RE: Definition of Choreography

> -----Original Message-----
> From: Jianhua Zhu [mailto:[email protected]]
> Sent: Sunday, October 20, 2002 4:32 PM
> To: [email protected]
> Subject: RE: Definition of Choreography
> 
> 
> are there cases where the  states of a public
> process and the states of an internal process are 
> intertwined, i.e.,needing
> to transition from a public process state to a private 
> process state and  vice versa?


I for one am using "public" to describe the contract
that a complex web service would offer to its consumers.
It would describe which messages move the overall service
from one state to another, which states are preconditions
for specific messages, and so on.  

The implementation of the complex service would presumably
all be "private" in that any language or framework could be
used to implement it so long as the overall behavior 
met the contract defined by the choreography state machine.

So, yes the *implementation* of a choreography would probably
do all sorts of stuff that involves all sorts of internal 
messages not specified in the public choreography.  For example,
imagine a public choreography that would describe for independent
insurance agents some (hypothetical) industry standard practice
for gathering the information needed to submit a claim, actually
submitting it, and dealing with the range of responses.  Something
like "PolicyVerified" might be a state, and a message "submitClaim"
might be legal once the system is in that state, and that message
could result in one of three states -- ClaimPending, ClaimAccepted,
ClaimRejected.  Now look at the link that Edwin Khodabakchian 
provided http://www.collaxa.com/maps/claim.jpg to see the immense
complexity behind the scenes at an actual recipient of a 
"submitClaim" message.   

So, I'd answer by saying that the "public process state" is merely
an abstraction of some set of variables in a private implementation
of the choreography, so it's not really helpful to think about
a transition from a public process state to a private process state.