Good SOA reading - book by Chris Kurt, Louis Felipe Cabrera

[Duane Nickull <dnickull@adobe.com>]

TC:

I am reading a new book by Chris Kurt et al called "Web Services 
Architecture and its' specifications", Microsoft Press.  While it is 
concrete, some of the text is highly relevant to us.  I would highly 
recommend the book based on my reading so far. 

Here are some key excerpts:

"... Service orientation is an abstract set of ideas and concepts that 
can be manifested in a number of ways....Web services can be used to 
implement a SOA system, but service orientation does not necessitate the 
use of web service protocols, nor does the use of web service protocols 
ensure that the overall system design is SOA".

This validates our positioning and is how the TC founders viewed the 
relationship.  He did a much better job of eloquently stating it however ;-)

There is a discussion that relates to the "Data Model" on the MNPP.  
While in the book it refers to the concrete XML Infoset, the definition 
is interesting and highly relevant:

"The (data model concept of RM) models ... a set of information items."  
Paraphrasing this to equate it to the abstract concept of data model, 
which includes the building blocks for conceptual parameter exchanges, 
might be a good definition.

Chapter 3 also starts discussing some more advanced concepts of the 
metadata in WSA.  Chris used the term "contract" in roughly the 
equivalent way we have.  

"Contracts are the central concept to express the capabilities and 
deployment constraints of services ... as well as the abstract 
capabilities of the service".  While we do not care about the concrete 
deployment constraints, we do abstract the concept.  Perhaps we can 
abstract this definition with ours.

Contracts are expressed using different types of metadata.  The closest 
translation to our RM would be the data model and the policy 
(capabilities and requirements).  Policy is interesting because it can 
also include the notions of constraints on how a service may be consumed 
(perhaps a flag for security).

The core concepts of services being autonomous and opaque are also 
embraced in this book.

Duane

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Senior Standards Strategist - Adobe Systems, Inc. - http://www.adobe.com
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