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FIGURE 2.11: Navigation state machine.
data formats that need to be specified for the computer-to-computer interac-
tions. Finally, the ODP technology viewpoint imposes some constraints on
the presentation, including, for instance, usability and accessibility standards
that need to be considered in the specifications.
In the enterprise viewpoint, we are concerned with the functionality avail-
able for obtaining and manipulating data, and the actions that the system
will take as a result. Intuitively, navigation deals with the sequence in which
enterprise objects and artefacts will be visited and modified.
A navigation specification can be obtained from the models of the en-
terprise specification by focusing on the interactions between the role pairs
identified previously and extracting the state machine describing just these
interactions (see figure 2.11). Such a diagram indicates the sequence in which
information is requested and provided in the steps of the dialogue between
the user and the machine. Each state will correspond to a group of pages or
forms, displayed to the user or soliciting information from them. The transi-
tions mark the stages in the progress of the dialogue.
2.10 Writing Enterprise Specifications
The ODP enterprise language does not prescribe any particular method
for building the enterprise specification of a system, as the approach taken
will depend very much on the system being specified, the business that it
will support and the constraints that arise from the environment in which the
system will operate. For this example, the following process has been followed:
