One more note regarding transactions with JPA: The actual DB changes aren't
made until the current transaction completes. Because of this, in my current
code I actually aggressively close the transaction so that I can catch
things like constraint violations. If you wait until the session ends to
close the transaction (via cleanup) then you won't be able to handle cases
like this. I have a helper method on my Model class that lets me run a
method inside its own transaction and handle any JPA-related exceptions. I'm
going to put it into the JPA tutorial, but here it is for now:
/**
This method allows me to clean up my code a bit and only handle
JPA-related exceptions.
An example usage would be:
def addFood(newFood : Food) =
wrapEM({
Model.persist(newFood)
S.redirectTo("/food/list")
}, {
case cve : ConstraintViolationException => S.error("That food already
exists!")
case _ => S.error("Internal error adding food")
})
Note that if I used normal try/catch then the wildcard match would trap
the RedirectException
thrown by S.redirectTo.
*/
def wrapEM(f : => Unit) : Unit = wrapEM(f, { case _ => /* nop */ })
def wrapEM[A](f : => A, handler : PartialFunction[Throwable, A]) : A = {
try {
val tx = getEM.getTransaction()
if (! tx.isActive() ) { tx.begin() }
try {
val ret : A = f
ret
} catch {
case he : HibernateException => {
this.error("Hibernate error", he)
handler(he)
}
case pe : PersistenceException => {
this.error("EM Error", pe)
handler(pe)
}
case sqle : java.sql.SQLException => {
this.error("SQL Exception", sqle)
handler(sqle)
}
} finally {
// make sure that we commit even with a redirectexception
if (tx.isActive() && ! tx.getRollbackOnly()) {
tx.commit()
} else if (tx.getRollbackOnly()) {
tx.rollback()
}
}
} catch {
// Special case. Usually we want to know why it failed to commit, not
just that it failed
case re : RollbackException => {
val (cause,message) = if (re.getCause() == null) {
(re,"No cause")
} else {
(re.getCause(), re.getCause().getMessage())
}
this.error("EM Commit error: {}", message)
this.error("Full trace", re)
handler(cause)
}
}
}
On Tue, Sep 30, 2008 at 5:25 PM, Derek Chen-Becker <[EMAIL PROTECTED]>wrote:
> I may have some time tomorrow to get it working. My initial goal is
> actually to get JNDI and JTA working in Jetty so that we have a dev
> environment that matches the production env.
>
> Derek
>
>
> On Tue, Sep 30, 2008 at 5:01 PM, Tim Perrett <[EMAIL PROTECTED]> wrote:
>
>>
>> Awesome - I personally would be very interested to hear how you got on
>> wtih hibernate proper.
>>
>> Perhaps you can bosh up a quick sample ;-)
>>
>> Cheers Kris
>>
>> Tim
>>
>> On Sep 30, 11:14 pm, "Kris Nuttycombe" <[EMAIL PROTECTED]>
>> wrote:
>> > Yup, Hibernate & JTA on Glassfish, also with EJB remoting.
>>
>> >>
>>
>
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