Christophe Combelles wrote:
I think that it's not work: "alsoProvides" and "directlyProvides" change
interfaces only in memory, it's not persistent changes (after restart
Zope yours object will be only basic interface) .
Christophe Combelles a écrit :
I'm playing again with the notion of categories of objects.
I have two main goals:
1) I must let the user choose the category of an object added to the
zodb. For this, I must be able to retrieve the list of categories and
present them in a form field managed by a vocabulary (or in a
2) I must have different behaviours for categorized objects:
objects of different categories would have different views, different
addMenuItems (if they are containers), etc.
the first requirement would tell me to define categories as objects,
while the second one would tell me to define them as interfaces.
The possible solutions I see:
1) The simplest solution is to store the categories as text strings
into the annotations of the object. So categories actually are just
2) The second solution is to do the same, but replace text strings
with category objects, that implement ICategory. And categories can
be stored separately in a category container, or in a registered
utility that gives the list of available categories. This is a bit
better, but this way I don't know how to easily let my categorized
objects behave differently according to their categories.
3) The third solution is to define categories as interfaces extending
ICategory. I can retrieve the list of categories with
But to present them in a form, I must have a pretty name for each
interface. Should I store them in a Tagged Value?
4) The fourth solution I see, is to define an interface type,
ICategoryType, extending IInterface just like IContentType. Then my
categories would be interfaces whose type is ICategoryType. But with
IContentType, is there a way to retrieve the list of all available
I've finally mixed 3) and 4) :
I have defined ICompany(Interface), IClient(ICompany),
And I have an ICompanyType(IInterface) interface type
I've set the type of IClient and IProvider as ICompanyType in zcml.
ICompany has a "types" attribute, for which I've redefined __getattr__
__getattr__ retrieve the ICompanyType interfaces from the object
__setattr__ calls noLongerProvides then alsoProvides to change the
(sorry my honor english).
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