Hi ,
Here is the cause of the issue:
getSelectSubclasses() of ValueMappingImpl.java is checking for criteria.
"return (_criteria) ? Select.SUBS_JOINABLE
: Select.SUBS_ANY_JOINABLE;"
If criteria is selected then "Select.SUBS_JOINABLE" is returned which will
generate a select statement that has subclass criteria ( in my E.g:
t0.ITEM_TYPE = ? )
If criteria is not selected then "Select.SUBS_ANY_JOINABLE" is returned
which will not generate the above condition.
So the question is if we have to make Select.SUBS_JOINABLE the default
behavior.
I think throwing class cast exception is bad and hence the default behavior
need to be changed to Select.SUBS_JOINABLE.
Thanks in advance,
Ravi.
rpalache wrote:
>
> Hi All,
>
> I have an openJPA application with following entities:
>
> "Item" Entity with SINGLE_TABLE inheritance strategy.
> DiscriminatorColumn on this ITEM_TYPE.
>
> "Book" and "Movie" entities extend "Item."
>
> "Artist" entity has 1-many relationship with "Book."
>
> The following results in classcastexception :
> Artist artist = em.find(Artist.class, "Herman Hess");
> List<Book> books= artist.getBooks();
>
> "artist.getBooks()" results in rows that contain both "Book" and"Movie"
> hence I get the following classcast :
> Exception in thread "main" java.lang.ClassCastException:
> org.apache.openjpa.enhance.model$Movie$pcsubclass
>
> When I add @ElementClassCriteria to the Artist to Book relationship then
> that resolves the issue.
> @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.EAGER,
> mappedBy="artist")
> @org.apache.openjpa.persistence.jdbc.ElementClassCriteria
> public List<Book> books;
>
> The reason for this issue is :
> without @ElementClassCriteria the SQL generated is :
> SELECT t0.UID1, t0.ITEM_TYPE, t0.title, t0.PAGE_COUNT FROM ITEM t0 WHERE
> t0.ARTIST = ?
> [params=(String) Herman Hess]
>
> With @ElementClassCriteria the SQL generated is :
> SELECT t0.UID1, t0.ITEM_TYPE, t0.title, t0.PAGE_COUNT FROM ITEM t0 WHERE
> t0.ARTIST = ? AND t0.ITEM_TYPE = ?
> [params=(String) Herman Hess, (String) BOOK]
>
> My questions regarding this is as follows:
>
> 1) @ElementClassCriteria is an openJPA specific annotation. Can I have a
> JPA specific solution for this problem ?
>
>
> 2) If I have a very big application(s) and lots of relations with the
> above described behavior.
> Then do I have to add it to each and every entity class that has the
> relationship ?
> Is there any property that I can define in the persistence.xml rather
> than in entities ?
>
> I have a simple testcase demonstrating the issue.
> I can upload it if needed.
>
> Regards,
> Ravi.
>
>
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