OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help

sca-bpel message

[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]

Subject: RE: [sca-bpel] Component Types in SCA

I had a similar reaction way back when I tried to get my head around the SCA Assembly model for the first time. Later, I settled with the following mental model:
A ComponentType defines the type of an implementation (and not that of a component as such). The association between a ComponentType and an implementation artifact is made via their collocation in a contribution or via an explicit linkage (such as by the <implementation.bpel process="xs:QName"> element in a ComponentType definition for a BPEL process) or implicitly by some derivation rules, etc. Nevertheless, a ComponentType describes an implementation, in particular, it declares the configurable elements of an implementation.
A Component on the other hand is a specific configuration of an implementation. Of course the contents of a Component would be constrained (shall we forget about the ConstrainingType for a moment!) by the ComponenType of the implementation it is configuring. But a Component is primarily anchored to the implementation in this model.
I guess the above model is different from the other examples you quote below as follows:
SCA model has three concepts related to each other - Implementation, ComponentType and Component
XML Schema, etc, on the other hand use the model of just two concepts-- a type and an instance of that type.
Just my 2c. I am sure there are other better ways to clarify this confusion ...
-- Sanjay

From: Najeeb Andrabi [mailto:nandrabi@tibco.com]
Sent: Tuesday, Feb 12, 2008 12:12 PM
To: sca-bpel@lists.oasis-open.org
Subject: [sca-bpel] Component Types in SCA


       I would like to make a comment about Component Types in SCA. This is in context with defining a component type file for BPEL implementations. I am curious about the fact that a component cannot refer a component type: it has to infer what its type might be using implementation.* element. I don’t understand the rationale behind this approach. Component type defines the type of component so why it cannot refer it. Approach of referring ones type is used everywhere in specifications like XML schema, WSDL, BPEL etc. e.g. a schema element can have a reference to complex type that defines the type of the element.


      My comment may be because of lack of understanding of SCA assembly specification. But, from my understanding of the specification I think we should allow components to refer their type.



[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index] | [List Home]