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Posted to users@openjpa.apache.org by Henno Vermeulen <he...@huizemolenaar.nl> on 2011/02/21 13:00:21 UTC
RE: How to persist duplicate of an entity?
Sorry for replying to an old topic, but you are right. At the moment I also want to copy entities and I am running into the same problem with my serialize deserialize trick, even after setting id and version to null OpenJPA still thinks it is an existing entity, even though I don't use a detached state field and no detached state manager; OpenJPA still adds the pcVersionInit field and sets it to true.
I guess a copy constructor is the safest bet, or otherwise set it to false with Reflection which can get a bit tricky (I had multiple pcVersionInit fields in one entity, probably in superclasses or something).
Henno
-----Oorspronkelijk bericht-----
Van: Mark Struberg [mailto:struberg@yahoo.de]
Verzonden: vrijdag 14 januari 2011 18:15
Aan: users@openjpa.apache.org
Onderwerp: Re: How to persist duplicate of an entity?
btw, I found the default difference between a 'normally' detached entity and a serialisation/deserialisation detached entity pretty heavy.
This introduced several errors which were pretty hard to explain to an average-joe developer. An application by default might behave completely different if you run it on a local tomcat or in a cluster environment (with sessions getting replicated via memcached all the times). Another example would be using the JSF @ViewScoped (JSF2 ViewMap must get serialized with every request) vs e.g. @RequestScoped.
Because of that I'm currently in the process of switching to
openjpa.DetachState=loaded(DetachedStateField=true)
which hopefully will remove this obscurities.
As far as I understand, this will also restore the _pcVersionInit and others, isn't?
LieGrue,
strub
--- On Fri, 1/14/11, Rick Curtis <cu...@gmail.com> wrote:
> From: Rick Curtis <cu...@gmail.com>
> Subject: Re: How to persist duplicate of an entity?
> To: users@openjpa.apache.org
> Date: Friday, January 14, 2011, 5:03 PM
> > OpenJPA considers the entity a
> detached object even if you reset the Id
> and version field.
> In the absence of some sort of StateManager (Impl or
> Detached) we use the
> version field and another enhancer added field to detect
> whether an Entity
> is new or detached.
>
> > Might be a bit too stringent and the error message is
> misleading (read
> wrong).
> Misleading, probably.
>
> The problem is that we key off the fact that the version
> field was set. @See
> _pcVersionInit in an enhanced Entity. This field is used to
> differentiate
> between a uninitialized primitive and a primitive that was
> actually set to
> the default value (ie: setting an int version to zero). One
> way to get
> around this would be to serialize/deserialize an Entity
> after setting the
> version field. Or you could use reflection to set
> _pcVersionInit to
> false.... but neither options are good ones.
>
> This is a use case is one that wasn't considered when this
> code was written.
>
>
> Thanks,
> Rick..
>
> On Fri, Jan 14, 2011 at 10:47 AM, Mark Struberg <st...@yahoo.de>
> wrote:
>
> > I think this is perfectly ok with managed entities. It
> might of course work
> > with detached ones. Just remember that JPA is a ORM
> mapper. Thus a primary
> > key usually must not get changed.
> >
> > LieGrue,
> > strub
> >
> > --- On Fri, 1/14/11, Kevin Sutter <kw...@gmail.com>
> wrote:
> >
> > > From: Kevin Sutter <kw...@gmail.com>
> > > Subject: Re: How to persist duplicate of an
> entity?
> > > To: users@openjpa.apache.org
> > > Date: Friday, January 14, 2011, 4:20 PM
> > > You are right, Jerry... It
> > > looks like some recent changes to detect version
> > > field updates are preventing this type of
> processing.
> > > Even though the
> > > exception text makes it sound like we should be
> able to get
> > > around it...
> > >
> > > <openjpa-2.2.0-SNAPSHOT-r422266:1057901M
> nonfatal store
> > > error>
> > >
> org.apache.openjpa.persistence.EntityExistsException:
> > > Attempt to persist
> > > detached object
> "simple.model.Person@105a105a". If
> > > this is a new instance,
> > > make sure any version and/or auto-generated
> primary key
> > > fields are
> > > null/default when persisting.
> > > FailedObject: simple.model.Person@105a105a
> > >
> > > I tried with and without a version field.
> And, I
> > > tried with both primitive
> > > int and Integer version fields. No matter
> what I
> > > tried, I hit this
> > > exception either on the first or second commit of
> the
> > > Person instance. Even
> > > though I am not using auto-generated keys and my
> version
> > > field is either
> > > nulled out or zeroed out.
> > >
> > > Maybe this check is too stringent?
