Introduction to UML

1. Introduction to UML Todd BacastowPenn State UniversityGeography 583Geospatial System Analysis & Design

2. What is the UML? • Unified Modeling Language • It is a modeling language, not a process • In 1996, work on the UML was begun by Rational.

3. UML Diagrams • Class Diagrams • Use Case Diagrams • Collaboration Diagrams • Sequence Diagrams • Package Diagrams • Component Diagrams • Deployment Diagrams • Activity Diagrams • State Diagrams

4. Class Diagrams • Are the most fundamental UML Diagram. • Describe the classes in the system, and the static relationships between classes. • Class diagrams are used during Analysis, Design and Development.

5. UML Class Diagram Customer 1 Rental Invoice 1..* Rental Item 1 0..1 1 Checkout Screen DVD Movie VHS Movie Video Game

6. UML Class Diagram Multiplicity Customer Simple Aggregation 1 Class Abstract Class Rental Invoice 1..* Rental Item {abstract} 1 0..1 Composition (Dependency) Simple Association Generalization Checkout Screen DVD Movie VHS Movie Video Game

7. MyClassName +SomePublicAttribute : SomeType -SomePrivateAttribute : SomeType #SomeProtectedAttribute : SomeType +ClassMethodOne() +ClassMethodTwo() Responsibilities -- can optionally be described here. Parts of a Class • Classes can have four parts • Name • Attributes • Operations • Responsibilities • Classes can show visibility and types. • All parts but the Name are optional.

8. ThisOne : MyClassName +SomePublicAttribute : SomeType -SomePrivateAttribute : SomeType #SomeProtectedAttribute : SomeType +ClassMethodOne() +ClassMethodTwo() Object Diagrams • An Object is an instance of a class. • Object names are underlined. • Object diagrams are similar to class diagrams. Many of the same notations are used. • Object diagrams capture instances of classes, and allow the dynamic relationships to be shown.

9. Class and Object Diagrams Class Name Association Name Customer Rental Item Rents +id:integer +id:integer 0..n +name:string +released:date 0..1 Class Diagram Attributes Object Name Joe: Customer Casablanca: Movie +id:1667 +id:22340 +name:Joe Smith +released:1942 Object Diagram

10. Use Cases • Describe interactions between users and computer systems (both called actors) . • Capture user-visible functions. • Achieve discrete measurable goals. • Are typically used during Analysis and Design.

11. Use Case Actor Identify Movie Open Account Customer Clerk Return Movie Review In-Store Telephone Account Status Customer Customer Use Case Diagram

12. The Use Case Report provides documentation for the Use Case. A Use Case is not complete without the report. The elements of the Use Case Report are shown on the right. Brief description Precondition Flow of events Main flow Subflows Alternate flows Postcondition Special Requirements Enclosures Diagrams Pictures of the UI Use Case Report

13. Collaboration Diagrams • Collaboration diagrams describe interactions and links • Focus on exchange of messages between objects • Appears during Analysis phase • Enhanced during Design phase

14. Collaboration Diagram - Rent Movie :Rented Items Object 5: add(customer, movies) 1: enter_customer() 8: generateRentalTotal() 3: enter_movies() 2: IsValidCust(CustId) 7: print invoice() :Check-out Manager :Customer :Clerk 4:GetMovieByBarcode() :Inventory Message

15. Sequence Diagrams • Can be “morphed” from Collaboration Diagrams. • Describe interactions between objects arranged in time sequence • Focus on objects and classes involved in the scenario and the sequence of messages exchanged • Associated with use cases • Used heavily during Analysis phase and are enhanced and refined during Design phase

16. Sequence Diagram - Rent Movie :CheckoutMgr Cust:Customer :Inventory :RentedItems :Employee 1: find customer() 2: search (string) Object 3: enter movie() 4: search (string) Activation Message 5: rent (movie) 6: add(Cust, item) Lifeline 7: printInvoice() 8: generateRentalTotal()

17. Package Diagram Class Package

18. Component Diagram Component Interface Dependency Note

19. Deployment Diagram Node Communication Association

20. Activity Diagram Start State Identify Caller Action State Obtain Name & Address Decision Open Account? Current Customer? [no] [no] [yes] [yes] End State Create Account

21. Swimlanes and Fork/Join Points Customer Manager Walking Clerk Identify Movie Fork Point Place Order Place Order Fill Order Pay Collect Money Pickup Movie Deliver Movie Join Point

22. State Diagram Guard Event Transition Action Activity State

23. UML Diagram Usage

24. Conclusion • UML is a robust notation that can express information gathered throughout a project’s lifecycle. • Adopting standard use of UML can improve communication between clients and developers. • UML can be used as an effective data modeling tool as well as an object modeling tool.