id.Assigned.generate(Assigned.java:33)
        at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:98)
        at org.hibernate.event.def.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:131)
        at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:87)
        at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:38)
        at org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:618)
        at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:592)
        at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:596)
        at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:212)


If you could give me pointers on how to create a test scenario that would illustrate this I'd be happy to try, but I'll admit I'm a complete Hibernate novice.  The only experience I have with Hibernate was downloading Michal's patch, and applying it by hand to 3.2.0.RC2, building, and using the jars thus created.

> Property Validation should happen after PrePersist/PreUpdate
> ------------------------------------------------------------
>
>          Key: EJB-46
>          URL: http://opensource.atlassian.com/projects/hibernate/browse/EJB-46
>      Project: Hibernate Entity Manager
>         Type: Bug

>   Components: EntityManager
>     Versions: 3.1beta2, 3.1beta1
>  Environment: MySQL4, Sun JRE5, WinXP
>     Reporter: Johan Steiner
>  Attachments: EJB3EventListener.patch, EJB3EventListener_v2.patch
>
>
> Hi,
> the description is from http://forum.hibernate.org/viewtopic.php?t=944964 but I'm experiencing the exact same issue.
> *********************
> Hibernate does property validation such as not null checking before it does the EJB3 callback to prepersist/preupdate. I'm not sure if there's a good reason for this, but I think it would be particularly convenient if this behavior was reversed. IMHO it seems to better fit the semantics of the PRE callbacks, and it would allow callbacks to make modifications to the objects before they are persisted or updated -- modifications that might in turn effect the property validation Hibernate is doing.
> The "audit" example in the entity manager documentation does make changes to the object. What if these changes had effected the property validation done before the callback occurred? What if the object was in an invalid state before the callback, but a valid state after the callback? The latter case is what I think would be conveniently handled if hibernate did its property validation after prepersist/preupdate.
> Just two cents worth, obviously there are workarounds. This EJB3 stuff is looking great.
> Ryan
> P.S. This might also allow those of us who assign our own IDs to objects to do so automatically within a callback.
> *********************
> In my case I'm working with an entity like:
> public class MyEntity
> {
> 	@Basic(temporalType = TemporalType.TIMESTAMP)
> 	@Column(name = "$createdOn", insertable = true, updatable = false, nullable = false)
> 	private Date firstPersistedOn = null;
> 	@Basic(temporalType = TemporalType.TIMESTAMP)
> 	@Column(name = "$modifiedOn", insertable = true, updatable = false, nullable = true)
> 	private Date lastPersistedOn = null;
> 	@PrePersist
> 	public void onPrePersist()
> 	{
> 		firstPersistedOn = new Date();
> 	}
> 	@PreUpdate
> 	public void onPreUpdate()
> 	{
> 		lastPersistedOn = new Date();
> 	}
> }
> Hibernate throws:
> org.hibernate.PropertyValueException: not-null property references a null or transient value: MyEntity.firstPersistedOn
> 	at org.hibernate.engine.Nullability.checkNullability(Nullability.java:72)
> 	at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:262)
> 	at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:164)
> 	at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:114)
> 	at org.hibernate.event.def.DefaultMergeEventListener.entityIsTransient(DefaultMergeEventListener.java:167)
> 	at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:113)
> 	at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:60)
> 	at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:540)
> 	at org.hibernate.ejb.AbstractEntityManagerImpl.merge(AbstractEntityManagerImpl.java:139)
> Regards,
> Johan

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