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Posted to users@tapestry.apache.org by Henry Chen <he...@gmail.com> on 2005/05/17 08:43:59 UTC
Hibernate+Spring: OpenSessionInViewFilter problem
I have been searching around desperately for solution of handling
lazy-loading database objects in tapestry. I configured
OpenSessionInViewFilter for Tapestry pages. It worked for some cases
but not all. For example, in the table component, the first page was
good, but when I selected other pages, it gave me the
LazyInitialization exception - owning session was closed. Is there any
way around it now? Thanks a lot!
--
Thanks,
Henry Chen
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Re: Hibernate+Spring: OpenSessionInViewFilter problem
Posted by Shawn Church <sh...@boxity.com>.
Are you using Spring? I didn't have much luck using the OSIV filter
without also using Spring's HibernateDaoSupport (hibernateTemplate).
I've thought about trying something like the DataSqueezer approach, but
I can't see that as a complete solution. Maybe the way I use Tapestry
is unusual, but I like to drop my DAO objects directly into my Tapestry
pages, let Tapestry update the object properties as necessary, and then
explicitly save the object in my Tapestry page code. For example, if I
need to edit a certain Cat, I can do this:
Cat cat = getCatService().findByName("tom");
setCat (cat); // Tapestry page property
html:
<input jwcid="@TextField" value="ognl:cat.Color"/>
<input jwcid="submitContinue"/>
java:
// after necessary validations, etc.
cat.save();
I think the DataSqueezer approach would work best if you fetched a Cat,
copied each Cat property to individual page properties (ie - setColor(
cat.getColor()), modified those properties, used the DataSqueezer method
to re-fetch the original Cat, then performed explicit updates such as
cat.setColor(getColor()), and then cat.save(). For me, this would only
be useful maybe 20% of the time.
Shawn
Quoting Andreas Andreou <an...@di.uoa.gr>:
> Shawn Church wrote:
>
> >The problem with this is that it does not address the issue of
> >reattaching detached objects to the currently-open session. Since
> it is
> >natural in Tapestry to instantiate an object, use it in a page, and
> then
> >to persist the (potentially) changed object, the object must first
> be
> >reattached to the Hibernate session. Even if the object is not
> >persisted, if it contains lazy collection references it is necessary
> to
> >reattach the object in order for the collection to be properly
> initialized.
> >
> >
> 100% correct. That's why I'm also re-attaching those objects, though
> not
> using a HibernateService, but explicit DAO calls.
> Perhaps the 'best' solution is the one using custom DataSqueezers
>
http://wiki.apache.org/jakarta-tapestry/FrequentlyAskedQuestions/SpringHibernate
> but i have yet to try it...
>
> >The only reliable solution I have found is to use Spring's
> >OpenSessionInView filter with singleSession=true, and then to
> explicitly
> >reattach objects in pageBeginRender(). I use a custom
> HibernateService
> >class which implements methods for attach(), evict(), and merge().
> The
> >attach() method actually does a getSession().lock(object,
> >LockMode.NONE), but it handles NonUniqueObjectExceptions which will
> >commonly be thrown when using lazy collections if one of the
> collection
> >objects happens to already exist in the session.
> >
> >Shawn
> >
> >Quoting Andreas Andreou <an...@di.uoa.gr>:
> >
> >
> >
> >>Regarding to not using servlet filters for the OpenSessionInView
> >>approach, I can confirm that other approaches work!
> >>First of all,
> >>i've always used the HibernateUtil class posted in hibernate
> forums
> >>(and maybe also included in Hibernate in Action) that stores and
> >>gets
> >>session and transaction objects in thread local variables.
> >>
> >>So, opening a hibernate session is never a problem (whichever
> method
> >>first uses one, creates it) and so it only remains the issue of
> >>closing it
> >>somewhere.
> >>
> >>I haven't tried the cleanupAfterRequest() of Engine approach.
