Yes, but am not very advanced in jsf life cycle and such things. I
understood there a web page is a snapshot, but i wonder how to update
model if you have to constatly keep in ,ind that in fact your model must
not change? How do i plug something in somewhere to have make this
refresh at a moment that won't alter the behaviour of datatable?
Mike Kienenberger a écrit :
> A datatable's model is not the same as the database state.
>
> The model needs to remain constant from one renderResponse to the next
> invokeAction. If the rows don't match between the two requests, then
> it's meaningless to have any UICommand or UIInput components in the
> dataTable since there's no way to get from the generated-html "view"
> of the data from the previous request to the backing objects that
> created that view.
>
> It's up to your application to determine if the database still matches
> the model when parsing the next requests. And after handling that,
> right before every renderResponse, you should feel free to refetch the
> database state into the model so it's up-to-date again.
>
> A database changes constantly. But web pages are snapshots at
> discrete intervals into that database.
>
>
> On 9/18/06, delbd <[EMAIL PROTECTED]> wrote:
>> It's a database, values always change and not only during an action.
>> That's why i am using request scope bean for those values, which brings
>> me troubles when it comes to needing a permanent state for datatable to
>> work properly...
>>
>> Mike Kienenberger a écrit :
>> > You only need to reset the bean values if the bean values change in
>> > some way beyond the normal flow of the program. Ie, if you click on
>> > a button, and suddenly a row is gone, then you need to reset your
>> > cached/saveState'd backing list.
>> >
>> > If you have a specific example, I can offer you some specific advice.
>> >
>> > On 9/18/06, David Delbecq <[EMAIL PROTECTED]> wrote:
>> >> Ok, In this case that can be applied because this action is the
>> only one
>> >> involved in that specific form. But what about more complex form,
>> where
>> >> there is such a table but lots of possible actions, if i need to
>> always
>> >> reset the bean value between the decode and the encode operations?
>> >> Mike Kienenberger a écrit :
>> >> > Yes to both of you. All you need to do is update your backing
>> data
>> >> > model in the action -- pretty convenient :-)
>> >> >
>> >> > Ie, if you have something like
>> >> >
>> >> > <h:dataTable value="#{sharkEngine.acceptedAssignments}"
>> >> > <h:commandLink action="#{sharkEngine.action.showActivity}"
>> >> >
>> >> > then in #{sharkEngine.action.showActivity} you change the value of
>> >> > sharkEngine.acceptedAssignments to be the updated list.
>> >> >
>> >> >
>> >> > On 9/16/06, delbd <[EMAIL PROTECTED]> wrote:
>> >> >> So then my problem is how to have the datatable contains old datas
>> >> >> before action and new datas after action...
>> >> >
>> >> > On 9/16/06, Mr Arvind Pandey <[EMAIL PROTECTED]> wrote:
>> >> >> u r right. u can use preserveDataModel="true" in
>> >> >> datatable. if it is true then action method surely be
>> >> >> invoked. But the problem is if u want to delete the
>> >> >> row from table and afetr deletion you want to display
>> >> >> the same page then row will be deleted from DB but
>> >> >> page will contain that row. I am looking for the soln.
>> >> >
>> >> >> Mike Kienenberger a écrit :
>> >> >> > h:dataTable value="#{sharkEngine.acceptedAssignments}" must
>> remain
>> >> >> > constant from renderResponse of the first request through
>> >> >> > invokeAction of the second request.
>> >> >> >
>> >> >> > I handle this by using <t:saveState
>> >> >> > value="#{sharkEngine.acceptedAssignments}">
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> > On 9/15/06, David Delbecq <[EMAIL PROTECTED]> wrote:
>> >> >> >> Hello,
>> >> >> >>
>> >> >> >> I have a datatable that iterate over some database values.
>> Those
>> >> >> values
>> >> >> >> are subject to change, especially in quantity. The datatable is
>> >> >> rendered
>> >> >> >> like this:
>> >> >> >> <h:dataTable value="#{sharkEngine.acceptedAssignments}"
>> >> >> >> var="theAssignment">
>> >> >> >> <h:column>
>> >> >> >> <h:commandLink immediate="true"
>> >> >> >> value="#{theAssignment.activity.name}"
>> >> >> >> action="#{sharkEngine.action.showActivity}"
>> >> >> >> actionListener="#{sharkEngine.action.commandListener}">
>> >> >> >> <f:param name="activityToShow"
>> >> >> >> value="#{theAssignment.activity.key}" />
>> >> >> >> </h:commandLink>
>> >> >> >> </h:column>
>> >> >> >> </h:dataTable>
>> >> >> >>
>> >> >> >> This basically renders a list of links that need to contain one
>> >> >> >> information: "activityToShow". Technically,
>> >> >> >> #{sharkEngine.action.showActivity} will need nothing more to
>> setup
>> >> >> >> session and show the edition form. However, between display of
>> >> >> table and
>> >> >> >> click by user, the database list referenced by datatable is
>> >> >> subject to
>> >> >> >> change (because whatever happens, we must reflect db
>> changes to
>> >> >> user).
>> >> >> >>
>> >> >> >> Here is the problem:
>> >> >> >> If 3 items are showned to user (let's say a,b,c), the user
>> clicks
>> >> >> on the
>> >> >> >> last one (c) but by that time the entry a has been removed from
>> >> >> >> database, the action does not take place?!?
>> >> >> >> I suspect this is because the 3rd line of datatable has been
>> >> >> removed,
>> >> >> >> but how do i handle this. The user won't accept that nothing
>> >> happens
>> >> >> >> while he clicks on an entry, obviously. JSF is silent on why it
>> >> >> did not
>> >> >> >> execute the action and <h:messages/> shows nothing too.
>> >> >> >>
>> >> >> >> What is the good way to create such list of links?
>> >> >> >>
>> >> >>
>> >> >>
>> >>
>> >>
>>
>>
