The Birth of Craftsmanship

Transcription

1 The Birth of Craftsmanship Robert C. Martin Object Mentor, Inc. objectmentor.com Copyright by Object Mentor, Inc All Rights Reserved

2 Our Craft: After years, we have a definition! 2

3 Electron Gun and Slit Electron Gun 3

4 Moving the slit, moves the spot. Electron Gun 4

5 What would two slits show? Electron Gun 5

6 Two Spots? Electron Gun 6

7 7 Yikes Stripes!

8 Yikes! Stripes! Electron Gun 8

9 What if electrons are waves? Electron Gun? 9

10 Then the waves would interfere. Electron Gun 10

11 So let s shoot them one at a time. Electron Gun 11

12 OK, let s watch the slits. Detector Electron Gun Detector 12

13 Detectors off. Pattern returns. Detector Electron Gun Detector 13

14 This is a picture of a single electron. Electron Gun 14 But only if we don t watch it pass through the slits.

15 This is 60,000 individual electrons. 15

16 What have we learned from this? The world is not as it appears to our common sense notions. or If you think you understand QM, then you are missing something. 16

17 17 But we re supposed to be talking about our Craft

18 Prehistory: The dark times. 70 s-90 s 18

19 19 We believed in big plans.

20 Object Mentor s Third Law of Agile Development In preparing for battle I have always found that plans are useless, but planning is indispensable. Dwight David Eisenhower 20

21 Booch s Common Sense Example The Doghouse vs. the Skyscraper. 21

22 And then there s this 22

23 Object Mentor s First Law of Agile Development A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over, beginning with a working simple system. Systemantics: How Systems Really Work and How They Fail, 2d. ed., J. Gall, The General Systemantics Press, 1986, p

24 The Waterfall Model Managing the Development of Large Software Systems Dr. Winston W. Royce May 1 Jul 1 Sep 1 Nov Analysis Design Implementation DFD ERD DD ST 24

25 Royce s actual diagram. 25

26 Royce s Observation 26

27 Royce s Conclusion 27

28 But the data says something different 28

29 Over specification. 29

30 Long Projects Fail. 30

31 Object Mentor s Second Law of Agile Development...the document-driven, specify-then-build approach... lies at the heart of so many... software problems. Fred Brooks in his 1987 Report of the Defense Science Board Task Force on Military Software 31

32 1992:Jack Reeves C++ Journal What is Software Design? 32

33 Blueprints and Source code. Jack Reeve s article: public int score() { int score = 0; int frameindex = 0; for (int frame = 0; f if (isstrike(framei score += 10 + str frameindex++; } else if (isspare( score += 10 + spa frameindex += 2; } else { score += sumofbal frameindex += 2; } } return score; } 33

34 What if houses were like software? Construction costs nothing. Design is everything. Every design change costs $

35 : Principles & Patterns

36 SCRUM 1995 PLoP ~muddle~ 36

37 Space: 1999 XP 37

38 38 Short Iterations

39 TDD Refactoring Simple Design 39

40 Continuous Integration Pairing 40

41 Excitement: The Techie Practices 41

42 Revulsion: No Architecture! No Design! 42

43 : XP Immersion

44 XP Leadership Hillside Burnout. The Two Martins. 44

45 45 Lightweight Process Summit

46 Snowbird Agile Manifesto Agile Coined Most important Most damaging 46

47 47 XP Scrum FDD DSDM XTAL

48 Agile Stimulated SCRUM Scrum subset of XP 48

49 Ron s Circle of Life Whole Team Continuous Integration Test Driven Development Collective Ownership Acceptance Tests Pairing Refactoring Planning Game Metaphor Simple Design Sustainable Pace 49 Small Releases

50 50 SCRUM doesn t smell like GEEKS

51 51 SCRUM makes Agile palatable to Business.

52 2002: CSM #1 meh. 52

53 SCRUM certification gold rush Attracted Business attention. 53

54 But Agile, Scrum, XP were for: Small teams. 54

55 55 RIP: SOS

56 Aunt Mary. LEAN Agile in the Large. 56

57 Engorged SCRUM 57

58 SCRUM Certification & Lean Scrum crossed the Chasm and penetrated business. 58

59 59 But something was left behind

60 Tech Practices! Test Driven Development Pairing Refactoring Simple Design 60

61 61 Scrum

62 It s the worst case scenario: No Design. No Architecture. Just Rapid Churn. 62

63 63 How many of you have been significantly impeded by Bad Code.

64 To make matters worse The mess doesn t show up right away. 64

65 The Flaccidity Curve Productivity vs Ti Time 65

66 66 Seeming fast is not BEING fast.

67 Scrum-ED: Agile->Stimulated, Lean->Engorged, No tech->flaccidated. 67

68 68 But Agile Exposes this problem so that the Business can see it!

69 69 Because velocity is measured and reported

70 70 To improve velocity Scrum Teams must adopt TDD, CI, Pairing, simple design, refactoring. (XP)

71 Agile is the gateway To Craftsmanship To a Profession 71

72 Craftsmanship: Professionalism: The Next Big Thing 72

73 73 TDD / Refactoring

74 74 Clean Code

75 75 Boyscout Rule.

76 The only way to go fast is to go well, and to write 76

77 77 Code This Good.

78 The Green Band 78

79 Craftsmanship Manifesto manifesto.softwarecraftsmanship.org 79

80 Contact Information Robert C. Martin Websites: manifesto.softwarecraftsmanship.org 80