> >>Instead i've always extended the
> >>pageEndRender(PageEvent event)
> >>in a BasePage (that all my pages extend) and there I just do:
> >>
> >> super.pageEndRender(event);
> >> HibernateUtil.closeSession();
> >>
> >>The nice thing is that this closeSession() never complains, no
> >>matter
> >>if no session is found, or if it has already been closed.
> >>
> >>Anyway, I can post the HibernateUtil class here if you want to...
> >>Andreas
> >>
> >>Alejandro Scandroli wrote:
> >>
> >>
> >>
> >>>Henry Chen wrote:
> >>>
> >>>
> >>>
> >>>
> >>>>I have been searching around desperately for solution of
> handling
> >>>>lazy-loading database objects in tapestry. I configured
> >>>>OpenSessionInViewFilter for Tapestry pages. It worked for some
> >>>>
> >>>>
> >>cases
> >>
> >>
> >>>>but not all. For example, in the table component, the first page
> >>>>
> >>>>
> >>was
> >>
> >>
> >>>>good, but when I selected other pages, it gave me the
> >>>>LazyInitialization exception - owning session was closed. Is
> there
> >>>>
> >>>>
> >>any
> >>
> >>
> >>>>way around it now? Thanks a lot!
> >>>>
> >>>>
> >>>>
> >>>>
> >>>Hi , I'm having the same problem on Trails.
> >>>This quote may help.
> >>>
> >>>quote form Open Session in View discussion on Hibernate site.
> >>><quote>
> >>>Open Session pattern and Tapestry web framework
> >>>24 Mar 2004, 19:27 wassup
> >>>
> >>>If you develop your application with Tapestry framework it is
> >>>
> >>>
> >>better
> >>
> >>
> >>>do not use Servlet Filters to manage request cycle. More
> preferable
> >>>
> >>>
> >>to
> >>
> >>
> >>>override setupForRequest() and cleanupAfterRequest() of Engine
> >>>class.
> >>></quote>
> >>>
> >>>I have no time to try this.
> >>>Please let me know if it works for you, or if you find another
> >>>
> >>>
> >>workaround.
> >>
> >>
> >>>Saludos.
> >>>Alejandro.
> >>>
> >>>PD:- please, excuse my English.
> >>>
> >>>
> >>>
> >>>---------------------------------------------------------------------
> >>>To unsubscribe, e-mail:
> >>>
> >>>
> >>tapestry-user-unsubscribe@jakarta.apache.org
> >>
> >>
> >>>For additional commands, e-mail:
> >>>
> >>>
> >>tapestry-user-help@jakarta.apache.org
> >>
> >>
> >>>
> >>>
> >>>
> >>>
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> >>
> >>
> >>
> >
> >
> >
> >
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Re: Hibernate+Spring: OpenSessionInViewFilter problem
Posted by Andreas Andreou <an...@di.uoa.gr>.
Shawn Church wrote:
>The problem with this is that it does not address the issue of
>reattaching detached objects to the currently-open session. Since it is
>natural in Tapestry to instantiate an object, use it in a page, and then
>to persist the (potentially) changed object, the object must first be
>reattached to the Hibernate session. Even if the object is not
>persisted, if it contains lazy collection references it is necessary to
>reattach the object in order for the collection to be properly initialized.
>
>
100% correct. That's why I'm also re-attaching those objects, though not
using a HibernateService, but explicit DAO calls.
Perhaps the 'best' solution is the one using custom DataSqueezers
http://wiki.apache.org/jakarta-tapestry/FrequentlyAskedQuestions/SpringHibernate
but i have yet to try it...
>The only reliable solution I have found is to use Spring's
>OpenSessionInView filter with singleSession=true, and then to explicitly
>reattach objects in pageBeginRender(). I use a custom HibernateService
>class which implements methods for attach(), evict(), and merge(). The
>attach() method actually does a getSession().lock(object,
>LockMode.NONE), but it handles NonUniqueObjectExceptions which will
>commonly be thrown when using lazy collections if one of the collection
>objects happens to already exist in the session.