> > >
> > > Anyway, it sounds like this short cut won't work
> for
> > > Ognjen. Thanks for
> > > keeping me honest.
> > >
> > > Kevin
> > >
> > >
> > > On Fri, Jan 14, 2011 at 9:25 AM, No1UNo <je...@jerrycarter.org>
> > > wrote:
> > >
> > > >
> > > > In a recent application, I was forced to
> resort to a
> > > copy constructor to
> > > > explicitly make a copy of the object.
> I tried to
> > > reuse and re-persist an
> > > > entity after making a few changes, but any
> attempt to
> > > change the value of
> > > > the @Id was blocked by OpenJPA.
> > > >
> > > > On Jan 14, 2011, at 10:19 AM, Kevin Sutter
> [via
> > > OpenJPA] wrote:
> > > >
> > > > > There are so many variables that can
> come into
> > > play with a scenario like
> > > > > this...
> > > > >
> > > > > If you are only looking to populate the
> database
> > > and you don't care about
> > > > > the actual Entity objects, then you
> could just
> > > populate a single Entity
> > > > > instance. In a loop, persist and
> commit
> > > this entity, update the key and
> > > > > repeat. If you are using a
> Version field,
> > > then you'll also have to reset
> > > > > that each time.
> > > > >
> > > > > It all depends on the end game...
> :-)
> > > > >
> > > > > Kevin
> > > > >
> > > > > On Fri, Jan 14, 2011 at 8:52 AM, Henno
> Vermeulen
> > > <[hidden email]>wrote:
> > > > >
> > > > > > The easiest way that I found to
> create a
> > > deep clone of an object graph
> > > > is
> > > > > > to use apache commons
> collections.
> > > > > >
> > >
> SerializationUtils.deserialize(SerializationUtils.serialize(object)).
> > > > > >
> > > > > > Can of course also be used for a
> simple
> > > entity without relations. In
> > > > anyway
> > > > > > you have to watch out that you
> still set all
> > > primary keys to null. (May
> > > > also
> > > > > > not be most performant way.)
> > > > > >
> > > > > > Regards,
> > > > > > Henno Vermeulen
> > > > > > Huize Molenaar
> > > > > >
> > > > > > -----Oorspronkelijk bericht-----
> > > > > > Van: Ognjen Blagojevic
> [mailto:[hidden
> > > email]]
> > > > > > Verzonden: vrijdag 14 januari 2011
> 15:12
> > > > > > Aan: [hidden email]
> > > > > > Onderwerp: How to persist
> duplicate of an
> > > entity?
> > > > > >
> > > > > > Hi,
> > > > > >
> > > > > > Is there an easy way to create
> duplicate of
> > > an entity?
> > > > > >
> > > > > > I want to read entity from the DB,
> and then
> > > persist (almost) identical
> > > > > > copy. Every field should be the
> same, except
> > > primary key.
> > > > > >
> > > > > > I know I could probably use
> > > BeanUtils.copyProperties, but is there
> > > > > > OpenJPA preffered way to do the
> > > duplication?
> > > > > >
> > > > > > Regards,
> > > > > > Ognjen
> >
> >
> >
> >
>
Re: How to persist duplicate of an entity?
Posted by Rick Curtis <cu...@gmail.com>.
Henno -
> I'm not sure though how this relates to the duplicate entity problem?
After reading through the chain of notes, really it doesn't.
> I guess the pcVersionInit is a useful field for normal operation and
should still be serialized?
It was a conscious decision to not serialize pcVersionInit as we didn't want
to break existing behavior (serialize an enhanced Entity and deserialize it
into an unenhanced Entity).
Thanks,
Rick
On Mon, Feb 21, 2011 at 9:25 AM, Henno Vermeulen <he...@huizemolenaar.nl>wrote:
> Yes I can and I shall use this for any further bug reports I may do.
> I'm not sure though how this relates to the duplicate entity problem? I
> guess the pcVersionInit is a useful field for normal operation and should
> still be serialized?
>
> I already verified that the problem that OpenJPA does not recognize an
> entity that is duplicated with serialization (and id and version set to
> null) as a new one
> is solved by using reflection to set all "pcVersionInit" fields in the
> inheritance hierarchy to false. (I had a mapped superclass which also had
> this field).
>
> Henno
>
> -----Oorspronkelijk bericht-----
> Van: Rick Curtis [mailto:curtisr7@gmail.com]
> Verzonden: maandag 21 februari 2011 16:14
> Aan: users@openjpa.apache.org
> Onderwerp: Re: How to persist duplicate of an entity?
