1. By SmartBoard Team

2. Agenda
 Scenario & Writing UML
 Discuss with each team’s UML
 What if…
 BMVV design
 Strategy pattern
 Applied with BMVV design
 More exercise..

3. Scenario
 Act yourself as Car company owner
 Car component will consist of
 Engine Type
 Fuel used
 Nitrous (Additional boost)

4. Scenario (2)
 From its components, we can calculate
the fuel burn rate. So, it should include method
getBurnFuel(double distance).
It comes from Engines power + Nitrous power (if used)
 Each car can used only
 One type of engine
 One type of Fuel
 One type of Nitrous
 You need some program to
show fuel burn rate for each car
 Car components can be changed in the future.
 Every team, please write UML Class diagram to
according to the requirement above…

5. Writing UML ~10-15 min
Take your time…

6. Time’s up….
 Let’s see your UML diagram

7. What if..
 More engine type is added
 More fuel type is added
 More nitrous type is added
 Some car can’t use some engine
 No more benzene ??
 Can you design support this changes?

8. Let’s record your problem

9. BMVV Car company design
B
cd Car
Car
# engine: String
# fuel: String
# boost: String
- accel: double
+ setBoost(String) : void
+ setEngine(String) : void
+ BurnFuel(double) : double
+ getFuelName() : String
+ getEngineName() : String
+ getBoostName() : String
# getBurnFuel(double) : double
+ performBoost(double) : double
JazzCar TankCar
PorcheCar
+ JazzCar() + TankCar()
+ PorcheCar()

10. BMVV Car company design #2
B
protected double getBurnFuel(double distance)
{
if(engine.equalsIgnoreCase("1500CC")
cd Car && fuel.equalsIgnoreCase("Benzene"))
{
Car double consume = distance*0.054;
consume = consume*18/17;
# engine: String return consume;
# fuel: String }
# boost: String else if(engine.equalsIgnoreCase("1500CC")
- accel: double
&& fuel.equalsIgnoreCase("Diesel"))
{ ………….. }
+ setBoost(String) : void
else if(engine.equalsIgnoreCase("1500CC")
+ setEngine(String) : void
&& fuel.equalsIgnoreCase("Gasohol"))
+ BurnFuel(double) : double
+ getFuelName() : String
{ ………….. }
+ getEngineName() : String else if(engine.equalsIgnoreCase("1900CC")
+ getBoostName() : String && fuel.equalsIgnoreCase("Benzene"))
# getBurnFuel(double) : double { ……. }
+ performBoost(double) : double …………..
…….
…
JazzCar TankCar
PorcheCar
+ JazzCar() + TankCar()
+ PorcheCar()

11. Problems occurs when…
 If 4500cc engine are added
 No more benzene used.
 Super Gasohol is invented.
If each case has more
 else if(engine.equalsIgnoreCase(“4500CC”)
&& fuel.equalsIgnoreCase(“Benzene”))
{ conditions….
else if(engine.equalsIgnoreCase(“1500CC”)
&& fuel.equalsIgnoreCase(“SuperGasohol”))
}
{ …… if(engine.equalsIgnoreCase(“4500CC”)
else }
&& fuel.equalsIgnoreCase(“Diesel”))
{
else if(engine.equalsIgnoreCase(“1900CC”)
}
&& fuel.equalsIgnoreCase(“SuperGasohol”))
else if(engine.equalsIgnoreCase(“4500CC”)
{ && …Another fuel type… )
…… }
.
.
.
else if(engine.equalsIgnoreCase(“4500CC”)
&& fuel.equalsIgnoreCase(“SuperGasohol”))
{ …… }

12. Unable to encapsulates data
 According to this design, if you company
need to outsource your work…
Con
fide
ntia
l
$ $ $$$

13. Strategy patterns
 Define a family of algorithms, encapsulate, and
make them interchangeable. Strategy lets the
algorithm vary independently from clients that
use it.
http://en.wikipedia.org/wiki/Strategy_pattern

14. Thai military communication
network
Every message will be
encrypted.
Communication between
a station and an unite

15. Old cipher machine model
Break encapsulation rule
(RTA,2)
Conditions
2. decryptA
Machine 3. decryptB
4. decryptC
5. None
SUB
1500 lines

16. New cipher machine model
Alternative
subclass
<interface>
(RTA, object)
Object.decrypt(“RTA”)
decryptB
Machine decryptA
Eliminate
conditions Family of
A choice of
algorithms implementation
SUB None
s

17. New cipher machine model
 Decrypt A and B can use signature only a
string. Object.decrypt(String);
 But Decrypt C need more parameters.
Object.decrypt(String, int);
Communication
 So method signature should have two
overhead
parameters. Object.decrypt(String, int);
 Ex . ObjectA.decrypt(“RTA”, Null);
ObjectB.decrypt(“RTA”, Null);
ObjectC.decrypt(“RTA”, 366);

18. Consequences
 Families of related algorithms.
 An alternative to subclassing.
 Strategies eliminate conditional statements.
 A choice of implementations.
 Clients must be aware of different
strategies.
 Communication overhead between Strategy
and Context.
 Increased number of objects.

