[jira] Commented: (OPENJPA-514) Problems with the openjpa.RestoreState property

["Craig Russell (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/OPENJPA-514?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12568259#action_12568259 ] 

Craig Russell commented on OPENJPA-514:
---------------------------------------

I found that section 5.1 of the latest online manual http://openjpa.apache.org/docs/latest/manual/manual.html describes restoreState behavior.

It sounds from the description like this only applies to non-transaction-scoped (extended) persistence contexts. It talks about instances reloading state from the database, which is only applicable for extended persistence contexts.

I can't think of a good reason to do anything special with transaction-scoped persistence contexts, in which instances are detached at transaction completion. 

I'd rewrite the 5.1 to explicitly state that this behavior only applies to extended persistence contexts. And if OpenJPA does anything based on this flag in transaction-scoped persistence contexts, it probably should not.

And one question as to your wording:
>In fact, two central statements in the above cited passages from the  OpenJPA manual are not true. 

Are you implying that the statements are not true and should be changed, or that the implementation has a bug and the documentation is ok?

> Problems with the openjpa.RestoreState property
> -----------------------------------------------
>
>                 Key: OPENJPA-514
>                 URL: https://issues.apache.org/jira/browse/OPENJPA-514
>             Project: OpenJPA
>          Issue Type: Bug
>    Affects Versions: 1.1.0
>         Environment: Windows, at OpenJPA revision 619978
>            Reporter: David Ezzio
>         Attachments: TestCasesOpenJPA-514.zip
>
>
> Section 3.3.2 of the JPA spec is clear that upon rollback, all managed
> instances become detached, and in their detached state they may not be
> consistent or reusable as normally detached instances would be.
> OpenJPA has a property "openjpa.RestoreState" for which it claims a much
> stronger behavior. In section 5.6.1, the OpenJPA manual says:
>     "While the JPA specification says that you should not use rolled
>     back objects, such objects are perfectly valid in OpenJPA. You can
>     control whether the objects' managed state is rolled back to its
>     pre-transaction values with the openjpa.RestoreState configuration
>     property. none does not roll back state (the object becomes hollow,
>     and will re-load its state the next time it is accessed), immutable
>     restores immutable values (primitives, primitive wrappers, strings)
>     and clears mutable values so that they are reloaded on next access,
>     and all restores all managed values to their pre-transaction state."
>     
> In section 2.5.53, the OpenJPA manual identifies three values for the
> the openjpa.RestoreState value. It identifies "none" as the default
> value.
> In fact, two central statements in the above cited passages from the
> OpenJPA manual are not true.  In addition, the behavior in restoring
> fields is controlled at least in part by other factors.
> To begin with, a detached object will not reload any state. In the
> second instance, the default value appears to be "immutable" instead of
> "none".
> Two test cases were run with the entity class Dohickey. Dohickey has two
> string fields, lazy and eager, as well as an integer identity field.
> Both test cases use a new entity manager. In the first test case, the
> lazy field is dirtied in a newly found a Dohickey. In the second test
> case, the lazy field is dirtied after dirtying the eager field in a
> newly found Dohickey. In both test cases, the transaction is rolled
> back. The detached Dohickey is then tested for detachment, and for
> whether the values of the eager and lazy fields match the values in the
> database.
> Number Test case    RestoreState    Restored Eager  Restored Lazy
> ------+------------+---------------+--------------+--------------          
>  1     Lazy only     undefined       db value        dirty value
>  2     Lazy only     none            null            null
>  3     Lazy only     immutable       db value        dirty value
>  4     Eager first   undefined       db value        null
>  5     Eager first   none            null            null
>  6     Eager first   immutable       db value        null
> Test cases 1, 3, 4, and 6 indicate that the default value is likely
> "immutable". 
> Test cases 2 and 5 indicate that the "none" value behaves as described
> after correcting the statement that fields will be reloaded.
> The test cases indicate that the behavior for "immutable" setting does
> not work as expected, since the behavior depends on whether the field is
> eagerly or lazily loaded (and perhaps on fetch group configurations as
> well.)

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