[jboss-jira] [JBoss JIRA] (WFLY-10520) Add Hibernate ORM 5.3 compatibility transformer

[Gail Badner (JIRA)]

    [ https://issues.jboss.org/browse/WFLY-10520?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13597335#comment-13597335 ] 

Gail Badner commented on WFLY-10520:
------------------------------------

[~smarlow], regarding {{setFirstResult( -1 )}}, I'd like to clarify what I've done and why.

If (untransformed) {{org.hibernate.Query#setFirstResult( int )}} is called with a negative argument...

In 5.1,
* {{org.hibernate.Query#getFirstResult( )}} will return the same negative value;
* when the query is executed, the first result retrieved will be at position 0 of the query results.

In 5.3, 
* {{IllegalArgumentException}} is thrown as specified by JPA.

I could not restore both 5.1 behaviors in 5.3 (at least not without an overly complicated fix). I was able to restore the more important behavior (IMO) by calling {{setHibernateFirstResult( 0 )}}. By doing that, when the query is executed, the first result retrieved will be at position 0 of the query results.

I did this because I didn't think it should be necessary for an application to be modified because it calls  {{org.hibernate.Query#setFirstResult( int )}} with a negative argument, when it is easy for the transformer to do the right thing with respect to pagination.

After transforming, pagination will work the same as in 5.1, but  {{org.hibernate.Query#getFirstResult()}} will return 0, instead of the negative value the application used when it called {{org.hibernate.Query#setFirstResult( int )}}.

I think it is unlikely that an application would even call {{org.hibernate.Query#getFirstResult()}}, but if it does, it will get an unexpected result, (0). 

IMO, this can be handled by documenting this point {org.hibernate.Query#setHibernateFirstResult}} in the migration guide, as well as in the transformer documentation. It is already documented in the Javadoc. I suppose that Hibernate could also log an INFO or WARNING message when {{setHibernateFirstResult}} is called with a negative value.

> Add Hibernate ORM 5.3 compatibility transformer
> -----------------------------------------------
>
>                 Key: WFLY-10520
>                 URL: https://issues.jboss.org/browse/WFLY-10520
>             Project: WildFly
>          Issue Type: Task
>          Components: JPA / Hibernate
>            Reporter: Gail Badner
>            Assignee: Scott Marlow
>             Fix For: 14.0.0.CR1
>
>
> A compatibility transformer needs to be added to address Hibernate ORM 5.3 API methods that are no longer compatible with 5.1.
> From https://docs.google.com/document/d/1cAVBdeQXQfpTwH0f_GKSahh_gRd7bKI6kII-wxoMglU
> # Change call to org.hibernate.BasicQueryContract.getFlushMode() to instead call BasicQueryContract.getHibernateFlushMode().
> # Change call to org.hibernate.Session.getFlushMode, to instead call Session.getHibernateFlushMode()
> # Modify calls to org.hibernate.Query.getFirstResult() to convert returned int, to Integer result.
> # Modify calls to org.hibernate.Query.getMaxResults() to convert returned int, to Integer result, if returned int value is <= 0, null should be used, if Integer.MAX_VALUE is, the transformer should replace with null reference.
> # App References to Enum org.hibernate.FlushMode.NEVER (0) should be transformed to reference FlushMode.MANUAL (0) instead.   
> # For call to org.hibernate.Query.setMaxResults(int), instead call org.hibernate.Query.setHibernateMaxResults(int) which will be added soon to ORM 5.3.



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