Re: Validation and Events

George Lee wrote:
>> Also - I don't remember whether notify() blocks until all event handlers 
>> have completed or not. Presuming it does, that approach could work.
> 
> Sorry, can you clarify what you mean here, and what the possible pitfall is?

So:

class IArchetypesValidationEvent(Interface):
     object = Attribute('The object being validated')
     errors = Attribute('The errors dict')

class ArchetypesValidationEvent(object):
     implements(IArchetypesValidationEvent)
     def __init__(self, object, errors):
         self.object = object
         self.errors = errors

def validateMyObject(evt):
     if evt.object.foo == bar:
         evt.errors['foo'] = "Don't do that"

Now, we'd do:

def post_validate(self, errors):
     ...
     # Let other validators do their magic
     notify(ArchetypesValidationEvent(self, errors))

     # Did they do anything?
     if len(errors) > 0:
         return False # we have an error

This is pseudo-code, obviously. But the point is, if notify() didn't 
block until all event handlers were finished, then you couldn't check 
the 'errors' dict like that!

> I smell a test to write.

Go ahead :)

> Well actually, are there ideas on how to write a test for this validation event?
> It feels complicated.

Something like the above - an event with a handler that mutates 
something so that you can check whether the mutation has happened by the 
time you reach the code after the call to notify(). Or just trace 
notify(). I think it blocks, I'm just not 100% sure.

If you can dig into AT and determine where best to fire this event, we 
may try to get this done.

Martin


-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys -- and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV