Thanks, that's exactly the approach I'd taken and it works fine.
----- Original Message -----
From: "Justis Peters" <[EMAIL PROTECTED]>
To: "OJB Users List" <[EMAIL PROTECTED]>
Sent: Thursday, October 09, 2003 4:22 PM
Subject: Re: ConcurrentModificationException
> To be really careful about closing the broker, you may want to include a
try/finally structure. Here is Charles' code modified:
>
> public void onEvent() {
> PersistenceBroker pb =
PersistenceBrokerFactory.defaultPersistenceBroker();
> try {
> pb.store(this); // or whatever it is you want to do with the
broker
> } finally {
> pb.close();
> }
> }
>
> Charles Anthony [EMAIL PROTECTED] wrote:
> > Hi,
> >
> > You need to ensure that you are closing the broker.
> >
> > public void onEvent(){
> > PersistenceBroker pb =
> > PersistenceBrokerFactory.defaultPersistenceBroker();
> > pb.store(this); // or whatever it is you want to do with the broker
> > pb.close();
> > }
> >
> >
> > You should only get brokers when you need them, and close them when
you've
> > finished with them.
> >
> > HTH,
> >
> > Charles.
> >
> > > -----Original Message-----
> > > From: Michael Watson [mailto:[EMAIL PROTECTED]
> > > Sent: 09 October 2003 12:53
> > > To: OJB Users List; [EMAIL PROTECTED]
> > > Subject: Re: ConcurrentModificationException
> > >
> > >
> > > Hi Armin,
> > > I have an object with an init method where I assign a
> > > PersistenceBroker
> > > instance using
> > >
> > > PersistenceBrokerFactory.defaultPersistenceBroker()
> > >
> > > This object then has an onEvent() method that is called and uses
> > > broker.store().
> > >
> > > I tried modifying the object so that the broker is obtained
> > > in the onEvent
> > > instead of the init and I started getting
> > > "Borrow broker from pool failed" Exceptions. I have my
> > > connection-pool set
> > > up as follows:
> > >
> > > <connection-pool maxActive="-1" whenExhaustedAction="2"
> > > validationQuery="select 1 from t_client"/>
> > >
> > > Do you have any suggestions for what I might be doing wrong?
> > >
> > > Mike
> > >
> > > ----- Original Message -----
> > > From: "Armin Waibel" <[EMAIL PROTECTED]>
> > > To: "OJB Users List" <[EMAIL PROTECTED]>
> > > Sent: Wednesday, October 08, 2003 6:02 PM
> > > Subject: Re: ConcurrentModificationException
> > >
> > >
> > > > Hi Michael,
> > > >
> > > > On Wed, 8 Oct 2003 17:31:15 +0100, Michael Watson
> > > > <[EMAIL PROTECTED]> wrote:
> > > >
> > > > > Hi all,
> > > > >
> > > > > I'm finding I quite reguarly get this exception when I'm
> > > attempting to
> > > > > call
> > > > > PersistenceBroker.store(Object) from multiple threads
> > > simultaneously.
> > > > >
> > > > Do several threads share the same PB instance?
> > > > If so, this is not allowed. PB instances are not
> > > > threadsafe itself, but they are pooled so it's no
> > > > performance impact to use a separate PB instance for each thread.
> > > >
> > > > regards,
> > > > Armin
> > > >
> > > > > <?xml version='1.0'?>
> > > > > <exception>
> > > > > <cause>
> > > > > <detailMessage/>
> > > > >
> > > <exceptionClass>java.util.ConcurrentModificationException</exc
> > > eptionClass>
> > > > > <stackTrace>
> > > > >
> > > <stackTrace>java.util.AbstractList$Itr.checkForComodification(
> > > AbstractList.j
> > > > > ava:444)</stackTrace>
> > > > >
> > > <stackTrace>java.util.AbstractList$Itr.next(AbstractList.java:
> > > 417)</stackTra
> > > > > ce>
> > > > >
> > > <stackTrace>java.util.AbstractCollection.remove(AbstractCollec
> > > tion.java:250)
> > > > > </stackTrace>
> > > > >
> > > <stackTrace>org.apache.ojb.broker.core.PersistenceBrokerImpl.s
> > > tore(Unknown
> > > > > Source)</stackTrace>
> > > > >
> > > <stackTrace>org.apache.ojb.broker.core.PersistenceBrokerImpl.s
> > > tore(Unknown
> > > > > Source)</stackTrace>
> > > > >
> > > <stackTrace>org.apache.ojb.broker.core.DelegatingPersistenceBr
> > > oker.store(Unk
> > > > > nown Source)</stackTrace>
> > > > > ...
> > > > > </stackTrace>
> > > > > </cause>
> > > > > <detailMessage>Failed to update History record
> > > > > java.util.ConcurrentModificationException</detailMessage>
> > > > >
> > > <exceptionClass>org.apache.ojb.broker.PersistenceBrokerExcepti
> > > on</exceptionC
> > > > > lass>
> > > > > <stackTrace/>
> > > > > </exception>
> > > > >
> > > > > Obviously somewhere in the broker there's been an attempt
> > > to modify the
> > > > > structure of a list by 2 or more threads simultaneously.
> > > > >
> > > > > My question is, has anything been done to prevent this in a newer
> > > > > version or
> > > > > should I just catch these exceptions and retry the store?
> > > > >
> > > > > I'm using ojb-1.0.rc3 at the moment.
> > > > >
> > > > > Regards,
> > > > >
> > > > > Mike
> > > > >
> > > > >
> > > > >
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> > > >
> > > >
> > > >
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