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. Homework Quiz 2
3. Previously
4. Relationships 4 Association Directed Association Reflexive Association Multiplicity Aggregation Composition Generalization Realization
5. Good Code vs Bad Code 5
6. Not Everything that Can be … Should be … 6
7. Not Everything that Can be … Should be … 7
8. Patterns
9. 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). 9
10. GoF Patterns 10
11. Singleton
12. Singleton 12
13. Singleton 13 https://github.com/CSC3100/Patterns
14. Singleton 14 https://github.com/CSC3100/Patterns
15. Warning 15 Do not Abuse of the Singleton You are transforming OOP into Structural Programming!! 🙈
16. Homework 16 Reading https://medium.com/javarevisited/design-patterns-101-hello-singleton-2d3f227c7729
17. Observer
18. Observer 18
19. Classroom | Initial Version 19 https://github.com/CSC3100/Patterns
20. Student | Initial Version 20 https://github.com/CSC3100/Patterns
21. Teacher | Initial Version 21 https://github.com/CSC3100/Patterns
22. Observer 22
23. Observer 23 https://github.com/CSC3100/Patterns
24. Observable 24 https://github.com/CSC3100/Patterns
25. Classroom | New Version 25 https://github.com/CSC3100/Patterns
26. Student | New Version 26 https://github.com/CSC3100/Patterns
27. Teacher | New Version 27 https://github.com/CSC3100/Patterns
28. Important 28 Do not reinvent the wheel! (Do not make another implementation for classes Observer or Observable -they already exist in libraries!)
29. Important 29 Depreciated java.util.Observer java.util.Observable The implementation of these packages That is NOT about the Observer pattern being depreciated.
30. Important 30 Use java.beans.PropertyChangeListener java.beans.PropertyChangeSupport
31. Classroom | Listener Version 31 https://github.com/CSC3100/Patterns
32. Student | Listener Version 32 https://github.com/CSC3100/Patterns
33. Teacher | Listener Version 33 https://github.com/CSC3100/Patterns
34. Thoughts? 34
35. Homework 35 Reading https://medium.com/swlh/software-design-patterns-why-what-and-an-example-8d4c0934a6ca
36. Test Yourselves
37. Problem • Im a gine a cl a ss Te a cher running in its own execution thre a d, forever gr a ding—recording gr a des a s a collection of numeric a l v a lues. • A p a nel (PrinterP a nel) would like to show the gr a des a s they a re gener a ted. • Another p a nel (St a tistic a lP a nel) would like to show re a l-time st a tistics a bout the gr a des (how m a ny p a ss a nd how m a ny f a il). 37
38. Questions 38
39. Lab.
40. Lab 40 Draft a Class Diagram
41. Code public class B implements E { public B() { C c1 = new C(); } public void method(X x) { x.m() B b = new B(); b.sleep(); } } public class Y { X x = new X(); B b = new B(); } public class A extends B { C c1, c2; public A() { c1 = new C(); } public void method() { D d = new D(); d.working(); } } public class X { B var = new A(); public void m() { double x – Math.sqrt(5); } }
42. Let’s work 42
43. CSC 307 Introduction to Software Engineering Javier Gonzalez-Sanchez, Ph.D. javiergs@calpoly.edu Spring 2025 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.