>
> Henno -
>
> Can you give 2.1.0 a try?
>
> Thanks,
> Rick
>
> On Mon, Feb 21, 2011 at 8:51 AM, Henno Vermeulen <henno@huizemolenaar.nl
> >wrote:
>
> > I am using version 2.0.0
> >
> > (downloaded through Maven
> > ...
> > <dependency>
> >
> > <groupId>org.apache.openjpa</groupId>
> >
> > <artifactId>openjpa-all</artifactId>
> > <version>2.0.0</version>
> > </dependency>
> > ...
> >
> > Regards,
> > Henno
> >
> >
> > -----Oorspronkelijk bericht-----
> > Van: Rick Curtis [mailto:curtisr7@gmail.com]
> > Verzonden: maandag 21 februari 2011 15:49
> > Aan: users@openjpa.apache.org
> > Onderwerp: Re: How to persist duplicate of an entity?
> >
> > Henno --
> >
> > What version of openjpa are you using?
> >
> > Thanks,
> > Rick
> >
>
RE: How to persist duplicate of an entity?
Posted by Henno Vermeulen <he...@huizemolenaar.nl>.
Yes I can and I shall use this for any further bug reports I may do.
I'm not sure though how this relates to the duplicate entity problem? I guess the pcVersionInit is a useful field for normal operation and should still be serialized?
I already verified that the problem that OpenJPA does not recognize an entity that is duplicated with serialization (and id and version set to null) as a new one
is solved by using reflection to set all "pcVersionInit" fields in the inheritance hierarchy to false. (I had a mapped superclass which also had this field).
Henno
-----Oorspronkelijk bericht-----
Van: Rick Curtis [mailto:curtisr7@gmail.com]
Verzonden: maandag 21 februari 2011 16:14
Aan: users@openjpa.apache.org
Onderwerp: Re: How to persist duplicate of an entity?
Henno -
Can you give 2.1.0 a try?
Thanks,
Rick
On Mon, Feb 21, 2011 at 8:51 AM, Henno Vermeulen <he...@huizemolenaar.nl>wrote:
> I am using version 2.0.0
>
> (downloaded through Maven
> ...
> <dependency>
>
> <groupId>org.apache.openjpa</groupId>
>
> <artifactId>openjpa-all</artifactId>
> <version>2.0.0</version>
> </dependency>
> ...
>
> Regards,
> Henno
>
>
> -----Oorspronkelijk bericht-----
> Van: Rick Curtis [mailto:curtisr7@gmail.com]
> Verzonden: maandag 21 februari 2011 15:49
> Aan: users@openjpa.apache.org
> Onderwerp: Re: How to persist duplicate of an entity?
>
> Henno --
>
> What version of openjpa are you using?
>
> Thanks,
> Rick
>
Re: How to persist duplicate of an entity?
Posted by Rick Curtis <cu...@gmail.com>.
Henno -
Can you give 2.1.0 a try?
Thanks,
Rick
On Mon, Feb 21, 2011 at 8:51 AM, Henno Vermeulen <he...@huizemolenaar.nl>wrote:
> I am using version 2.0.0
>
> (downloaded through Maven
> ...
> <dependency>
>
> <groupId>org.apache.openjpa</groupId>
>
> <artifactId>openjpa-all</artifactId>
> <version>2.0.0</version>
> </dependency>
> ...
>
> Regards,
> Henno
>
>
> -----Oorspronkelijk bericht-----
> Van: Rick Curtis [mailto:curtisr7@gmail.com]
> Verzonden: maandag 21 februari 2011 15:49
> Aan: users@openjpa.apache.org
> Onderwerp: Re: How to persist duplicate of an entity?
>
> Henno --
>
> What version of openjpa are you using?
>
> Thanks,
> Rick
>
RE: How to persist duplicate of an entity?
Posted by Henno Vermeulen <he...@huizemolenaar.nl>.
I am using version 2.0.0
(downloaded through Maven
...
<dependency>
<groupId>org.apache.openjpa</groupId>
<artifactId>openjpa-all</artifactId>
<version>2.0.0</version>
</dependency>
...
Regards,
Henno
-----Oorspronkelijk bericht-----
Van: Rick Curtis [mailto:curtisr7@gmail.com]
Verzonden: maandag 21 februari 2011 15:49
Aan: users@openjpa.apache.org
Onderwerp: Re: How to persist duplicate of an entity?
Henno --
What version of openjpa are you using?
Thanks,
Rick
Re: How to persist duplicate of an entity?
Posted by Rick Curtis <cu...@gmail.com>.
Henno --
What version of openjpa are you using?
Thanks,
Rick