CSC307 Lecture 09

Introduction to Software Engineering
Patterns
(202407)

Transcript

1. Dr. Javier Gonzalez-Sanchez javiergs@calpoly.edu www.javiergs.info o ffi ce: 14 -227 CSC 307 Introduction to Software Engineering Lecture 09. Patterns
2. Previously
3. Relationships 3
4. Standard Solutions
5. 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). 5
6. GoF Patterns 6
7. Singleton
8. Singleton 8
9. Singleton class Singleton{ private static Singleton _instance; // Constructor is 'protected' protected Singleton() {} public static Singleton getInstance(){ if (_instance == null){ _instance = new Singleton(); } return _instance; } } 9 https://github.com/CSC3100/Patterns
10. Singleton 10 https://github.com/CSC3100/Patterns
11. Warning 11 Do not Abuse of the Singleton You are transforming OOP into Structural Programming!! 🙈
12. Homework 12 Reading https://medium.com/javarevisited/design-patterns-101-hello-singleton-2d3f227c7729
13. Observer
14. Observer 14
15. Classroom | Initial Version 15 https://github.com/CSC3100/Patterns
16. Student | Initial Version 16 https://github.com/CSC3100/Patterns
17. Teacher | Initial Version 17 https://github.com/CSC3100/Patterns
18. Observer 18
19. Observer 19 https://github.com/CSC3100/Patterns
20. Observable 20 https://github.com/CSC3100/Patterns
21. Classroom | New Version 21 https://github.com/CSC3100/Patterns
22. Student | New Version 22 https://github.com/CSC3100/Patterns
23. Teacher | New Version 23 https://github.com/CSC3100/Patterns
24. Important 24 Do not reinvent the wheel! (Do not make another implementation for classes Observer or Observable -they already exist in libraries!)
25. Important 25 Depreciated java.util.Observer java.util.Observable The implementation of these packages That is NOT about the Observer pattern being depreciated.
26. Important 26 Use java.beans.PropertyChangeListener java.beans.PropertyChangeSupport
27. Classroom | Listener Version 27 https://github.com/CSC3100/Patterns
28. Student | Listener Version 28 https://github.com/CSC3100/Patterns
29. Teacher | Listener Version 29 https://github.com/CSC3100/Patterns
30. Thoughts? 30
31. Homework 31 Reading https://medium.com/swlh/software-design-patterns-why-what-and-an-example-8d4c0934a6ca
32. Questions 32
33. Lab
34. 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.