At first I put it in the web services forum because I'm actually using google cloud endpoints. Probably the BigTable forum would be a good option indeed.
I can't tell precisely whether or not the A object has been retrieved, but because of the message I'd say it is.
Here is the code I'm using to run the retrieval:
@ApiMethod(name = "getA")
public A getA(@Named("id") String id) {
EntityManager mgr = getEntityManager();
A a = null;
try {
a = mgr.find(A.class, id);
} finally {
mgr.close();
}
return a;
}
Also, here is my persistence unit configuration:
<persistence-unit name="transactions-optional">
<provider>org.datanucleus.api.jpa.PersistenceProviderImpl</provider>
<properties>
<property name="datanucleus.NontransactionalRead" value="true"/>
<property name="datanucleus.NontransactionalWrite" value="true"/>
<property name="datanucleus.ConnectionURL" value="appengine"/>
<property name="datanucleus.appengine.datastoreEnableXGTransactions" value="true"/>
</properties>
</persistence-unit>
The datastoreEnableXGTransactions thing has to do with datastore entity groups. It allows one single transaction to operate over entity from up to 5 groups. At the moment I guess I need it because the B objects, children from A, are uowned. But I'm studying some different options too. Any comments on this would be appreciated.
Rodrigo.