19. Another example : Sort
 Assume that, you need to write a sort program
 There’re many kinds of sort..
 Strategy is what we group the many algorithms
that do the same things and make it
interchangeable at run-time
Ascending
Bubble Sort
Runtime
Sort SortStrategies
Selection
Descending Sort
Sort
Input Result
Quick Heap
#2
#1 #2
#1
Sort Sort

20. Another example : Sort #2
Change the algorithm
at runtime

21. Apply strategy with BMVV design
 Indicates the problem..
I
cd Car
Car
# engine: String
# fuel: String
ntain
# boost: String
mai
- accel: double
rd to
+ setBoost(String) : void
+
+
+
setEngine(String) : void
BurnFuel(double) : double
getFuelName() : String
Ha
+ getEngineName() : String
+ getBoostName() : String
# getBurnFuel(double) : double
+ performBoost(double) : double
JazzCar TankCar
PorcheCar
+ JazzCar() + TankCar()
+ PorcheCar() Move it to the new class…

22. Apply strategy with BMVV design
Need getBurnFuel() So as Nitrous
 Re-designing
from different factor

23. Apply strategy with BMVV design Engine4500ccBenzene Engine4500ccGasohol Engine4500ccDiesel
 Overall design
O
If 4500cc engine is added?
cd carPattern
Engine1500CCBenzene
+ getBurnFuel (double) : doubl e Engine1900CCBenzene Engine1900CCDiesel Engine1900CCGasohol
+ getEngi neName() : Stri ng
+ getFuel Name() : Stri ng + getBurnFuel (doubl e) : doubl e + getBurnFuel(doubl e) : doubl e + getBurnFuel (doubl e) : doubl e
+ getEngi neName() : Stri ng + getEngi neName() : Stri ng + getEngi neName() : Stri ng
+ getFuel Name() : Stri ng + getFuelName() : Stri ng + getFuel Name() : Stri ng
Engine1500CCDiesel
+ getBurnFuel (doubl e) : double
NoBoost
+ getEngi neName() : Stri ng
+ getFuel Name() : Stri ng
+ getBurnFuel (doubl e) : doubl e
+ getFuel Name() : Stri ng
«i nterface» «i nterface»
Easier w
Engine1500CCGasohol Engine Nitrous
NitrousGasohol
hen doin
+ getBurnFuel (doubl e) : double + getBurnFuel (doubl e) : doubl e
+ getBurnFuel (doubl e) : doubl e + getFuel Name() : Stri ng
+ getEngi neName() : Stri ng
+ getEngi neName() : String + getBurnFuel (doubl e) : doubl e
g th e ma
+ getFuel Name() : Stri ng
+ getFuel Name() : Stri ng + getFuel Name() : Stri ng
intenanc
#engi ne #Boost
NitrousDiesel
Engine2500CCBenzene
+
+
+
getBurnFuel (doubl e) : doubl e
getEngi neName() : Stri ng
getFuel Name() : Stri ng #
#
Boost: Ni trous
engi ne: Engi ne
Car
+
+
e !!!
getBurnFuel (doubl e) : doubl e
getFuel Name() : Stri ng
NitrousBenzene
- Accel : doubl e
Engine2500CCGasohol + getBurnFuel (doubl e) : doubl e
+ performBoost(doubl e) : doubl e
+ getFuel Name() : Stri ng
+ getBurnFuel (doubl e) : double + «property set» setBoost(Ni trous) : voi d
+ getEngi neName() : Stri ng + setEngi ne(Engi ne) : voi d
+ getFuel Name() : Stri ng + BurnFuel (doubl e) : doubl e
+ Run() : voi d
+ Fuel () : voi d
Garage
Engine2500CCDiesel
+ mai n(Stri ng[]) : voi d
+ getBurnFuel (doubl e) : doubl e JazzCar TankCar PorcheCar
+ getEngi neName() : String
+ getFuel Name() : Stri ng + JazzCar() + T ankCar() + PorcheCar()
+ Fuel () : voi d + Fuel () : voi d + Fuel() : voi d
If no more benzene?

24. Apply strategy with BMVV design
 How it works at runtime
It will call BurnFuel(double)
according to its engine
Jazz is changing its
engine

25. An action adventure game

26. Solutions of exercise

27. Q/A

28. References
 www.viewimages.com
 www.thailandstrategy.com
 http://www.maxituning.pl/archiwum/0412/pics/technik
a/nos2.jpg
 www.mysticcobra.net/system/
 http://jpfamily.net/Coolpix/NHRA/slides/
 http://www.robinstewart.com/products/graphics/gs_ic
on.gif
 www.freewarebox.com/screenshot_2476_clock.html
 http://tv.pcworld.hu/apix/0612/Data%20thief.png
 http://www.offthemarkcartoons.com/cartoons/