[Zope3-Users] Problem with containers

[Rob Campbell]

Martijn Pieters wrote:
> On 9/15/06, Rob Campbell <rcampbell at pcwi.net> wrote:
>> I just recently started trying out Zope 3.  My first test project is a
>> few containers that can contain other containers or an object.  They are
>> laid out as follows:
>>
>> FosterRecord
>> -> FosterSource
>>      -> Foster
>>      -> FosterGroup
>>         -> Foster
>>
>> A FosterRecord is the top level container and can contain a
>> FosterSource.  A FosterSource can contain a Foster object or a
>> FosterGroup.  And a FosterGroup can contain a Foster object.
> 
> You cannot combine multiple contained or container constraints; you'll
> have to define a contained contstraint for the Foster implementation
> that includes both IFosterSource and IFosterGroup.
> 

Ok, so it can't be done by implementing both IFosterSourceContained and 
IFosterGroupContained?  I am doing that currently with the following code:

class Foster(Contained):
 

   implements(IFoster, IFosterSourceContained, IFosterGroupContained)

Would I need to create a new IContained interface?  Maybe something like 
this:

class IFosterSourceOrGroupContained(IContained):

   containers(IFosterSourceContainer, IFosterGroupContainer)

and then change Foster to this:

class Foster(IContained):

   implements(IFoster, IFosterSourceOrGroupContained)

Thank you for the help.

--
Rob Campbell