>
>Shawn
>
>Quoting Andreas Andreou <an...@di.uoa.gr>:
>
>
>
>>Regarding to not using servlet filters for the OpenSessionInView
>>approach, I can confirm that other approaches work!
>>First of all,
>>i've always used the HibernateUtil class posted in hibernate forums
>>(and maybe also included in Hibernate in Action) that stores and
>>gets
>>session and transaction objects in thread local variables.
>>
>>So, opening a hibernate session is never a problem (whichever method
>>first uses one, creates it) and so it only remains the issue of
>>closing it
>>somewhere.
>>
>>I haven't tried the cleanupAfterRequest() of Engine approach.
>>Instead i've always extended the
>>pageEndRender(PageEvent event)
>>in a BasePage (that all my pages extend) and there I just do:
>>
>> super.pageEndRender(event);
>> HibernateUtil.closeSession();
>>
>>The nice thing is that this closeSession() never complains, no
>>matter
>>if no session is found, or if it has already been closed.
>>
>>Anyway, I can post the HibernateUtil class here if you want to...
>>Andreas
>>
>>Alejandro Scandroli wrote:
>>
>>
>>
>>>Henry Chen wrote:
>>>
>>>
>>>
>>>
>>>>I have been searching around desperately for solution of handling
>>>>lazy-loading database objects in tapestry. I configured
>>>>OpenSessionInViewFilter for Tapestry pages. It worked for some
>>>>
>>>>
>>cases
>>
>>
>>>>but not all. For example, in the table component, the first page
>>>>
>>>>
>>was
>>
>>
>>>>good, but when I selected other pages, it gave me the
>>>>LazyInitialization exception - owning session was closed. Is there
>>>>
>>>>
>>any
>>
>>
>>>>way around it now? Thanks a lot!
>>>>
>>>>
>>>>
>>>>
>>>Hi , I'm having the same problem on Trails.
>>>This quote may help.
>>>
>>>quote form Open Session in View discussion on Hibernate site.
>>><quote>
>>>Open Session pattern and Tapestry web framework
>>>24 Mar 2004, 19:27 wassup
>>>
>>>If you develop your application with Tapestry framework it is
>>>
>>>
>>better
>>
>>
>>>do not use Servlet Filters to manage request cycle. More preferable
>>>
>>>
>>to
>>
>>
>>>override setupForRequest() and cleanupAfterRequest() of Engine
>>>class.
>>></quote>
>>>
>>>I have no time to try this.
>>>Please let me know if it works for you, or if you find another
>>>
>>>
>>workaround.
>>
>>
>>>Saludos.
>>>Alejandro.
>>>
>>>PD:- please, excuse my English.
>>>
>>>
>>>
>>>---------------------------------------------------------------------
>>>To unsubscribe, e-mail:
>>>
>>>
>>tapestry-user-unsubscribe@jakarta.apache.org
>>
>>
>>>For additional commands, e-mail:
>>>
>>>
>>tapestry-user-help@jakarta.apache.org
>>
>>
>>>
>>>
>>>
>>>
>>---------------------------------------------------------------------
>>To unsubscribe, e-mail: tapestry-user-unsubscribe@jakarta.apache.org
>>For additional commands, e-mail:
>>tapestry-user-help@jakarta.apache.org
>>
>>
>>
>
>
>
>
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>
>
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Re: IExternalPage & listener understanding
Posted by Pablo Ruggia <pr...@gmail.com>.
Are you linking to external service ? If you don't, then
activateExternalPage won't get called.
On 6/5/05, Tom <ta...@worldware.com> wrote:
> Hi -
>
> I just want to make sure I'm understanding things correctly.
>
> The situation:
> A page that implements IExternalPage, taking one parameter, that displays a
> blog component. The page also has a "logout" link with a listener.
>
> The problem:
> The logout listener doesn't get called when clicked, because an exception
> occurs in the blog component. This is apparently happening since
> activateExternalPage() is not getting called.
