> If I want to have generic code, how am I supposed to
> implement the createNamedQuery method? Do I leave the EM
> open forever? That doesn't seem right. So when am I
> supposed to close the EM?
1. Create an EM proxy. You've already got one, so we're good there.
2. The EM proxy should create a new EM for each persistence context. In
a tx, that means that it hangs onto the EM for the duration of the tx.
Outside a tx, that means that it keeps the EM open for the duration of
each operation.
For a find(), that's the duration of the stack execution.
For a query, that means you need to create a Query proxy also, and hand
off the EM created during createQuery() to the Query proxy. Then, the
Query proxy is responsible for closing the EM after
Query.getResultList() / Query.getSingleResult() is exectued.
-Patrick
--
Patrick Linskey
BEA Systems, Inc.
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> -----Original Message-----
> From: Dain Sundstrom [mailto:dain@iq80.com]
> Sent: Wednesday, April 25, 2007 10:04 AM
> To: open-jpa-dev@incubator.apache.org
> Subject: Re: Set query params without TX?
>
> On Apr 24, 2007, at 10:35 PM, Patrick Linskey wrote:
>
> > Yep -- you've gotta keep it open. If you want to support
> any JPA impl,
> > you need to have an EM proxy (please please please make it
> a dynamic
> > proxy that implements all the interfaces that the proxied thing
> > implements).
>
> That code is from my proxy.
>
> > If you're happy tying yourself to OpenJPA (or if you want
> to optimize
> > for OpenJPA), then you can use the openjpa.AutoDetach
> property to tell
> > OpenJPA how to handle non-transactional work. In that scenario, you
> > can keep a single EM per your delegating instance, and rely
> on OpenJPA
> > to do the transactional PC semantics.
>
> I just might give that a try.
>
> If I want to have generic code, how am I supposed to
> implement the createNamedQuery method? Do I leave the EM
> open forever? That doesn't seem right. So when am I
> supposed to close the EM?
>
> -dain
>
Notice: This email message, together with any attachments, may contain information of BEA
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this message in error, please immediately return this by email and then delete it.
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