Re: EOF objects and NON NULL validation

You kind of on the wrong track.  Try reading this:
http://www.stepwise.com/Articles/Technical/2001-06-13.01.html

Chuck


At 07:20 PM 06/11/2003 +0100, Serge Cohen wrote:
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>Hello List;
>
>I'm developing a Web-Application, using WebObject and EOF together.
>In my data model, one of the attributes (lets call it Label, for the  
>entity Foo) should never be empty, so in EOModeler I've set the  
>attribute so that it does not allow nulls.
>
>I have a web form to generates Foo entities, and there is a WOTextField  
>used to get the content of 'Label'.
>If the user let the Label text field empty, I get an exception thrown,  
>because foo.label is not allowed to be null. This is normal; that's  
>what I expect from a non null attribute, but I'd like to get a bit of  
>control over, so that I can take my own action in such a case.
>
>Reading the manual, I've found (not too hard), that each class can have  
>validateKey methods, used to validate attributes BEFORE they are set,  
>seems what I was looking for...
>
>I have written a validateLabel method for the Foo class. I've checked  
>that this method is called anytime before the setLabel method is  
>called, and it's fine... EXCEPT when the value to which Label is set is  
>null... To be exact, if the textfield is directly connected to the  
>aFoo.label path, then the 'aFoo.setLabel(value)' is not called, still I  
>get an exception thrown that the Label can not be null.
>
>To be even more sure, I added a couple of println statement in my  
>validateLabel() and setLabel() method:
>- - -When the value is not null, I see that validateLabel() is first  
>called, then it exits, then setLabel() is called and exits.
>- - -When the value is null, I see that the exception is thrown BEFORE  
>any of this line are printed : these methods (validateLabel, setLabel)  
>does not even have the chance to modify the value for it to be non  
>null...
>
> From the stack trace I can see that the exception is raised in:
>	at  
>com.webobjects.eoaccess.EOAttribute.validateValue(EOAttribute.java:2315)
>	at  
>com.webobjects.eoaccess.EOEntityClassDescription.validateValueForKey(EOE 
>ntityClassDescription.java:439)
>	at  
>com.webobjects.eocontrol.EOCustomObject.validateValueForKey(EOCustomObje 
>ct.java:1332)
>
>EOCustomObject from which my object inherit (through EOGenericRecord).
>
>Is there anyway to avoid having to override  
>EOCustomObject.validateValueForKey, still have the validateLabel called  
>before the generic validateValue method (the one checking it's not  
>null)? I have the feeling it can be quiet tricky to override this  
>method and avoiding getting things wrong... I've not found any  
>doc/example about overriding this method.
>
>
>I've searched the doc to get a better grasp of the validation/setting  
>cycle after a user submit a form, but I've found no precise description.
>
>
>Thanks for any tips, info, or pointer to resources!!
>(it's also likely that I've been too far in the analysis... and that I  
>just missed the simple+proper solution!!)
>
>Serge.
>
>- ----------------------------------------------------
>Serge Cohen
>
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