Emergent design

1. EMERGENT DESIGN
Varokas Panusuwan

2. DESIGN PATTERN
•
What is it?

3. PATTERNS

4. “The Pattern is in the
problem”
–Scott Bain

5. Problem
Pattern
Don’t solve the problem, discover the problem.

6. Christopher Alexander, Architect
Design: the process of inventing things which display
new physical order, organization, form, in response
to function.

7. ce
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rc
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Force
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Fo
Design
Force
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rc
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Force
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8. Force
Force
Force
Force
Force
Force
Force
Design
Force

9. ce
e
rc
Fo
Force
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Fo
Fo
rc
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ce
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Design
Force

10. DESIGN PATTERN
•
Language for design
•
“Noobs vs Pro talks”

11. COMMONALITY
VARIABILITY
ANALYSIS
ANALYSIS
ANALYSIS

13. 5 Each

14. Browser:
"As a URLReader, I can read HTML either from File location
(file:///) or over internet (http://)"

15. loading...
Browser:
"As a Renderer, I want to show image as "loading..." until the
image is loaded

16. PROGRAMMING BY
INTENTION
•
Google Example

17. PATTERNS DISCOVERY
PRACTICES
•
Don’t worry about “creational pattern” yet.

18. ECHO HELLO WORLD
•
A program read input from keyboard or scanner
•
A program sends the output to either printer or
screen

19. DOM
•
Element are the things that
can be shown on screen
•
element can contain each
other
•
A browser can call render()
and the element should
render itself and everything
inside

20. SWING BORDER
•
Component can have borders
•
Borders can be stacked on top of
each other
•
Many kinds of border
•
•
Plain border
•
•
Image border
Dotted border
When render() the component
draw itself and the border

21. ENCRYPTION
•
An encryption module can encrypt a plain string to encrypted string
•
Many standards : DES, AES, Blowfish
•
Some encryption standards are composite of others
•
e.g.
•
3 DES = DES(DES(DES(text)))
•
DESAES = DES(AES(text))

22. ทอนเงิน
•
ทอนด้วยแบงค์ 500 จนกว่าจะทอนไม่ได้ นับจำานวนไว้
•
ทอนด้วยแบงค์ 100 จนกว่าจะทอนไม่ได้ นับจำานวนไว้
•
ทอนด้วยแบงค์ 50 จนกว่าจะทอนไม่ได้ นับจำานวนไว้
•
ทอนด้วยแบงค์ 20 จนกว่าจะทอนไม่ได้ นับจำานวนไว้
•
ทอนด้วยแบงค์ 10 จนกว่าจะทอนไม่ได้ นับจำานวนไว้

23. CREATIONAL PATTERNS
•
What can exist in the world?

24. FACTORY
•
Few possible configuration
•
Defined statically in code

25. BUILDER
•
Many possible configuration
•
Some rules coded in
•
Use in runtime to set up other objects

26. DESIGN TOOLS
•
CVA
•
Redundancy
•
Coupling
•
Encapsulation

27. COUPLING
•
Accidental
•
Intentional

28. ENCAPSULATION
switch (input) {
Program
Algo
case A : doAlgoA();
case B : doAlgoB();
AlgoA
}
AlgoB

29. LEVELS
•
Conceptual
•
Specification
•
Implementation
http://www.syntropy.co.uk/papers/modelingwithpurpose.
pdf

31. UNFIT PATTERNS
•
Handlers
•
Decorators

32. EMERGENT DESIGN
•
At Last
•
What is it?

33. Starbucks
1.
2.
1.
2.
3.
3.
4.
1.
2.
3.
4.
5.
6.
Create a software for cashier and barista
A program accepts order from user (cashier as them)
example:
What kind of coffee
What size etc
A program compute cost based on the order
A program shows the barista what to do
example:
Put in 2x coffee
Put in milk
put in ice
shake
done

34. Starbucks (v1)
1.
2.
Select Size of cup (S,M,L)
put coffee
a. (S) Cup -> Coffee
b. (M) Cup -> Coffee x 2
(L) Cup -> Coffee x 3

35. Starbucks (v2)
1.
2.
3.
a.
b.
Select Coffee Type (Hot/Cold)
Select Size of cup (S,M,L)
Make Coffee
Hot :: Cup -> Coffee (S,M,L)
Cold :: Cup -> Coffee (S,M,L) -> Ice (always x 1)
-- redraw this(keep v1) --

36. Starbucks (v3) redraw this
-1.
a.
b.
c.
2.
3.
a.
b.
c.
Select Coffee Type (Hot/Cold)(keep v1&v2) -Americano
Espresso
Latte
Select Size (S,M,L)
Make Coffee
Coffee
i.
Americano = Coffee + Water
1.
Latte = Coffee + Milk
a.
Espresso = Coffee + (nothing)
Hot :: Cup-> Coffee (S,M,L)
Cold :: Cup -> Coffee (S,M,L) -> Ice (always x 1)

37. `
What is the differences
between requirement and
design?