a) interface ierrorlistener { void error(string msg); }
b) abstract class errorreportingdataprovier implements idataprovider {
private component owner; // setter
protected abstract internaliterator(int s, int c);
protected abstract void reporterror(ierrorlistener l, exception e);
public iterator iterator(int s,int c) {
try { internaliterator(s,c); }
catch (exception e) {
ierrorlistener l=owner.findancestor(ierrorlistener.class);
reporterror(l,e);
return new emptyiterator();
}
}
c) let your dataprovider extend the one in (b)
d) make sure whatever it is you use to render the message renders
after the dataview.
-igor
On Wed, Sep 17, 2008 at 4:54 PM, mfs <[EMAIL PROTECTED]> wrote:
>
> Hello Guys,
>
> I am trying to do something similar where i have a DataView (contained in a
> webmarkupContainer) which shows the results of a search. The whole
> implementation is ajax-based. Attached to the DataView is an IDataprovider
> implementation which is responsible for fetching the data from the database.
>
> Now i want to add this very feature, where in case of any Exception/Error in
> the back-end processing (which is invoked by the DataProvider) of the
> search, I would want to add a feedback message on the same search-page,
> without being taken to the internal-error-page. As suggested I can certainly
> return an empty-list (from the IDataProvider.iterator()) or size=0 (from the
> IDataProvider.size()) method which would still render the DataView
> component, but i am not sure how to tranform or in other words transfer the
> knowledge of this Exception to the Page itself.
>
> One ugly hack could be to pass on the FeedbackMessage Label component to the
> IDataProvider which based on the success/failure is populated with right
> message, and re-render the feedback-panel on every ajax-response, but that
> looks ugly, i dont want to couple the UI response to DataProvider which
> ideally should work independently of it.
>
> Please suggest..
>
> Thanks and Regards,
>
> Farhan.
>
> i want to display a feedback message in case there is an error at the
>
> Eelco Hillenius wrote:
>>
>>> The basic question was more if I have understood the requirement to
>>> always add a component if the HTML-template named one.
>>
>> Yes.
>>
>>> If so, if there
>>> was some pattern that had evolved for handling alternate or
>>> error-flows when building the component graph.
>>
>> Alternative flows can be handled using panels or fragments possibly
>> combined with component replacements.
>>
>> As for the error-flow, and I don't really see why:
>>
>> try {
>> ...query the database and build the provider and dataview
>> } catch (SQLException e) {
>> feedback.error("Very bad things happened");
>> // What to do here??
>> }
>>
>> should generate a different component structure rather than an error page.
>>
>> Eelco
>>
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>>
>
> --
> View this message in context:
> http://www.nabble.com/newbie%3A-best-practice-for-not-rendering-component--tp12070364p19543530.html
> Sent from the Wicket - User mailing list archive at Nabble.com.
>
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