>
>
> My hypothesis:
> The listener invocation first rewinds the page, rendering the blog
> component, but does NOT pass in the parameters necessary to render the page.
>
> Ugly solution:
> Make sure that every page can render, even without required parameters,
> even when this is an error condition and should result in an exception, or
> error page being displayed.
>
> Better solution: I would think that since an external page requires
> parameters to render, they should be passed to the page when invoking a
> listener on that page. Am I missing something? Is there some standard way
> to handle this?
>
> Thanks,
>
> Tom
>
>
>
>
>
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Re: IExternalPage & listener understanding
Posted by Erik Hatcher <er...@ehatchersolutions.com>.
On Jun 5, 2005, at 9:48 PM, Tom wrote:
> Hi -
>
> I just want to make sure I'm understanding things correctly.
>
> The situation:
> A page that implements IExternalPage, taking one parameter, that
> displays a blog component. The page also has a "logout" link with a
> listener.
>
> The problem:
> The logout listener doesn't get called when clicked, because an
> exception occurs in the blog component. This is apparently
> happening since activateExternalPage() is not getting called.
activateExternalPage does not get invoked when clicking on a
DirectLink (which is what I assume your "logout" link is). Only
ExternalLink's call activateExternalPage.
> My hypothesis:
> The listener invocation first rewinds the page, rendering the blog
> component, but does NOT pass in the parameters necessary to render
> the page.
Right. You will have to account for this either by passing the
necessary parameters and setting them using PageValidateListener or
by making the parameters persistent.
> Better solution: I would think that since an external page requires
> parameters to render, they should be passed to the page when
> invoking a listener on that page. Am I missing something? Is there
> some standard way to handle this?
The standard ways are mentioned above. This is certainly an
interesting issue to debate though.
Erik
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IExternalPage & listener understanding
Posted by Tom <ta...@worldware.com>.
Hi -
I just want to make sure I'm understanding things correctly.
The situation:
A page that implements IExternalPage, taking one parameter, that displays a
blog component. The page also has a "logout" link with a listener.
The problem:
The logout listener doesn't get called when clicked, because an exception
occurs in the blog component. This is apparently happening since
activateExternalPage() is not getting called.
My hypothesis:
The listener invocation first rewinds the page, rendering the blog
component, but does NOT pass in the parameters necessary to render the page.
Ugly solution:
Make sure that every page can render, even without required parameters,
even when this is an error condition and should result in an exception, or
error page being displayed.
Better solution: I would think that since an external page requires
parameters to render, they should be passed to the page when invoking a
listener on that page. Am I missing something? Is there some standard way
to handle this?
Thanks,
Tom
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RE: Hibernate+Spring: OpenSessionInViewFilter problem
Posted by Shawn Church <sh...@boxity.com>.
This would work in simple cases, but there are some problems. First, if
foo references a lazy collection, the collection would not be accessible
after the evict(). Also, LockMode.NONE can only be used if foo is not
modified in any way.
So, if "Do some stuff" is simply "read some of foo's
non-lazily-initialized properties", then everything is fine.
If "Do some stuff" means "modify some of foo's non-lazily-initialized
properties", then you would have to use session.merge(). In Hibernate
2.x, the method was "saveOrUpdateCopy()", but in Hib 3 that method is
deprecated in favor of "merge()".
If "Do some stuff" means "iterate foo's lazily-initialized collection",
then you would have trouble since foo is no longer associated with an
open session.
You may also have some trouble with transaction-management issues (if
you are concerned about dao transactions), which is another reason
Spring has been helpful to me. With Spring, it is easy to define which
types of service methods need which types of transactional support. For
example, if you have a service method which needs to perform a set of
operations as a unit (update this, delete that), Spring manages the
details without requiring any special coding on your part.
If you don't mind having Hibernate operations intermingled with your
view-layer code, you might be able to get by without Spring. I prefer
to keep them separate, so my pages can just request and store data
without much regard for the lower-level details.
