CSC310 Lecture 05

From Requirements to Design
(20260909)

Transcript

1. CSC 3100 Software Engineering Lecture 05. From Requirements to Design Dr. Javier Gonzalez-Sanchez javiergs@calpoly.edu www.javiergs.info ffi o ce: 14 -227
3. Activities 3
4. Where We Are Wants / Needs User Stories Accepted Backlog Design We know WHAT the system should do. Before N developers start coding… How do we decide HOW the pieces fit together? Design gives the team a shared blueprint. 2 4 Tasks
5. De inition Software Design To cre te speci ic tion of softw re (solution) Gr phic l Abstr ct Description (blueprint) a f a a a a a f a a 5 model
6. The Software Skateboard It is the smallest useful working system small working system more capability fuller product A skateboard is not 25% of a car Our first design should give every important capability a place to grow —without building everything now. 6
7. Requirements Are Not Classes Requirement Responsibility Possible Design Element Send Message coordinate sending MessageService Store Messages preserve messages MessageRepository Authenticate User verify identity AuthenticationService Gather Robot Pose obtain device data RobotDataSource Stories describe behavior. Design organizes responsibilities. 7
8. One Story → Design → Code REQUIREMENT DESIGN IMPLEMENTATION VERIFICATION #5 Send Message MessageService ↓ CommunicationService Java classes + interfaces Automated test with mock User-visible behavior The requirement did NOT say: • MessageService • interface • MQTT Those are DESIGN decisions. 7 8 CSC 3100 • Software Design
9. Questions to Ask While Designing • What needs to KNOW something? • What needs to DO something? • What information needs to EXIST? • Which responsibilities belong together? • Which dependencies should be interfaces? • What can we mock today? • Can we trace every design element back to a requirement? 11 9 CSC 3100 • Software Design
10. The Backlog Suggests Responsibilities Messaging Data Security Send / Receive Retry / Encrypt Store / Retrieve Robot pose / Eye tracking Register / Authenticate Authorize / Audit Devices Visualization Monitoring Robot / Accelerometer LiDAR Dashboard / History Robot / Map Data availability Failures This is a design hypothesis—not the final answer. 9 10 CSC 3100 • Software Design
12. Blueprints Diagrams
13. Structur l models of softw re displ y the org niz tion of system in terms of ) the p rts (items, elements, components) th t m ke up th t system nd b) their rel tionships. a a a a a a a a a a a 13 a a Structural models
14. Blueprints VS 14
15. Error Smells
16. Level of Abstraction https://faculty.runi.ac.il/arik/site/Clipasso.asp 16
17. Relationships 17
18. What Comes Next? Today Requirements Design Tasks Implementation Tests Pull Request A shared design allows N developers to build ONE system. Next: turn the design into implementation Tasks. 13 18 CSC 3100 • Software Design
19. Questions 19
20. CSC 3100 Software Engineering Javier Gonzalez-Sanchez, Ph.D. javiergs@calpoly.edu Fall 2026 Copyright. These slides may be used only as study material for CSC 5100 within the California State University system. They may not be distributed or used for any other purpose.