1 Aspects of IEEE P1471 Viewpoints in Unified Modeling Language (UML) Manzur Ashraf, BRAC University Humayra Binte Ali, Dhaka University Md.Mahfuz Ashraf, BRAC University ICCIT 2004, BRAC University

2 Terminologies View: One system can be described by 1-many views (conception/ idea) and each view can be described by 1- many graphical/textual Model (Symbol) Viewpoint: To apprehend views at a certain level of detail [Roel] Meta-layer/Meta-meta layer concept (in UML)is bounded. To conceive external concepts we use Extension mechanism (UML). To make generalized viewpoints IEEE P1471 (98) Fit UML to IEEE P1471

3 Classification 1 Rich Hillard clustered the IEEE P1471 constructs in different conceivable groups. A)Structural viewpoint B)Behavioral viewpoints C)User viewpoint D)Distribution Viewpoint

4 A) Structural viewpoint: Concerns: – Defines the computational elements of a system and the organization of those elements. – What software elements comprise the system? What are their interfaces? How do they interconnect? What are the mechanisms for interconnection?

5 In UML, A class diagram depicts the static structure of a system in terms of object classes, their attributes and operations and their relationships with one another. Each class represents unique structure and a common behavior. A class diagram can capture many other types of application semantics, such as association roles, role constraints, association classes, abstract classes, abstract operations, polymorphic operations, derived elements, class-scope attributes and operations, generalization discriminators, and semantic constraints among subclasses. Hence class diagram validates structural model according to IEEEP1471.

6 B) Behavioral viewpoints: Concerns: – Expresses the dynamic actions of and within a system. - What are the kinds of actions does the system produce and participate in? How do those actions relate (ordering, synchronization, etc.)? What are the behaviors of system components? How do they interact? Here Modeling Methods are events, processes, states and operations on those entities.

7 - In UML, A state diagram depicts the various state transitions or changes an object can experience during its lifetime, along with the events that cause those transitions. -In UML, activity diagram represents internal process flow as opposed to processes controlled by external events. The state represents performance of the actions and transitions are triggered by completion of the actions.

8 In UML, an interaction diagram is used to show the pattern of interactions among objects for a particular use case. There are two types of interaction diagrams. 1) Sequence diagrams show the explicit sequencing of messages, 2) collaboration diagrams show the relationship among objects. Both are useful for developing a dynamic model of a system in terms of object interactions. Objects communicate with one another by sending messages.

9 C) User viewpoint: Concerns: – Captures the purpose, scope and policies for the system. – Roles played by the system. – Activities undertaken by the system. – Policy statements about the system.

10 A use case model is developed during the early phase of requirements analysis. Use case modeling helps developers gain a clear understanding of the functional requirements (overview) of the system, without having to worry about how those requirements would be implemented. It represents a sequence of actions initiated by an actor.

11 D) Distribution Viewpoint: Concerns: - Defines how Command, Control information and capabilities will be distributed. - Defines how enterprise data is defined, organized (structured), accessed and maintained. - What runs where? What talks to what? How do they talk? Distribution includes location and mechanisms to provide both transport and access between processes.

12 In UML, distribution viewpoint is performed by implementation diagram. Two types of implementation diagram are possible: a) Component diagram shows the structure of the source code and the relationship between modules; b) Deployment diagram shows the structure of the run-time environment and the physical structure of the installed platform/hardware on which the system is installed (running).

13 Classification 2 A.Conceptual and analysis viewpoints: The objective is to highly abstract software descriptions. B.Logical design viewpoint: The objective is to describe the software design C.Environmental / Physical viewpoint: The objective is to focus on the environment and physical aspects of the software. Roel W. clustered the IEEE P1471 constructs in different conceivable groups.

14 Conceptual and analysis viewpoints ViewpointUML diagramDescription Analysis focusedClassDescribe system entities in response to a scenario Analysis interactionInteractionInteraction diagram between objects for analysis Analysis overallClassCombination of all classes from all focused analysis viewpoints ContextUse caseShow the external system actors and the system under design

15 logical design viewpoints ViewpointUML diagramDescription Component Component communication (static) Component interactionInteractionInteraction among components Component stateStateComponent state transition Layered subsystemPackageLayering and subsystems design Logical dataClassCritical data views for integration Subsystem interface dependency ClassSubsystem dependencies and interfaces

16 Environmental and physical viewpoints ViewpointUML diagramDescription Deployment Mapping of software to hardware for distributed systems Physical dataDeploymentPhysical view of a particular database ProcessDeploymentShow the processes of a particular system instance Process stateStateShow the dynamic states of a process