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Re: [eclipselink-users] Non-Entity types and TypedQuery / ClassCastExceptions
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JPA only understands entities with mappings, so if CountryHolder isn't an entity, it has no way of building what you want from what you've provided.
You can either work with the raw data returned in the object array, or specify the constructor to use in the JPQL like
entityManager.createQuery("SELECT new CountryHolder(v.country, COUNT(v.country)) cnt FROM Visit v GROUP BY v.country ORDER BY COUNT(v.country)");
Best Regards,
Chris
On 2013-03-07, at 5:54 AM, Markus Eisele <myfear@xxxxxx> wrote:
> Hi all,
>
> I'm playing around with non-entity return types at the moment and
> constantly run into java.lang.ClassCastExceptions ..
>
> Given:
> TypedQuery<CountryHolder> query = entityManager.createQuery("SELECT
> v.country, COUNT(v.country) AS cnt FROM Visit v GROUP BY v.country
> ORDER BY COUNT(v.country)", CountryHolder.class);
> List<CountryHolder> results = query.getResultList();
>
> keeps returning a list of Object[] but not the desired pojo (which has
> a public non-arg and a public CountryHolder(String country, Integer
> cnt) constructor ...)
>
> Every try to iterate the List and cast to anything else than Object fails ...
>
> Running that query against the DB returns the expected two columns mit
> the names country and cnt ...
>
> Turning sql logging on gives an indication that the following sql is
> send to the database .. which in fact skips the "as cnt" part ...
>
> SELECT COUNTRY, COUNT(COUNTRY) FROM VISIT GROUP BY COUNTRY ORDER BY
> COUNT(COUNTRY) ASC
>
> I'm running GlassFish Server Open Source Edition 3.1.2.2 with Eclipse
> Persistence Services - 2.3.2.v20111125-r10461 against Apache Derby
> Network Client JDBC Driver Version: 10.8.2.2 - (1181258)
>
> Any ideas highly appreciated!
>
> Thanks,
> - Markus
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