CSC307 Lecture 10

Introduction to Software Engineering
Patterns II
(202407)

1. Dr. Javier Gonzalez-Sanchez javiergs@calpoly.edu www.javiergs.info o ffi ce: 14 -227 CSC 307 Introduction to Software Engineering Lecture 10. Patterns
2. Technical Debt 2
3. Previously
4. Relationships 4
5. Standard Solutions
6. De f inition • Design patterns a re solutions to softw a re design problems you f ind a g a in a nd a g a in in re a l-world a pplic a tion development. • P a tterns a re a bout reusable designs a nd inter a ctions between objects. • The 23 G a ng of Four (GoF) patterns a re gener a lly considered the found a tion for a ll other p a tterns (G a mm a , Helm, Johnson, a nd Vlissides). 6
7. GoF Patterns 7
8. Singleton
9. Singleton 9
10. Singleton class Singleton{ private static Singleton _instance; // Constructor is 'protected' protected Singleton() {} public static Singleton getInstance(){ if (_instance == null){ _instance = new Singleton(); } return _instance; } } 10 https://github.com/CSC3100/Patterns
11. Singleton 11 https://github.com/CSC3100/Patterns
12. Warning 12 Do not Abuse of the Singleton You are transforming OOP into Structural Programming!! 🙈
13. Homework 13 Reading https://medium.com/javarevisited/design-patterns-101-hello-singleton-2d3f227c7729
14. Observer
15. Observer 15
16. Classroom | Initial Version 16 https://github.com/CSC3100/Patterns
17. Student | Initial Version 17 https://github.com/CSC3100/Patterns
18. Teacher | Initial Version 18 https://github.com/CSC3100/Patterns
19. Observer 19
20. Observer 20 https://github.com/CSC3100/Patterns
21. Observable 21 https://github.com/CSC3100/Patterns
22. Classroom | New Version 22 https://github.com/CSC3100/Patterns
23. Student | New Version 23 https://github.com/CSC3100/Patterns
24. Teacher | New Version 24 https://github.com/CSC3100/Patterns
25. Important 25 Do not reinvent the wheel! (Do not make another implementation for classes Observer or Observable -they already exist in libraries!)
26. Important 26 Depreciated java.util.Observer java.util.Observable The implementation of these packages That is NOT about the Observer pattern being depreciated.
27. Important 27 Use java.beans.PropertyChangeListener java.beans.PropertyChangeSupport
28. Classroom | Listener Version 28 https://github.com/CSC3100/Patterns
29. Student | Listener Version 29 https://github.com/CSC3100/Patterns
30. Teacher | Listener Version 30 https://github.com/CSC3100/Patterns
31. Thoughts? 31
32. Homework 32 Reading https://medium.com/swlh/software-design-patterns-why-what-and-an-example-8d4c0934a6ca
33. Questions 33
34. Lab.
35. To Do 35 We need a Tool
36. Tools We need a Tool
37. astah.net 37 https://astah.net/products/students/
38. File | New (projet) 38
39. Create Diagram | Class Diagram 39
40. Tools For the rest of this course Do your Class Diagrams in
41. To Do 41 Create a Class Diagram
42. CSC 307 Introduction to Software Engineering Javier Gonzalez-Sanchez, Ph.D. javiergs@calpoly.edu Winter 2026 Copyright. These slides can only be used as study material for the class CSC307 at Cal Poly. They cannot be distributed or used for another purpose.