Need some clarification on actions, message exchange, & operations

["Jeffrey A. Estefan" <jeffrey.a.estefan@jpl.nasa.gov>]

Frank and Team,

 

We need to resolve some of the ambiguities surrounding the following concepts and their relationships in the context of service interaction:

 

1. Actions

2. Action model

3. Operations

4. Message exchange

5. Real world effect

6. Execution context

 

Omitting item 6 for the moment, here's what I've captured during my note taking from the various telecons and discussion threads.

 

* An action is expressed or defined in terms of message exchange between participants. In other words, exchange of a message counts as performing an action.

* The action model (an element of a service description’s behavior model) describes the set of actions required to result in a real world effect. 

* The combination of the message exchange and the message content denote the action.

* The action results in an operation being performed.

* The result of an action can result in an operation on the service and the result of an operation would be the real world effect.   Consequently, the action results in an operation being performed

So, one concept that needs to be clarified based on the attached UML diagram is operation (see fourth bullet above).  In other words, does operation exist in between action and real world result?  And what about the content of the message as stated in the third bullet above.

Obviously, there are some ambiguities here and I'd appreciate any help in the clarification so we can press ahead with the write-up.  In the meantime, I will describe and model a few common MEPs and include them in the write-up as well as the common interaction model that depicts the role of the service participants, agents, and intermediaries (PEP, PDP).

Cheers...

 - Jeff E.

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