On the 4+1 Architectural View Model

RJ: "Suppose you wanted to document the architecture of some system. How would the ideas in the 4+1 views paper help you? Or would they?"

The 4+1 views are very useful for documenting a system from the architectural point of view. The 4+1 model offers a way of looking at different aspects of the system in isolation, thus easing the complexity of analyzing the system.

The first four views represent the logical, development, process and physical aspects of the architecture. Highlighting some aspect while intentionally suppressing others offers a systematic and standardized way for documenting the various layers of the system. The fifth view is represented by use cases and scenarios that might further help with documenting the other views. Furthermore, when studied and documented together, the four plus one views make sure that no important aspect of the system is overlooked.

The separation of concerns achieved by the 4+1 model makes a documentation structured around it, a great tool for software architects as well as other stakeholders of the architecture: end-users, developers, systems engineers, project managers, testers, etc. Documents created using the 4+1 view process are easily used by all members of the development team.

Last but not least, the fact that one can naturally map UML diagrams to each individual model view speaks again for the 4+1 as being a great model for structuring one's documentation. For instance: class, communication and sequence diagrams can represent the logical view, component and package diagrams - the development view, activity diagrams - the process view, the deployment diagram - the physical view and finally the use case diagrams are a great tool to represent scenarios.