All Measurement Methods supported by VisualFSM measure functional size by identifying the discreet functions they perform for its users, measuring the Function size using their custom measurement models, than aggregate the size of all individual Functions to give the total size.
Each method has its own rules for identifying the discreet functions. In the first instance, VisualFSM makes the assumption that when applying their identification rules, each method will identify the same functions.
The VisualFSM Software Model therefore includes a generic Function Model which forms the basis of subsequent measurement by all methods (in the Professional Version it is possible to amend the generic model)
Building the Function Model
Specific instructions as to how the VisualFSM models are created are given later, however it is useful at this time to highlight 2 major features of VisualFSM which are applicable to the building of all the models.
When a FUR has been selected in the Explorer, the Function Modeler tab will be enabled, selecting this will give access to the Function Modeler. This is where the Function Model is built.
VisualFSM works on the principle that if it isn't documented you can't use it. To enforce this, when adding something to any model, the user is required to scan the FUR, identify the word, phrase or sentence that justifies addition and highlight it.
We will use the word "item" for something added to a Model. Once highlighted, right-clicking will bring up a context-sensitive menu from which the user can select the "item" to be added to the Model.
FUR Traceability. When any "item" is added to any Model, in almost all cases, the highlighted word, phrase or sentence used to select it is recorded. Subsequently, whenever that "item" is selected in a list, tree or diagram, if the context allows it, the FUR from which it is derived is located and displayed, and the actual word, phrase or sentence is highlighted.
In this way the measurement can be audited and check for correctness, this is important in both a training environment, where it is necessary to establish why a student has made a particular decision, but also in a contractual situation where the validity of a measure may be challenged.