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Hibernate-validator: @NotEmpty does not work for null values

Answer 1

+1 A:

First of all, "merge before save" doesn't make sense. You can use merge() instead of save() when appropriate, but merge() already returns a persistent instance - the following save() is pointless.

Secondly, merge() does not invoke pre-insert / pre-update event listeners by default as far as I know; thus validation never gets performed. You can work around this by manually specifying listener for merge event or manually invoking validatior prior to merging.

ChssPly76 2009-10-26 20:41:28

But with empty ("") value it works!!! I mean, validator detects the validation fail, even when call merge before save.

Alberthoven 2009-10-26 20:46:11

With empty string merge() saves your entity successfully (empty string is not null - so there's no Nullability exception). The following save() invokes the validator which fails due to @NotEmpty; the entire transaction is then rolled back.

ChssPly76 2009-10-26 20:49:29

How could I force to validate before merging? there is no event for merge in ValidateEventListener array

Alberthoven 2009-10-26 20:54:04

What array? I've posted a link in my answer above - you need to add a new `<event>` entry to your Hibernate configuration with event type being "merge". I would not necessarily recommend this, though - merge semantics is rather tricky. Why are you using it instead of, say, saveOrUpdate() in the first place?

ChssPly76 2009-10-26 20:59:16

My saveOrUpdate needs to call merge due to possible scenarios (...)Like I'm using annotations, I have no hibernate.cfg.xml file, but persistence.xml, where I define the following beans:- sessionFactory( org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean)- dataSource- transactionManagerand many interceptors....¿Where could I add my "merge" event? ¿which bean could accept <event type="merge"> <listener class="org.hibernate.validator.event.ValidateEventListener"/> </event>?

Alberthoven 2009-10-26 21:17:41

AnnotationSessionFactoryBean has an `eventListeners` parameter which is a map of listener classes keyed by event types. So, `<property name="eventListeners"><map><entry key="merge" value="org.hibernate.validator.event.ValidateEventListener"/></map></property>`. Check Spring documentation (Hibernate integration) for specific details.

ChssPly76 2009-10-26 21:24:59

Ummm, that is just what I did when I tried to register the merge listener... but I got an error loading the context:Caused by: java.lang.ArrayStoreException: org.hibernate.validator.event.ValidateEventListenerI have added the full trace to the question's body.

Alberthoven 2009-10-28 14:05:26

Hmm... It seems the problem is `ValidateEventListener` does not implement `MergeEventListener` interface unlike, say, `PreInsertEventListener` so Hibernate can't assign it to `merge` event. You'll need to extend it, implement `MergeEventListener` and call through to `validate()` from `onMerge()`. Take a look at `ValidationEventListener.onPreInsert()` for an example. This goes back to "tricky merge event semantics"; perhaps you should consider invoking validator manually instead (check the link in my answer for details)

ChssPly76 2009-10-28 17:31:55

Ok, I will invoke the validation manually. Thanks!

Alberthoven 2009-11-03 09:11:14

Answer 2

A:

I got the same error which fixed itself once i did the following:

-public class CustomEventListener implements PreUpdateEventListener{...}

( instead of the earlier code which was: -public class CustomEventListener{..} )

scout 2010-05-28 06:51:34

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