Re: [higgins-dev] Context Provider vs. Context Factory

[Greg Byrd <gbyrd@xxxxxxxx>]

My concern with using the term "factory" is that the functionality 
associated with the IContextProvider interface (in the working draft: 
http://spwiki.editme.com/files/IdentityAttributeService/idas-methods-0707.doc) 
is larger than what I generally associate with a factory.

(1) The open method evaluates the policy of the named Context against 
the supplied DigitalIdentity.  (Is this correct?  When Tom posited that 
"the Context Factory does not concern itself with the evaluation nor 
enforcement of policy," Paul agreed.)

(2) The getContexts (or getOpenContexts) method implies that a factory 
keeps track of the Contexts that it has created, or can create, or for 
which it is somehow responsible.  Most factory classes that I'm familiar 
with simply create the object and hand it over.

(3) The closeContext method again implies some further connection with 
the Context after its creation.


So I've reverted back to using ContextProvider to refer to this entity, 
because it seems like more than a factory.  The problem is that 
"provider" is a loaded term that is generally associated with 
packaging/deployment. 

I propose that we do one of the following:

(a) Keep the current assignment of duties of the current 
IContextProvider but rename it to something that conveys more than 
object creation, e.g., IContextManager.

(b) Refactor the functionality of IContextProvider into creation 
(IContextFactory), access (IContext), and management (registry) of 
contexts.  (Where does the resolution of a ContextRef to a Context 
object happen?  Factory?  Static method of Context class?)

I further propose that there is no need to include the "provider" notion 
(in the sense of packaging/deployment) in the API.  The factory/manager 
object has metadata that can be used to convey vendor, data formats, 
etc.  There will be different Registry implementations for different 
platforms, and each implementation must specify the process for 
registering and incorporating new types of factory/manager.

...Greg