I am no Hibernate or Spring expert, but I haven't found any other way
that works 100% of the time. 95% is easy, but due to Hibernate's strict
nature it has not been easy for me to find a 100% solution. I'm open to
suggestions, but so far I'm pretty comfortable with this solution. If I
ever get a lazy init exception or a duplicate object exception, I've
most likely done something silly.
Shawn
Quoting Patrick Casey <pa...@adelphia.net>:
>
> Can't you just re-attach with lock?
>
> e.g.
>
> Session first = Configuration.createSession();
> Object foo = first.get(Foo.class, 24);
> first.evict(foo);
> ...
> Do some stuff
> ...
>
> Session second = Configuration.createSession();
> Second.lock(foo, LockMode.NONE);
> // you're now attached to second
>
>
> > -----Original Message-----
> > From: Shawn Church [mailto:shawn@boxity.com]
> > Sent: Wednesday, May 18, 2005 9:57 AM
> > To: Tapestry users
> > Subject: Re: Hibernate+Spring: OpenSessionInViewFilter problem
> >
> > The problem with this is that it does not address the issue of
> > reattaching detached objects to the currently-open session. Since
> it is
> > natural in Tapestry to instantiate an object, use it in a page, and
> then
> > to persist the (potentially) changed object, the object must first
> be
> > reattached to the Hibernate session. Even if the object is not
> > persisted, if it contains lazy collection references it is
> necessary to
> > reattach the object in order for the collection to be properly
> > initialized.
> >
> > The only reliable solution I have found is to use Spring's
> > OpenSessionInView filter with singleSession=true, and then to
> explicitly
> > reattach objects in pageBeginRender(). I use a custom
> HibernateService
> > class which implements methods for attach(), evict(), and merge().
> The
> > attach() method actually does a getSession().lock(object,
> > LockMode.NONE), but it handles NonUniqueObjectExceptions which
> will
> > commonly be thrown when using lazy collections if one of the
> collection
> > objects happens to already exist in the session.
> >
> > Shawn
> >
> > Quoting Andreas Andreou <an...@di.uoa.gr>:
> >
> > > Regarding to not using servlet filters for the OpenSessionInView
> > > approach, I can confirm that other approaches work!
> > > First of all,
> > > i've always used the HibernateUtil class posted in hibernate
> forums
> > > (and maybe also included in Hibernate in Action) that stores and
> > > gets
> > > session and transaction objects in thread local variables.
> > >
> > > So, opening a hibernate session is never a problem (whichever
> method
> > > first uses one, creates it) and so it only remains the issue of
> > > closing it
> > > somewhere.
> > >
> > > I haven't tried the cleanupAfterRequest() of Engine approach.
> > > Instead i've always extended the
> > > pageEndRender(PageEvent event)
> > > in a BasePage (that all my pages extend) and there I just do:
> > >
> > > super.pageEndRender(event);
> > > HibernateUtil.closeSession();
> > >
> > > The nice thing is that this closeSession() never complains, no
> > > matter
> > > if no session is found, or if it has already been closed.
> > >
> > > Anyway, I can post the HibernateUtil class here if you want
> to...
> > > Andreas
> > >
> > > Alejandro Scandroli wrote:
> > >
> > > >Henry Chen wrote:
> > > >
> > > >
> > > >>I have been searching around desperately for solution of
> handling
> > > >>lazy-loading database objects in tapestry. I configured
> > > >>OpenSessionInViewFilter for Tapestry pages. It worked for some
> > > cases
> > > >>but not all. For example, in the table component, the first
> page
> > > was
> > > >>good, but when I selected other pages, it gave me the
> > > >>LazyInitialization exception - owning session was closed. Is
> there
> > > any
> > > >>way around it now? Thanks a lot!
> > > >>
> > > >>
> > > >
> > > >Hi , I'm having the same problem on Trails.
> > > >This quote may help.
> > > >
> > > >quote form Open Session in View discussion on Hibernate site.
