Typically, what I have seen is to store the data in a request scoped
member variable. This is used with "if not loaded, load, otherwise use
current instance" paradigm.
There are 3 libraries that I am aware of that also provide on-load
functionality, so that you can load the data before rendering (thus
making error handling easier):
* jsf-comp on-load
* Seam
* Shale
The simplest way is to store you model directly on the request context
from the external request.
-Andrew
On 10/19/07, Martin Ahrer <[EMAIL PROTECTED]> wrote:
>
> I'm trying to implement a simple query by example view (qbe.jsp) containing
> * a form with the query criteria,
> * a table with query results
> * a form for editing a selected table row
>
> <tr:panelFormLayout rendered="#{formController.entity==null}">
> ...the query form
> <tr:inputText value="#{qbeController.example.criteria}"/>
> </tr:panelFormLayout>
>
> <tr:table value="#{qbeController.model}" var="object"
> rows="5" width="200" rendered="#{formController.entity==null}">
> ...the query result
> ...
>
> <tr:column sortable="true" headerText="criteria">
> <tr:commandLink action="#{qbeController.select}">
> <tr:outputText value="#{object.type}" />
> </tr:commandLink>
> </tr:column>
>
> </tr:table>
>
> <tr:panelFormLayout rendered="#{formController.entity!=null}">
> <tr:subform>
> ...the editor form
> ...
> </tr:subform>
> </tr:panelFormLayout>
>
> In the most simple implementation the table is populated by a getModel()
> method (#{qbeController.model}).
>
> protected DataModel model = new ListDataModel(Collections.EMPTY_LIST);
> @Override
> public DataModel getModel() {
> model.setWrappedData(service.queryByExample(example));
> return model;
> }
>
> As the page is going through the JSF lifecycle the getModel() method is
> called multiple times resulting in multiple database hits. The database hits
> are unnecessary, it should be sufficient to query the database once.
> The query should be performed after the UPDATE_MODEL_VALUES phase (i.e after
> the values from the query form have been applied to the backing bean ->
> #{qbeController.example.criteria} ). This is the earlies t phase where it
> makes sense to perform the query!
>
> So I was trying to do some optimization to avoid this. Using the JSF 1.2
> <f:view> afterPhase/beforePhase method bindings I tried to perform the
> actual database query...
>
>
> public void beforePhase(PhaseEvent event) {
> if (event.getPhaseId().equals(PhaseId.APPLY_REQUEST_VALUES)) {
> System.out.println();
> }
> System.out.println("before " + event.getPhaseId());
> if (event.getPhaseId().equals(PhaseId.RENDER_RESPONSE)) {
> if (model.getWrappedData() == Collections.EMPTY_LIST) {
> model.setWrappedData(service.queryByExample(example));
> }
> }
> }
>
> public void afterPhase(PhaseEvent event) {
> System.out.println("after " + event.getPhaseId());
> if (event.getPhaseId().equals(PhaseId.UPDATE_MODEL_VALUES)) {
> if (model.getWrappedData() == Collections.EMPTY_LIST) {
> model.setWrappedData(service.queryByExample(example));
> }
> }
> }
>
> protected DataModel model = new ListDataModel(Collections.EMPTY_LIST);
>
> @Override
> public DataModel getModel() {
> // model.setWrappedData(getCrudService().findByExample(example));
> return model;
> }
>
>
> The query result is correct! But the table dows not allow to click a row and
> call the row editor! Seems that the table is missing something if no rows
> are available during the APPLY_REQUEST_VALUES phase
>
> Ok next, I try to do the query before the APPLY_REQUEST_VALUES phase ->
> selecting a table row works but the query result is not correct as the query
> criteria has not yet been applied to the backing bean
> (#{qbeController.example.criteria}).
>
> Hmmm, interested in your ideas about this... thx
> --
> View this message in context:
> http://www.nabble.com/-trinidad--what-is-the-proper-lifecycle-phase-for-populating-a-%3Ctr%3Atable%3E-tf4654950.html#a13300085
> Sent from the MyFaces - Users mailing list archive at Nabble.com.
>
>
