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Activities, Models and Modules


As seen in the previous chapter, the SOMT method describes object oriented analysis and design as a number of activities that produce one or more models. A model is here used in an abstract fashion to denote a collection of diagrams, text documents or whatever is needed in the particular model. The concept of a model is used to be able to discuss the results of an activity without going into detail of how the actual diagrams/documents are organized.

A module, on the other hand, is the concept used in SOMT to define how the diagrams/documents are organized. The major purpose of the modules is that they form units that should be fairly self-contained and that can be developed by themselves, maybe by different teams. A module is a container of e.g. diagrams and textual documents that has no semantics by itself but that forms a scope unit for names (if this is not given by the notation used). For example, if the Analysis Object Model is described in two modules that both contain a class called "Person", then these definitions do not refer to the same class. There will be two different "Person" classes, one in each module.

In practice it is beneficial to have a simple mapping between models and modules, either a one-to-one or, if a model is too large, a one-to many mapping where a model is decomposed into several modules.

The actual documentation produced according to SOMT is thus a collection of modules containing diagrams/documents that together form this particular projects representation of the SOMT models.


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