> > > ><quote>
> > > >Open Session pattern and Tapestry web framework
> > > >24 Mar 2004, 19:27 wassup
> > > >
> > > >If you develop your application with Tapestry framework it is
> > > better
> > > >do not use Servlet Filters to manage request cycle. More
> preferable
> > > to
> > > >override setupForRequest() and cleanupAfterRequest() of Engine
> > > >class.
> > > ></quote>
> > > >
> > > >I have no time to try this.
> > > >Please let me know if it works for you, or if you find another
> > > workaround.
> > > >
> > > >Saludos.
> > > >Alejandro.
> > > >
> > > >PD:- please, excuse my English.
> > > >
> > > >
> > > >
> > >
> >---------------------------------------------------------------------
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> > > tapestry-user-unsubscribe@jakarta.apache.org
> > > >For additional commands, e-mail:
> > > tapestry-user-help@jakarta.apache.org
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > >
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> >
> >
> >
> >
> >
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RE: Hibernate+Spring: OpenSessionInViewFilter problem
Posted by Patrick Casey <pa...@adelphia.net>.
Can't you just re-attach with lock?
e.g.
Session first = Configuration.createSession();
Object foo = first.get(Foo.class, 24);
first.evict(foo);
...
Do some stuff
...
Session second = Configuration.createSession();
Second.lock(foo, LockMode.NONE);
// you're now attached to second
> -----Original Message-----
> From: Shawn Church [mailto:shawn@boxity.com]
> Sent: Wednesday, May 18, 2005 9:57 AM
> To: Tapestry users
> Subject: Re: Hibernate+Spring: OpenSessionInViewFilter problem
>
> The problem with this is that it does not address the issue of
> reattaching detached objects to the currently-open session. Since it is
> natural in Tapestry to instantiate an object, use it in a page, and then
> to persist the (potentially) changed object, the object must first be
> reattached to the Hibernate session. Even if the object is not
> persisted, if it contains lazy collection references it is necessary to
> reattach the object in order for the collection to be properly
> initialized.
>
> The only reliable solution I have found is to use Spring's
> OpenSessionInView filter with singleSession=true, and then to explicitly
> reattach objects in pageBeginRender(). I use a custom HibernateService
> class which implements methods for attach(), evict(), and merge(). The
> attach() method actually does a getSession().lock(object,
> LockMode.NONE), but it handles NonUniqueObjectExceptions which will
> commonly be thrown when using lazy collections if one of the collection
> objects happens to already exist in the session.
>
> Shawn
>
> Quoting Andreas Andreou <an...@di.uoa.gr>:
>
> > Regarding to not using servlet filters for the OpenSessionInView
> > approach, I can confirm that other approaches work!
> > First of all,
> > i've always used the HibernateUtil class posted in hibernate forums
> > (and maybe also included in Hibernate in Action) that stores and
> > gets
> > session and transaction objects in thread local variables.
> >
> > So, opening a hibernate session is never a problem (whichever method
> > first uses one, creates it) and so it only remains the issue of
> > closing it
> > somewhere.
> >
> > I haven't tried the cleanupAfterRequest() of Engine approach.
> > Instead i've always extended the
> > pageEndRender(PageEvent event)
> > in a BasePage (that all my pages extend) and there I just do:
> >
> > super.pageEndRender(event);
> > HibernateUtil.closeSession();
> >
> > The nice thing is that this closeSession() never complains, no
> > matter
> > if no session is found, or if it has already been closed.
> >
> > Anyway, I can post the HibernateUtil class here if you want to...
> > Andreas
> >
> > Alejandro Scandroli wrote:
> >
> > >Henry Chen wrote:
> > >
> > >
> > >>I have been searching around desperately for solution of handling
> > >>lazy-loading database objects in tapestry. I configured
> > >>OpenSessionInViewFilter for Tapestry pages. It worked for some
> > cases
> > >>but not all. For example, in the table component, the first page
> > was
> > >>good, but when I selected other pages, it gave me the
> > >>LazyInitialization exception - owning session was closed. Is there
> > any
> > >>way around it now? Thanks a lot!
