Commenting “A scenario is a behavioral view”

In A scenario is a behavioral view – Orchestrating services by scenario integration it is proposed to capture service behavior in the form of a certain petri net class, especially oclets (which is an acyclic Petri net with a local precondition) and by this to model individual scenarios. A scenario is a partial execution of the service. The behavior of a service is defined by the set of scenarios for this service.

In my personal opinion the use of preconditions is a good thing in general. However in my opinion the splitting up of the whole behavior into different scenarios has also disadvantages. For example that it is not so clear, if one scenario is changed, which side effects this has on other scenarios. Also one transition for example can occur in different scenarios. Thereby probably many scenarios need to be changed, if the behavior of one transition needs to be changed. Also a problem is, that it is not so clear how to model differen alternative behaviors. If the union set of all scenarios describes the behavior of the service, it is all one. So for example if there is one big service, but the behavior can be different – for example in one case with confirmation, in another without confirmation – this is not possible to be modeled. It is just a “confirmation” scenario in the set, but it is not modeled, that is sometimes must be used, sometimes not.

Good is that in the end of the paper it is proposed to integrate the scenarios into one view. This I agree upon. My personal opinion is, that I would rather start with the integrated view. Because all the mentioned disadvantages are not there in this case.

But I admit, that the use case proposed in the paper may still be valid in a consulting experince, where the client already has described the behavior of his services in the form of scenarios. Then, the method proposed is a good way to unify them into the desired integrated view. This may also be supported by tools, which gives an additional value add.

Also notbody should be distracted by the notion of the modeling language. This is just the underlying logic. The same method can as well be transferred to industrial languages, as is proposed in the paper and as I believe. For example I see no reason why this should not be useable in a BPMN 2.0 orchestration model environment.

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