EOF objects and NON NULL validation

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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

GPG Key ID: 9CBB58FB
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