The system is bound to be complex, and how to describe a system clearly is the difficulty of architecture work. There are two kinds of architecture viewpoints, although each has its own emphasis, but they all lead to the same goal, both of which are the basic methods of software architecture. Chuxiong java Course/It should be noted that these two architectural views have slightly different definitions and understandings of views, and the views should be views.

"4+ 1" view model

In the face of complex and uncertain business needs, in order to avoid blind people touching the image, it is more effective to use views and viewpoints. PhilippeKruchten introduced the "4+ 1" view model in detail in his article "Architectural Blueprint-4+ 1" view model of software architecture. In this model, view refers to describing the system from the perspective of different stakeholders, which can be end users, developers or project managers. Therefore, these four views are logical view, development view, process view and physical view respectively. In addition, the view of "+1" is to select some use cases and scenarios to describe the architecture.

Development view: Development view describes the system from the perspective of programmers and software management. This view, also known as the implementation view, often uses UML component diagrams to describe the composition of the system.

Logical view: the logical view mainly describes the functions provided by the system to the end users. It generally corresponds to the class diagram and state diagram of UML tools.

Physical view: Physical view describes the system from the point of view of system engineer. This view focuses on the topological structure of software components in the physical layer and the physical connection between components, which is usually called deployment view. It is called deployment diagram in UML tools.

Process view: Process view deals with the dynamic aspects of the system, such as how the processes of the system communicate, and the runtime behavior, such as concurrency, distribution, integration, performance, scalability and so on. UML tools are represented by activity diagrams.

Scenario view: Scenario view uses some use cases or scenarios to describe the interaction between processes and objects, which is used to verify the architecture design and is also the starting point for testing the architecture prototype.