4+1 View Model

Architecture of software-intensive system can be described using multiple, concurrent views. Based on this fact Philipe Kruchten developed a view model consists of 5 views, that a software architect can look at a system. But why is this called 4+1 view model rather 5 view model ? The obvious reason is unlike four views one view shows the systems functionality from the view point of the outside world.

Following figure shows the 5 views, how they are related to each other and the diagrams used to explain each view.

Logical View

• Shows the parts that compromise the systems
• Represent a set of abstraction
• Emphasizes classes and objects

UML diagrams used

        Class diagram
        State diagram
        Object diagram

Process View

• Describes system processes

UML diagrams used

        Activity diagram

        Sequence diagram

        Communication diagram

Implementation View (Development View)

• Illustrates a system from a programmer’s perspective

UML diagrams used

         Component diagram

Deployment View (Physical View)

• Illustrates system execution environment
• Maps software artifacts to hardware that hosts them

UML diagrams used

         Deployment diagram

Use Case View

• Illustrates system functionality
• Captures user goals and scenarios
• Helpful in defining the structure and functionality in other 4 views

UML diagrams used

        Use case diagram