Thank you for the additional insight.
Switching the DetachState is making things more clear. I had it set
to a value of "all" before based on some example (not sure where from
though).
Here are answers to your questions - Hopefully by the time I finish
answering them all, I will have it working.
1) It is detached.
2) SInce changing the value of DetachState, I now get an exception.
3) The instance is being converted with JAXB marshaller immediately
after being loaded from the database. So - no serialize/deserialize.
Here is the full routine that is loading the entity from the database
and marshalling it (slightly simplified):
public String sendXML(String projectID, User user) {
StringWriter xml = new StringWriter();
OpenJPAEntityManager em = getPM(entityManager);
FetchPlan plan = em.getFetchPlan();
plan.setMaxFetchDepth(0);
plan.clearFetchGroups();
plan.clearFields();
plan.addField(Project.class, "projectID");
plan.addField(Project.class, "projectNumber");
plan.addField(Project.class, "projectVersion");
plan.addField(Project.class, "projectRevision");
plan.addField(Project.class, "projectItem");
Project spec = em.find(Project.class, projectID);
spec = em.detach(spec);
try {
JAXBContext context = JAXBContext.newInstance(spec.getClass());
Marshaller m = context.createMarshaller();
m.marshal(spec, xml);
} catch (JAXBException je) {
System.out.println("JAXB Exception: " + je.getMessage());
je.printStackTrace();
} catch (Exception e) {
System.out.println("Some other exception doing JAXB conversion:
" +
e.getMessage());
e.printStackTrace();
}
System.out.println("XML: " + xml);
return xml.toString();
}
Well, I've gone through your questions - And, I am much closer (maybe)
to where I need to be. But, the 'm.marshall' call is trying to call
all of the getters of my entity. So, it is kicking out
IllegalStateExceptions since the fields are unloaded.
If I set the DetachState to something else, would I be able to get it
to simply return blanks/nulls for the unloaded fields?
Thanks again for you help so far,
Jay
On Tue, Mar 31, 2009 at 12:20 AM, Pinaki Poddar <[email protected]> wrote:
>
> Hi,
> You are correct in detaching the instance with the current fetch plan. In
> theory, now the detached instance should only have the fields selected by the
> fetch plan. If that is not happening then verify the following in order
> 1. Is the instance detached? OpenJPAEntityManager.isDetached(pc)
> 2. What happens if you access and fields that is not supposed to be loaded
> in the detached instance?
> Configure openjpa.DetachState [1] with AccessUnloaded to throw an exception
> on any attempt to acess any unloaded field.
> 3. If the detached instane is serialized and deserialized, which fields in
> the deserialized object are populated?
>
> The above steps to ascertain that when JAXB is xmlizing the instance,
> inadvertently no fields are getting loaded as a side-effect.
>
> You have to tell me more about the process that convertes these instances
> into XML -- such as when is this process is triggered? Which fields of the
> managed instance are processed by this XMLization process? Is there any
> possibility that a field will get loaded as a side-effect? Please note that
> any pc.getXXX() on a managed instance pc will load the field XXX.
>
>
> [1]
> http://openjpa.apache.org/builds/latest/docs/manual/manual.html#ref_guide_detach_behavior
>
> -----
> Pinaki Poddar http://ppoddar.blogspot.com/
>
> http://www.linkedin.com/in/pinakipoddar
> OpenJPA PMC Member/Committer
> JPA Expert Group Member
> --
> View this message in context:
> http://n2.nabble.com/%27Masking%27-fields-in-an-Entity-tp2545263p2561243.html
> Sent from the OpenJPA Users mailing list archive at Nabble.com.
>
>
