UML – Unified Modelling Language For Effective OO Development

1. UML – Unified Modelling LanguageFor Effective OO Development Yves Holvoet Rational Software Corporation (say Eve Olvoot)

2. Agenda • Modelling • Why? • Levels of Abstraction • 5 Views and 2 dimensions of System Architecture • UML • History • 10 diagrams • Summary

3. The Importance of Modeling

4. What Is a Model? • A model is a simplification (abstraction) of reality.

5. Abstraction • Is conceptual and captures the essential characteristics of an entity that distinguish it from all other kinds of entities. • Defines a boundary relative to the perspective of the viewer.

6. Instance myAccount : BankAccount yourAccount : BankAccount • Is an actual entity instance of the conceptual abstraction. • All instances of a given abstraction share a common structure (data and behavior as described in the Abstraction).

7. Levels of Abstraction Scenario High Level object object Is an instance of Is an abstraction for Low Level Processor Processor Type

8. Modeling Process Modeling Process Business Business Business Use Cases - Activities Business Use Cases - Activities High Level Use Cases Scenarios Classes Objects System Abstraction Instance Sources Processes Processors Low Level

9. UML 1 + 2 * 2 Views Layers Use Cases Packages Scenarios Logical View Use Case View Classes Objects Software Implementation View Sources Process View Tasks Packages Processes Layers Systems Hardware Deployment View Processors

10. 4 + 1 = 1 + 2 * 2 Views Logical View Logical View Use Case View Implementation View Implementation View Use Case View Deployment View Deployment View Process View Process View • The Use-Case view describes the behavior of the system in term of use-cases and scenarios • The Logical view packages the classes of the system and their relationships • The Implementation view describes the mapping of the logical classes to components of the target environment • The Process view deals with concurrency and synchronization • The Deployment view describes the mapping of the software on the hardware

11. Use-Case View Specification Class Validation DevelopmentPlan • 3MainBenefits Abstraction for many scenarios message instance of operation link instance of association object instance of class

12. Use Case View: Main Benefits • Specification • in terms of use cases • Development plan • lists iterations • assign scenarios to iterations according to their risk levels • Validation of classes • the necessary objects for the whole system are collectively all the objects participating in all scenarios • the messages between objects drive class relationships

13. Logical View Terminology Object Validation Development Teams • 3 Main Benefits Logical grouping of classes Strong inner coupling (cohesive classes) Weak outer coupling (for reuse, resilience)

14. Logical View: Main Benefits • Terminology • it provides vocabulary for common unambiguous understanding of the problem domain • Development Teams • they are derived from packages • packages are created to minimize the coupling • Validation of objects • the objects, links and messages must be in synch with class, relationships and operations

15. 2 Dimensions for Software Architecture Logical packages form horizontal layers where layers can only access what is below and not what is above Scenarios form vertical slices where each slice traverses all layers but only “hits” a small sub-set of the classes Rational Unified Process is: Architecture Centric Use Case Driven

16. Agenda • Modelling • Why? • Levels of Abstraction • 5 Views and 2 dimensions of System Architecture • UML • History • 10 diagrams • Summary

17. History of the UML Nov ‘97 UML approved by the OMG

18. UML Concepts • The UML may be used to visually model: • The interaction of your application with the outside world • Use Case Diagram • The behavior of your system • Interaction Diagram • The structure of your system • Class Diagram • Package Diagram • The components in your system • Component Diagram • Deployment Diagram

19. 10 UML Diagrams Activity Diagram Sequence Diagram Use Case Diagram Interaction Diagram (Scenarios) Collaboration Diagram Class Diagram (static part of class) State-Transition Diagram (behavioral part of class) Object Diagram Component Diagram (Sources & Processes) Deployment Diagram (Processors)

20. Use Case Diagram Request Course Roster Professor Student Register for Courses Billing System Maintain Course Information Registrar • Use case diagrams are created to visualize the interaction of your system with the outside world

21. Sequence Diagram registration registration math 101 : Student math 101 form manager section 1 1: fill in info 2: submit 3: add course(joe, math 01) 4: add(Joe) 5: are you open? 6: add (Joe) • A sequence diagram shows step-by-step what has to happen to accomplish a piece of functionality provided by the system

22. Collaboration Diagram course form : 1: set course info CourseForm 2: process 3: add course : Registrar theManager : aCourse : CurriculumManager Course 4: new course • A collaboration diagram displays object interactions organized around objects and their links to one another

23. Class Diagram RegistrationUser Student major Professor 3..10 CourseOffering 4 1 0..4 • A class diagram shows the structure of your software

24. 2 Main Relationships: Inheritance vs. Association Person Food <<deferred>> eat(Food) Vegan Vegetarian Omnivore eat(Food) eat(Food) eat(Food) pre-condition of eat() is: pre-condition of eat() is: No pre-condition at all for -Food parameter must be a -Food parameter must be either a eat() Vegetable Vegetable or Derived from Animal

25. The Physical World Register.exe Billing.exe Billing System People.dll User Course.dll Course • Component diagrams illustrate the organization and dependencies among software components

26. Deploying the System Registration Database Main Library Building Dorm • The deployment diagram visualizes the distribution of components across the enterprise.

27. Summary • Visual modeling can be used to: • Define business process • Communicate • Manage complexity • Define software architecture • Promote reuse • The UML is the standard language for visualizing, specifying, constructing, and documenting the artifacts of a software-intensive system

28. Questions?