Architectural Viewpoints

Architectural Viewpoints

It would be hard work if every time you were creating a view of your architecture you had to go back to first principles to define what should go into it. Fortunately, you don’t quite have to do that.

In his introductory paper, Kruchten defined four standard views, namely, Logical, Process, Physical, and Development. The IEEE standard makes this idea generic (and does not specify one set of views or another) by proposing the concept of a viewpoint. The objective of the viewpoint concept is an ambitious one—no less than making available a library of templates and patterns that can be used off the shelf to guide the creation of an architectural view that can be inserted into an AD. We define a viewpoint (again after IEEE Standard 1471) as follows.

Definition: A viewpoint is a collection of patterns, templates, and conventions for constructing one type of view. It defines the stakeholders whose concerns are reflected in the viewpoint and the guidelines, principles, and template models for constructing its views.

Architectural viewpoints provide a framework for capturing reusable architectural knowledge that can be used to guide the creation of a particular type of (partial) AD.In a relatively unstructured activity like architecture definition, the idea of the viewpoint is very appealing. If we can define a standard approach, a standard language, and even a standard metamodel for describing different aspects of a system, stakeholders can understand any AD that conforms to these standards once familiar with them.In practice, of course, we haven’t achieved this goal yet. There are no universally accepted ways to model software architectures, and every AD uses its own conventions. However, the widespread takes us some way toward this goal.

In any case, it is extremely useful to be able to categorize views according to the types of concerns and architectural elements they present.

Strategy: When developing a view, whether or not you use a formally defined viewpoint, be clear in your own mind what sorts of concerns the view is addressing, what types of architectural elements it presents, and who the viewpoint is aimed at. Make sure that your stakeholders understand these as well.