> > >>
> > >>
> > >
> > >Hi , I'm having the same problem on Trails.
> > >This quote may help.
> > >
> > >quote form Open Session in View discussion on Hibernate site.
> > ><quote>
> > >Open Session pattern and Tapestry web framework
> > >24 Mar 2004, 19:27 wassup
> > >
> > >If you develop your application with Tapestry framework it is
> > better
> > >do not use Servlet Filters to manage request cycle. More preferable
> > to
> > >override setupForRequest() and cleanupAfterRequest() of Engine
> > >class.
> > ></quote>
> > >
> > >I have no time to try this.
> > >Please let me know if it works for you, or if you find another
> > workaround.
> > >
> > >Saludos.
> > >Alejandro.
> > >
> > >PD:- please, excuse my English.
> > >
> > >
> > >
> > >---------------------------------------------------------------------
> > >To unsubscribe, e-mail:
> > tapestry-user-unsubscribe@jakarta.apache.org
> > >For additional commands, e-mail:
> > tapestry-user-help@jakarta.apache.org
> > >
> > >
> > >
> > >
> >
> >
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> > tapestry-user-help@jakarta.apache.org
> >
>
>
>
>
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Re: Hibernate+Spring: OpenSessionInViewFilter problem
Posted by Shawn Church <sh...@boxity.com>.
The problem with this is that it does not address the issue of
reattaching detached objects to the currently-open session. Since it is
natural in Tapestry to instantiate an object, use it in a page, and then
to persist the (potentially) changed object, the object must first be
reattached to the Hibernate session. Even if the object is not
persisted, if it contains lazy collection references it is necessary to
reattach the object in order for the collection to be properly initialized.
The only reliable solution I have found is to use Spring's
OpenSessionInView filter with singleSession=true, and then to explicitly
reattach objects in pageBeginRender(). I use a custom HibernateService
class which implements methods for attach(), evict(), and merge(). The
attach() method actually does a getSession().lock(object,
LockMode.NONE), but it handles NonUniqueObjectExceptions which will
commonly be thrown when using lazy collections if one of the collection
objects happens to already exist in the session.
Shawn
Quoting Andreas Andreou <an...@di.uoa.gr>:
> Regarding to not using servlet filters for the OpenSessionInView
> approach, I can confirm that other approaches work!
> First of all,
> i've always used the HibernateUtil class posted in hibernate forums
> (and maybe also included in Hibernate in Action) that stores and
> gets
> session and transaction objects in thread local variables.
>
> So, opening a hibernate session is never a problem (whichever method
> first uses one, creates it) and so it only remains the issue of
> closing it
> somewhere.
>
> I haven't tried the cleanupAfterRequest() of Engine approach.
> Instead i've always extended the
> pageEndRender(PageEvent event)
> in a BasePage (that all my pages extend) and there I just do:
>
> super.pageEndRender(event);
> HibernateUtil.closeSession();
>
> The nice thing is that this closeSession() never complains, no
> matter
> if no session is found, or if it has already been closed.
>
> Anyway, I can post the HibernateUtil class here if you want to...
> Andreas
>
> Alejandro Scandroli wrote:
>
> >Henry Chen wrote:
> >
> >
> >>I have been searching around desperately for solution of handling
> >>lazy-loading database objects in tapestry. I configured
> >>OpenSessionInViewFilter for Tapestry pages. It worked for some
> cases
> >>but not all. For example, in the table component, the first page
> was
> >>good, but when I selected other pages, it gave me the
> >>LazyInitialization exception - owning session was closed. Is there
> any
> >>way around it now? Thanks a lot!
> >>
> >>
> >
> >Hi , I'm having the same problem on Trails.
> >This quote may help.
> >
> >quote form Open Session in View discussion on Hibernate site.
