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Date: Mon, 14 Mar 2005 15:48:44 +0100
From: Sylvain Wallez <sylvain@apache.org>
Organization: Anyware Technologies
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To: dev@cocoon.apache.org
Subject: Re: [cForms] Errors coming from service layer
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 <42359CD3.1020209@apache.org>
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Reinhard Poetz wrote:

> Vilya Harvey wrote:
>
>> Reinhard P�tz wrote:
>>
>>>
>>> Imagine following scenario: You have a service layer that is exposed 
>>> as web services. cForms already does as much validation as possible 
>>> but some complex checks can only be performed by the backend.
>>>
>>> If I call a webservice (via Axis client) this webservice can return 
>>> errors (how this is done hasn't been defined yet).
>>>
>>> Are there any best practices or experiences how to map errors coming 
>>> from the service or domain layer to cForms widgets? (The error has 
>>> to appear at widget level.)
>>
>>
>>
>> In your flowscript, you can create your own ValidationError object 
>> and explicitly set that on the apppropriate widget.
>>
>> What we did was to define our own type of exception which included 
>> information about all validation errors that were found, then wrote a 
>> simple(-ish) flowscript function which handled looking up the 
>> relevant widgets, creating the error objects and setting them into 
>> the widgets.
>
>
> Thank you!
>
> This means that the service layer is aware of which widgets exist? I'm 
> not sure if I (and especially my customer) likes this bi-directional 
> dependency...


Nono! Your validation code has to catch the exception and translate it 
into a validation error. This means you can have "regular" validation 
errors (i.e. the backend could be reached but detected invalid data) and 
communication-level errors, e.g. "could not validate data, try again later".

Sylvain

-- 
Sylvain Wallez                                  Anyware Technologies
http://www.apache.org/~sylvain           http://www.anyware-tech.com
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