RE: Contradictions regarding transitivity of wsdl:import

I didn't think this was where we ended up after my 'illumination'
e-mail... What happened? 

Gudge

> -----Original Message-----
> From: David Booth [mailto:dbooth@w3.org] 
> Sent: Monday, April 18, 2005 6:53 PM
> To: Arthur Ryman
> Cc: Martin Gudgin; www-ws-desc@w3.org
> Subject: RE: Contradictions regarding transitivity of wsdl:import
> 
> On Mon, 2005-04-18 at 12:17, Arthur Ryman wrote:
> > David,
> > 
> > I don't think this works in general. The reason is that documents
> > refer to each other so there really isn't a component model for each
> > document..
> 
> I now understand that that is the current design of the component
> model.  I was suggesting that instead there should be a 
> component model
> for each WSDL 2.0 document (i.e., each wsdl:description element
> information item), along the lines of option 2 that you propose below.
> 
> > 
> > You could have a document that didn't refer to any other 
> document, and
> > that would have a component model. That is a "leaf" node.
> > 
> > Document can actually have circular references to 
> eachother. The spec
> > permits this. The component model therefore must include all the
> > components in order to satisfy the intercomponent references.
> > 
> > My reading of the spec is that all components belong to a single
> > instance of the component model. The instance is defined by a root
> > document and the set of documents it references.
> > 
> > There are two possible ways we could improve the clarity of 
> the spec:
> > 
> > Option 1. Rename the Description Component to the Component Model
> > 
> > This actually eliminates the Description component altogether and
> > replaces it with an object called the Component Model. The 
> spec talks
> > a lot about the component model, but never actually defines 
> it. We can
> > make it clear that the component model contains all the components
> > from all the documents processed.
> > 
> > Option 2. Define the Component Model to be a set of Description
> > Components, and restrict each Description component to only contain
> > the components defined in it
> 
> Yes, I think this approach would be a considerably clearer and more
> straightforward way to go.  However, I would nitpick about the word
> "set".  "Directed graph" would be more precise:  A given WSDL 2.0
> document would have a single Description component, which may refer to
> other Description components (if the original WSDL 2.0 
> document imports
> other documents, for example), thus representing a directed graph.
> 
> > 
> > This makes the mapping between Description components and documents
> > clearer. 
> 
> Yes, and we need people to understand our spec.  We have already
> received complaints about how hard it is to understand.   
> 
> > It introduces the technical subtlety of what to do about duplicated
> > components. We currently allow duplicate components to come from
> > different documents as long as the components are equivalent. To
> > resolve component references, we need to pick a particular component
> > among the set of equivant components (or formally introduce 
> the notion
> > of equivalence class and make component references resolve 
> to those).
> 
> I think we have that subtlety already, but you're right it 
> will have to
> be resolved differently.  There are several ways it could be 
> handled.  I
> doubt equivalence classes would be needed.  One way is for each
> Description component to have an {imported descriptions} 
> property.  Then
> if a new document is imported, ignore it if its corresponding
> Description component is already in that set.
> 
> 
> -- 
> David Booth <dbooth@w3.org>
> 
>

Received on Tuesday, 19 April 2005 01:56:21 UTC