[Zope] inheritedAttribute doesn't seem to work

28 Jul 2003

      inheritedAttribute does not seem to work for me.  The situation is 
summarized as follows

I have the following module in a the std python path

/usr/local/lib/python/site-packages/PackageA/ModuleA

ModuleA defines 20 different classes, and factory methods to generate 
instances of these.

In a zope product in zope/lib/python/Products/MyProduct  I have the 
following in MyProduct.py

from PackageA import ModuleA

class MyProduct( Folder.Folder, Persistent, Implicit ):

    blah ( manage options, security, metatype etc)

    def __init__(self, id, title, name ):
        self.id = id
        self.title = title
        self.name = name
        self.dataModels = []

    def addModel( self, textData ):
        """Add some data"""
        self.dataModels.append( Data( textData ) )
        self._p_changed = 1

class Data:

    blah (security)

    def __init__( self, dataText ):

        self.dataModel = ModuleA.generateModel( dataText )  

the generateModel( dataText ) is a text parser, and factory locator and 
caller. 

To get secirty settings into the 20 or so Classes in ModuleA I needed to 
proxy them in the product here. The model that is generated is basically 
a directed acyclic graph, with one top node, which is an object of type 
Model.  The proxy object for model looks like the following

class ModelProxy( ModuleA.model ):

    blah( security settings)

    def __init__( self, attributeDict, parentObject ):

        ModuleA.model.__init__( self, attributeDict, parentObject )
        # attributeDict, parentObject are simply attributed that are 
passed by the text parser
        # to construct in this case a Model object

This all works fine, and I end up with happily constructed models in the 
dataModels attribute of MyProduct with all nodes of the graph accessable 
to python scripts.  But then I decided that since I opened up these 
models to be accessed through python scripting, i.e. the reason for the 
security proxy objects in the first place, then I should clean up the 
persistence parts so that changes to the model objects are persisted.

I thought adding Persistent into the proxy objects for the 20 different 
kinds of classes would be sufficient, and of course ran into the "Error 
Value: unbound method __init__() must be called with instance as first 
argument" problem.

To solve this I tried the following replacement for ModelProxy (and 
similarly for all the others)

class ModelProxy( Persistent, ModuleA.model ):

    blah( security settings)

    def __init__( self, attributeDict, parentObject ):

        Persistent.inheritedAttribute('__init__')( self, attributeDict, 
parentObject )

but still got the error.

I even tried

class ModelProxy( Persistent, ModuleA.model ):

    blah( security settings)

    _model__init__ = ModuleA.model.__init__

    def __init__( self, attributeDict, parentObject ):

        ModelProxy._model__init__( self, attributeDict, parentObject )  
        # or self._model__init__( attributeDict, parentObject )

and still got the same error.

Does anyone have any ideas what may be wrong?

I am also interested whether simply making the different objects(which 
are nodes in the DAG) persistent is enough to signal all the way back up 
MyProduct that self.dataModel has changed when one of the nodes deep in 
the graph has changed.

regards
Matt