W3C home > Mailing lists > Public > public-ws-chor@w3.org > April 2003

RE: Feedback on Glossary

From: Cummins, Fred A <fred.cummins@eds.com>
Date: Tue, 22 Apr 2003 21:40:53 -0500
Message-ID: <27C20ED5A6D3D511ADF30002A5D6464802C02CD6@USPLM214>
To: Assaf Arkin <arkin@intalio.com>
Cc: "Monica J. Martin" <monica.martin@sun.com>, public-ws-chor@w3.org


I agree with your final statement--rely on the dictionary.

Regarding application to choreography, you should allow that
the "parts" may be choreographies or something more primitive.


> -----Original Message-----
> From: Assaf Arkin [mailto:arkin@intalio.com]
> Sent: Tuesday, April 22, 2003 10:29 PM
> To: Cummins, Fred A
> Cc: Monica J. Martin; public-ws-chor@w3.org
> Subject: Re: Feedback on Glossary
> Cummins, Fred A wrote:
> >Monica,
> >
> >Feedback on the glossary,
> >
> >Composition.  [This definition is becomeing much too 
> complicated.  How
> >composition is addressed in choreography is to be defined by 
> the final
> >specification.  What we mean 
> >by composition should be quite simple: creation of a unit or 
> product from
> >components or parts.  There is an implication that the 
> components or parts
> >may be used to compose a variety of units or products.  To 
> extend this to
> >choreography, composition is the creation of a choreography 
> from parts that
> >may be used to create a variety of choreographies.]
> >  
> >
> The term composition is very generic and I wanted to point 
> out that it 
> can be used for many different things. Let's say that I have 
> two states, 
> one in which I accept an order and one in which I send a shipping 
> notice, and a transition between the two. The combination of 
> all three 
> is a composition.
> I found it very helpful to use the term composition in many different 
> places. For example, a process definition is a heirarchical 
> composition 
> of activities. But since a process can use other processes as 
> well, it's 
> also a recursive composition. A global model is defined easily as a 
> composition of interfaces/service types that are linked to 
> each other. 
> The idea is that you can decompose these interfaces/service types and 
> then recompose them into other choreographies (reuse).
> While composition is a very generic term (X+Y=Z), and so is recursive 
> composition (X(a)+X(b)=X(c), there are more specific types of 
> compositions that we are interested in. I think we need to spell them 
> out and properly qualify them.
> For example, a recursive service composition is a composition of 
> services (be it a choreography, orchestration or just a 
> shopping list) 
> that results in a new service. A recursive choreography 
> composition is 
> the ability to take multiple choreographies and compose them into a 
> larger choreography. A choreography itself is a composition 
> but it may 
> not be recursive, it may be the composition of elements of 
> other types 
> (e.g. interfaces, services, message types, etc).
> I definitely agree with your definition:
> To extend this to choreography, composition is the creation 
> of a choreography from parts that
> may be used to create a variety of choreographies.
> My friendly amendment would be to rephrase it as:
> A choreography is a composition created from parts that may 
> be used to create a variety of choreographies.
> But I think that the definition of composition by itself 
> should either 
> be generic to allow for any other types of compositions we care about 
> (now and in the future), or that we can just rely on the dictionary 
> definition but define specific qualified types of 
> compositions we care 
> about in the glossary.
> arkin
Received on Tuesday, 22 April 2003 22:41:01 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 19:30:01 UTC