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Problem Statement
What are they
Simple
Medium
Mature
Conclusion

Option C: Initial Analysis Class Model (ACM) - aka “robustness modelling”

Purpose: To ensure that any information relating to static elements is specified within Rose, using the analysis class stereotypes, described directly against the use case (in the tree view). Soda can present these ACMs as part of the Use Case document.

The prime purpose of this model is validate the flow, and to provide an alternative graphical representation of both the dynamic (the relations between the classes) and static (the analysis classes) nature of the flow. Where used for this purpose the ACM does not have a life beyond a cycle and is imbedded in the use cases (i.e. classes not reused beyond scope of individual Use Cases).

If option A or B is not used, then the description part of the analysis class is to be used.

Although the term “throwaway” may suggest a poor return on investment, it acknowledges the fact that in reality even formal ACMs “evolve” into design as the cycle matures, losing its original analysis semantics.

5: Extending the previous example

 

The model should only describe things that only appear in the flow, with active terms (such as rules and other business logic) described controllers, and structural terms as entities – but using the same terminology as used in the flow.

Conversely, the contrivance of controllers such as describing things as “XYZ Manager” (as in the following example) is not acceptable if it does not accurately depict what the flow of the use case is doing, as this exercise should describe the “real world” domain rather than along the path of a proto-design system domain. Therefore if controllers are to be introduced they should avoid ambiguous terms such as “Manager”; “Processor” or “Administrator”.

 : Example of ACM contrivance

The interactions between the entities can also be named to build an active narrative.

If it appears that the ACM cannot be written without adding additional classes, then the flow must be updated accordingly. If a whole new “branch” is identified in the ACM then this would typically necessitate an alternative flow.

: Example of identifying alternative flows

Advantages

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Simple to produce – does not require stable baseline

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Provides a visual way of validating use cases

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Genuine analysis activity – describing a flow using non-word format prevents laziness in describing flow of events

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No danger of ACM “evolving” into design model

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No maintenance issues

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Good at spotting genuine alternatives: for example the above example demonstrates that failures in authentication have not yet been considered by flow.

Disadvantages

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Throwaway nature hard to justify

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© 2002-2005 Codel Services Ltd

This paper has been prepared by Codel Services Ltd to illustrate how structured business modelling can help your organisation. Codel Services Ltd is an IT Consultancy specialising in business modelling. If you would like further information, please contact us at: Deryck Brailsford, Codel Services Ltd, Dale Hill Cottage, Kirby-Le-Soken, Essex CO13 0EN,United Kingdom. Telephone: +44 (0)1255 862354/Mobile: + 44 (0)7710 435227/e-mail: info@codel-services.com