2005/9/16, Martin Marinschek <[EMAIL PROTECTED]>:
Hmm,
but you can't restore the value if there is no DataModel you are
binding to, but just a simple list, right?
regards,
Martin
On 9/16/05, Enrique Medina < [EMAIL PROTECTED]> wrote:
> Hi Martin,
>
> What does 'ev' stands for?
>
> One of the possible solutions I suggested was, the same way a new
> _SerializedDataModel is generated from the current data model (my own
> ListOfObjectsAsListDataModel), to assign the serialized data model to the
> original data model in the restoring data phase.
>
> Please also note that I also posted a solution to the problem of lazy
> loading in Hibernate through the use of a LazyListDataModel object via
> callback mechanisms (so this will also not work with preserveDataModel...).
>
> 2005/9/16, Martin Marinschek < [EMAIL PROTECTED]>:
> > Well,
> >
> > the preserveDataModel feature was not programmed especially for this
> > use, I would say. I understand your interest for such a usecase,
> > though.
> >
> > Were I've got my problems is that with normal valueBindings for the
> > dataTable, the model of the backing bean will not be used until the
> > render response phase, instead the serialized data model will be used
> > - for me this means that you will need to use the serialized data
> > model in your backing bean as well.
> >
> > Why do you need to use your original model?
> >
> > can't you say ((UIData) ev.getParent().getParent()).getDataModel()?
> >
> > regards,
> >
> > Martin
> >
> >
> > On 9/15/05, Enrique Medina < [EMAIL PROTECTED]> wrote:
> > > Hi again,
> > >
> > > I have investigated another interesting behaviour about using
> > > PreserveDataModel, which makes my application crash (due to the way I'm
> > > working with data tables). Let me explain it to you in a
> straight-forward
> > > manner.
> > >
> > > Currently, I use a session scoped bean to work with my objects ( e.g.
> one
> > > bean to work with customer objects, one bean to work with the users,
> etc),
> > > due to the fact that I don't want to loose state between requests (yes,
> I
> > > know it could have been done using <t:saveState>...). So within all my
> > > session beans, I have defined a ListDataModel variable that holds the
> data
> > > model that is presented to the view every time the view is rendered
> (nothing
> > > strange here, I guess).
> > >
> > > From my views (JSP), I simply use:
> > >
> > > <t:dataTable ......
> > >
> value="#{ sessionScopedWhateverBean.listOfObjectsAsListDataModel}"
> > > ....>
> > >
> > > So whenever the view is rendered, the method "public DataModel
> > > getListOfObjectsAsListDataModel()" in my session scoped
> > > bean is invoked. Obviously, the first time it will be created, and the
> > > subsequent calls simply will return the existing object. Everything's
> fine
> > > here.
> > >
> > > The problem comes when using PreserveDataModel because, as explained in
> the
> > > wiki I posted about working with PreserveDataModel, every object in my
> > > listOfObjectsAsListDataModel is added to a new ArrayList belonging to a
> new
> > > _SerializedDataModel object, which is the object being really serialized
> > > when saving the state by the JspStateManagerImpl. And why is it the
> problem?
> > > Think about the future restoring phase...
> > >
> > > When a link is clicked inside the data table to work with a particular
> > > object, the event created as a consequence of the "clicked link" has the
> > > information about the exact row which has been clicked (specifically in
> its
> > > rowIndex attribute). Following, the state is restored, and the
> previously
> > > serialized data model (as a _SerializedDataModel object) is used to set
> the
> > > information about the "clicked row". What does this mean? It's as simple
> as
> > > this: the "clicked row" information is set on the restored object, so it
> is
> > > really set on the _SerializedDataModel object (nothing to be with our
> > > original ListOfObjectsAsListDataModel object).
> > >
> > > When afterwards the broadcast calls our action method (the one
> associated
> > > with the link in the data table through usually an HtmlCommandLink tag),
> our
> > > session scoped bean has the original ListOfObjectsAsListDataModel object
> > > that was used to create the _SerializedDataModel object when saving the
> > > state. But with a definitive difference: the rowIndex from the event was
> set
> > > on the _SerializedDataModel object, not the one we have here now, i.e.
> our
> > > ListOfObjectsAsListDataModel object. And due to the fact that our
> > > ListOfObjectsAsListDataModel was used to create the _SerializedDataModel
> > > object, now it has its internal rowIndex attribute set to the last row
> plus
> > > one (obviously, as the saveState method iterates through the
> > > ListOfObjectsAsListDataModel list of objects to populate the
> > > _SerializedDataModel list of objects).
> > >
> > > At the end, the result is a call to setRowIndex(last row + 1), which
> > > obviously does not exist, so a "IllegalArgumentException: row is
> > > unavailable" is thrown. On the other hand, if I don't use
> preserveDataModel,
> > > everything works perfectly, as the ListOfObjectsAsListDataModel object
> is
> > > the one used to save the state (not the _SerializedDataModel).
> > >
> > > IMHO, the solution will be as simple as updating my
> > > ListOfObjectsAsListDataModel object with the _SerializedDataModel object
> > > when restoring the state. But I would like to hear the MyFaces' team
> experts
> > > about this possibility before going deeper into the code.
> > >
> > > Is it feasible? Is it possible to work with the preserveDataModel
> together
> > > with a DataModel inside my bean and the getRowData() method? Is the use
> od
> > > preserveDataModel incompatible with using the getRowData() method inside
> my
> > > bean?
> > >
> > > Looking forward to hearing your comments :-)
> > >
> >
> >
> > --
> >
> > http://www.irian.at
> > Your JSF powerhouse -
> > JSF Trainings in English and German
> >
>
>
--
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