> ><quote>
> >Open Session pattern and Tapestry web framework
> >24 Mar 2004, 19:27 wassup
> >
> >If you develop your application with Tapestry framework it is
> better
> >do not use Servlet Filters to manage request cycle. More preferable
> to
> >override setupForRequest() and cleanupAfterRequest() of Engine
> >class.
> ></quote>
> >
> >I have no time to try this.
> >Please let me know if it works for you, or if you find another
> workaround.
> >
> >Saludos.
> >Alejandro.
> >
> >PD:- please, excuse my English.
> >
> >
> >
> >---------------------------------------------------------------------
> >To unsubscribe, e-mail:
> tapestry-user-unsubscribe@jakarta.apache.org
> >For additional commands, e-mail:
> tapestry-user-help@jakarta.apache.org
> >
> >
> >
> >
>
>
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Re: Hibernate+Spring: OpenSessionInViewFilter problem
Posted by Andreas Andreou <an...@di.uoa.gr>.
Regarding to not using servlet filters for the OpenSessionInView
approach, I can confirm that other approaches work!
First of all,
i've always used the HibernateUtil class posted in hibernate forums
(and maybe also included in Hibernate in Action) that stores and gets
session and transaction objects in thread local variables.
So, opening a hibernate session is never a problem (whichever method
first uses one, creates it) and so it only remains the issue of closing it
somewhere.
I haven't tried the cleanupAfterRequest() of Engine approach.
Instead i've always extended the
pageEndRender(PageEvent event)
in a BasePage (that all my pages extend) and there I just do:
super.pageEndRender(event);
HibernateUtil.closeSession();
The nice thing is that this closeSession() never complains, no matter
if no session is found, or if it has already been closed.
Anyway, I can post the HibernateUtil class here if you want to...
Andreas
Alejandro Scandroli wrote:
>Henry Chen wrote:
>
>
>>I have been searching around desperately for solution of handling
>>lazy-loading database objects in tapestry. I configured
>>OpenSessionInViewFilter for Tapestry pages. It worked for some cases
>>but not all. For example, in the table component, the first page was
>>good, but when I selected other pages, it gave me the
>>LazyInitialization exception - owning session was closed. Is there any
>>way around it now? Thanks a lot!
>>
>>
>
>Hi , I'm having the same problem on Trails.
>This quote may help.
>
>quote form Open Session in View discussion on Hibernate site.
><quote>
>Open Session pattern and Tapestry web framework
>24 Mar 2004, 19:27 wassup
>
>If you develop your application with Tapestry framework it is better
>do not use Servlet Filters to manage request cycle. More preferable to
>override setupForRequest() and cleanupAfterRequest() of Engine
>class.
></quote>
>
>I have no time to try this.
>Please let me know if it works for you, or if you find another workaround.
>
>Saludos.
>Alejandro.
>
>PD:- please, excuse my English.
>
>
>
>---------------------------------------------------------------------
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>
>
>
>
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Re: Hibernate+Spring: OpenSessionInViewFilter problem
Posted by Alejandro Scandroli <al...@gmail.com>.
Henry Chen wrote:
> I have been searching around desperately for solution of handling
> lazy-loading database objects in tapestry. I configured
> OpenSessionInViewFilter for Tapestry pages. It worked for some cases
> but not all. For example, in the table component, the first page was
> good, but when I selected other pages, it gave me the
> LazyInitialization exception - owning session was closed. Is there any
> way around it now? Thanks a lot!
Hi , I'm having the same problem on Trails.
This quote may help.
quote form Open Session in View discussion on Hibernate site.
<quote>
Open Session pattern and Tapestry web framework
24 Mar 2004, 19:27 wassup
If you develop your application with Tapestry framework it is better
do not use Servlet Filters to manage request cycle. More preferable to
override setupForRequest() and cleanupAfterRequest() of Engine
class.
</quote>
I have no time to try this.
Please let me know if it works for you, or if you find another workaround.
Saludos.
Alejandro.
PD:- please, excuse my English.
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