Presentation given at the Virtual JUG 21st Nov 2013. Video here: http://www.youtube.com/watch?v=GixwXNlZ7dI

1. #vJUG
Design is a Process, not a
Document
Trisha Gee, Java Driver Developer
@trisha_gee

2. Design: translate the
requirements in a
specification that describes
the global architecture and
the functionality of the
system.
http://homepages.cwi.nl/~paulk/patents/isnot/node4.html

3. Managing the Development of Large
Software Systems - Dr Winston Royce
http://www.cs.umd.edu/class/spring2003/cmsc838p/Process/waterfall.pdf

4. <This Page Left Intentionally Blank>
Agile Design

5. Design is a Process, not
a Document

6. The Problem

11. Constraints:

12. Backwards
Compatibility

13. > What do you want
to do?
>_

14. Design is a Process, not
a Document

15. Bugs and
Defects
Unknown
Architecture
On Time and
Under Budget
New Features
Inconsistencies
Lack of
Experience
Unclear
Objectives

16. Bugs and
Defects
Unknown
Architecture
On Time and
Under Budget
New Features
Inconsistencies
You Are Here
Lack of
Experience
Unclear
Objectives

17. Bugs and
Defects
Unknown
Architecture
On Time and
Under Budget
New Features
Inconsistencies
You Are Here
Lack of
Experience
Unclear
Objectives

18. Bugs and
Defects
...and here
New Features
Unknown
Architecture
...and here
On Time and
Under Budget
...and here
Inconsistencies
You Are Here
...and here
Unclear
Objectives
Lack of
Experience
...and here

19. Bugs and
Defects
...and here
New Features
Unknown
Architecture
...and here
On Time and
Under Budget
...and here
Inconsistencies
You Are Here
...and here
Unclear
Objectives
Lack of
Experience
...and here

20. Bugs and
Defects
...and here
New Features
Unknown
Architecture
...and here
On Time and
Under Budget
...and here
Inconsistencies
You Are Here
...and here
Unclear
Objectives
Lack of
Experience
...and here

21. Bugs and
Defects
...and here
New Features
Unknown
Architecture
...and here
On Time and
Under Budget
...and here
Inconsistencies
You Are Here
...and here
Unclear
Objectives
Lack of
Experience
...and here

22. Bugs and
Defects
...and here
New Features
Unknown
Architecture
...and here
On Time and
Under Budget
...and here
Inconsistencies
You Are Here
...and here
Unclear
Objectives
Lack of
Experience
...and here

23. Bugs and
Defects
...and here
New Features
Unknown
Architecture
...and here
On Time and
Under Budget
...and here
Inconsistencies
You Are Here
...and here
Unclear
Objectives
Lack of
Experience
...and here

24. Where do I start?

25. > You are in a cluttered code base.
Everywhere you turn you see
different people’s styles.
> There are bugs to be fixed, and
new features that must be
implemented.
> Some users suggest improvements to
your product, others will kill you
if you change a thing.
> What do you want to do?
> _

26. Maintainability
Spe
ed
Tes
tabi
lity
onsistency
C
si
on
C
cy
ten
s
ability
Read
Im
mu
t
ab
il
ity

27. Design Goals
• Consistency
• Cleaner design
• Intuitive API
• Understandable Exceptions
• Test friendly
• Backwards compatible

28. In The North Tower...

29. Lack of consistency

30. > What do you want
to do?
>_

31. Why bother?

32. Our Solution
• Static analysis
• Build tools
• Discipline

33. Win!

34. Meanwhile, in the East...

35. Other adventurers!

36. > What do you want
to do?
>_

37. Our Solution
• Get them onboard
• Use the Scala driver as the guinea pig
• Give Morphia some love
• Talk to Spring
• Tests are your friends

38. Lurking All Around...

39. Backward Compatibility

40. > What do you want
to do?
>_

41. Our Solution
• An architecture
• Supports both APIs
• ...bonus of supporting other APIs too
• Tests tell us if we’ve done it right

42. On the Southern Front

43. The Public API

44. > What do you want
to do?
>_

45. Our Solution

46. Our Solution
• Committees
• Documents / Spreadsheets
• Meetings
• Research

47. Our Solution
• Committees
• Documents / Spreadsheets
• Meetings
• Research
• Hack Days
• Conferences
• Early Access

48. Retrospective

49. I wish...
• I had asked more questions.
• Particularly “why”
• I better understood my priorities
• We could use the whiteboard more
• I had focussed on tests even more

50. Conclusion

52. Tools

53. Your Inventory
• Your Technical Skills
• Your Domain Knowledge
• Your Life Experience
• Your Questions

54. Environmental Inventory
• The Domain
• The People
• The Hardware
• Chosen Technology
• Existing Code / Application / Platform

55. Your Inventory Grows
• Skills you learn
• Tools you research
• Team changes

56. Some Examples
• Tests. Always a Good Thing
• Static Analysis
• An automated build
• Bug/feature tracker
• Visibility of WIP

57. Design is a Process, not
a Document

58. #vJUG
@trisha_gee
Questions
http://is.gd/java3mongodb