Before dropping OpenSessionInviewFilter I'd suggest to have a more thorough
look at how hibernate works. e.g. have a look at the different cascade
styles hibernate offers and also at transaction management, then it's easy
to know why, and when, hibernate "commits" without explicitly calling save
... but that's no wicket topic after all. I'm using opensessioninviewfilter
with loadabledetachablemodels in my webapp and never had problems ...
just my two cents,
Michael
thiebal wrote:
>
> I had lots of problems with a Spring MVC webapp that was using
> OpenSessionInViewFilter : beans were associated directly in DB when they
> were added to a collection (like the current Foo/Bar case) even if I
> didn't
> commit explicitly.
> Without the session opened, I can prepare all my entities and just save
> them
> and commit.
>
> I use this filter on another webapp that just load entities form DB but
> does
> not update them. It works perfectly!
>
> I though I would have the same kind of errors with Wicket because this is
> not a Wicket part but just a Hibernate functionality.
>
> If in my case, I use the filter, the Bar.foos association will be loaded
> just on demand but if I add it a new created Foo entity (transient), it
> will
> try to save it on flush (so before my save/commit) and I will have an
> exception.
> Maybe I'm wrong but I remember this kind of errors with Spring MVC...
>
> Cedric
>
>
> On Tue, Sep 16, 2008 at 10:16 AM, James Carman
> <[EMAIL PROTECTED]>wrote:
>
>> What problems does it cause?
>>
>> On Tue, Sep 16, 2008 at 9:14 AM, Cédric Thiébault
>> <[EMAIL PROTECTED]> wrote:
>> > Thanks Michael.
>> >
>> > But I don't use the OpenSessionInviewFilter and I don't want to use it.
>> > It creates more problems than it solves in my edit pages.
>> >
>> > The LoadableDetachableModel will load the whole list of choices, not
>> > just the one that was selected by the user.
>> > I will encounter the same error except if the
>> > LoadableDetachableModel.load method pre-fetch the associations...
>> >
>> > Cedric
>> >
>> >
>> > On Tue, Sep 16, 2008 at 3:01 AM, Michael Sparer <[EMAIL PROTECTED]>
>> wrote:
>> >>
>> >> Use LoadableDetachableModels (and be sure that the
>> OpensessionInviewFilter
>> >> goes before the wicketfilter) and your hibernate entity will always be
>> in
>> >> the right session
>> >>
>> >> regards,
>> >> Michael
>> >>
>> >> thiebal wrote:
>> >>>
>> >>> My DropDownChoice contains a list of hibernate entities that are not
>> >>> fully loaded.
>> >>> But when I select a value in the dropdown I receive a
>> >>> LazyLoadingException because Wicket tries to add an entry in a
>> >>> collection that was not previously loaded.
>> >>>
>> >>> I tried to use a Converter but it is not called because
>> >>> PropertyResolverConverter set directly the value (because their
>> >>> classes are compatible) :
>> >>> if (clz.isAssignableFrom(object.getClass())) {
>> >>> return object;
>> >>> }
>> >>>
>> >>> It works if I preload each entry in the list of choices of the
>> >>> DropDownChoice but it is very expensive. To display the dropdown, I
>> >>> just need to retrieve the name of my hibernate entity, not the
>> >>> collection inside this bean.
>> >>> I would like to load the collection only when the user select an
>> >>> option in the select.
>> >>>
>> >>> Code :
>> >>> class Foo {
>> >>> Bar bar;
>> >>>
>> >>> void setBar(Bar bar) {
>> >>> this.bar = bar;
>> >>> bar.getFoos().add(this); // this will throw a
>> >>> LazyLoadingException if I don't fetch the collections before I render
>> >>> the DropDownChoice
>> >>> }
>> >>> }
>> >>>
>> >>> class Bar {
>> >>> Collection<Foo> foos;
>> >>> }
>> >>>
>> >>> Is there a nice way to do that ?
>> >>>
>> >>> Thanks in advance :-)
>> >>>
>> >>> Cedric
>> >>>
>> >>> ---------------------------------------------------------------------
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>> >>>
>> >>>
>> >>>
>> >>
>> >>
>> >> -----
>> >> Michael Sparer
>> >> http://talk-on-tech.blogspot.com
>> >> --
>> >> View this message in context:
>> http://www.nabble.com/DropDownChoice-and-lazy-loaded-choices-tp19501118p19506463.html
>> >> Sent from the Wicket - User mailing list archive at Nabble.com.
>> >>
>> >>
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>> >>
>> >>
>> >
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>> >
>> >
>>
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>>
>
>
-----
Michael Sparer
http://talk-on-tech.blogspot.com
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