3.2 The design model & Architectural design.ppt

software

1. THE DESIGN MODEL

2. DIMENSIONS OF THE DESIGN
MODEL
Process Dimension (Progression)
Abstraction Dimension
Data/Class
Elements
Interface
Elements
Architectural
Elements
Component-level
Elements
Deployment-level
Elements
Analysis model
Design model

3. INTRODUCTION
Thedesignmodelcanbeviewedintwodifferent
dimensions
(Horizontally)Theprocessdimensionindicatesthe
evolutionofthepartsofthedesignmodelaseach
designtaskisexecuted
(Vertically)Theabstractiondimensionrepresentsthe
levelofdetailaseachelementoftheanalysismodelis
transformedintothedesignmodelandtheniteratively
refined

4. INTRODUCTION
Thedesignmodelhasthefollowinglayeredelements
Data/classdesign
Architecturaldesign
Interfacedesign
Component-leveldesign
Deployment-leveldesign

5. DATA/CLASS DESIGN
Data/classdesigncreatesamodelofdataand
objectsthatisrepresentedatahighlevelof
abstraction
Thisdatamodelisrefinedintoprogressively
moreimplementation-specificrepresentations
thatcanbeprocessedbycomputerbased
systems

6. ARCHITECTURAL DESIGN
Architecturaldesignforthesoftwareisequivalentto
the‘floorplan’ofahouse
Depictstheoveralllayoutofthesoftware
Derivedfromthreesources-
Informationabouttheapplicationdomain
Specificrequirementselements
Architecturalstylesandpatterns

7. INTERFACE DESIGN
Tellshowinformationflowsintoandoutofthe
systemandhowitiscommunicatedamongthe
componentsdefinedaspartofthearchitecture
Includestheuserinterface,externalinterfaces,and
internalinterfaces

8. COMPONENT -LEVEL DESIGN
Describestheinternaldetailofeachsoftware
componentbywayofdatastructuredefinitions,
algorithms,andinterfacespecifications

9. DEPLOYMENT -LEVEL DESIGN
Indicateshowsoftwarefunctionalityand
subsystemswillbeallocatedwithinthephysical
computingenvironmentthatwillsupportthe
software

10. EVOCATION

11. ARCHITECTURAL
DESIGN

12. SOFTWARE ARCHITECTURE
Thesoftwarearchitectureofaprogramorcomputing
systemistheoverallstructureofthesystemwhich
comprise
Thesoftwarecomponents
Theexternallyvisiblepropertiesofthosecomponents
Therelationshipsamongthecomponents
Constitutesarelativelysmall,intellectuallygraspable
modelofhowthesystemisstructuredandhowits
componentsworktogether.

13. ARCHITECTURAL DESIGN
STEPS
1)Represent the system in context
2)Define archetypes
3)Refine the architecture into components
4)Describe instantiations of the system

14. 1. REPRESENT THE SYSTEM IN
CONTEXT
Usesanarchitecturalcontextdiagram(ACD)that
modelsthemannerinwhichsoftwareinteractswith
entitiesexternaltoitsboundaries

15. 1. REPRESENT THE SYSTEM IN
CONTEXT
AnACDidentifiessystemsthatinteroperatewiththetargetsystem
(systemforwhicharchitecturaldesignistobedeveloped.
Super-ordinatesystems
Usetargetsystemaspartofsomehigherlevelprocessing
scheme
Sub-ordinatesystems
Usedbytargetsystemandprovidenecessarydataor
processingdetails
Peer-levelsystems
Interactonapeer-to-peerbasiswithtargetsystemto
produceorconsumedata
Actors
Peopleordevicesthatinteractwithtargetsystemtoproduce
orconsumedata

16. 1. REPRESENT THE SYSTEM IN
CONTEXT
Target system
I/F I/F
I/F I/F I/F
Actors
Peers
"Super"ordinate systems
"Sub"ordinate systems
Used by
Produces or
consumesProduces or
consumes
Depends on
Uses

17. 2. DEFINE ARCHETYPES
Anarchetypeisaclassorpatternthatrepresentsa
coreabstractionthatiscriticaltothedesignofan
architectureforthetargetsystem
Ingeneral,asmallsetofarchetypesisrequiredto
designevenrelativelycomplexsystems.
Thetargetsystemarchitectureiscomposedofthese
archetypes,whichrepresentstableelementsofthe
architecturebutmaybeinstantiatedindifferentways
basedonthebehaviorofthesystem
Thearchetypesandtheirrelationshipscanbe
illustratedusingUMLdiagrams

18. EXAMPLES
Archetypes in Software Example Architecture –
Node
Detector/Sensor
Indicator
ControllerFigure 10.7 UML relationships for SafeHome security function archetypes
(adapted from [BOS00])
Controller
Node
communicates with
Detector Indicator

19. 3. REFINE THE ARCHITECTURE
INTO COMPONENTS
Basedonthearchetypes,thearchitecturaldesignerrefinethe
softwarearchitectureintocomponentstoillustratetheoverall
structureandarchitecturalstyleofthesystem
Thesecomponentsarederivedfromvarioussources
Theapplicationdomainprovidesapplicationcomponents,
whichrepresenttheentitiesintherealworld
Theinfrastructuredomainprovidesdesigncomponents(i.e.,
designclasses)thatenableapplicationcomponentsbuthaveno
businessconnection
TheinterfacesintheACDimplyoneormorespecialized
componentsthatprocessthedatathatflowacrosstheinterface
AnUMLclassdiagramcanrepresenttheclassesoftherefined
architectureandtheirrelationships

20. COMPONENT STRUCTURESafeHome
Executive
External
Communication
Management
GUI Internet
Interface
Function
selection
Security Surveillance
Home
management
Control
panel
processing
detector
management
alarm
processing

21. 4. DESCRIBE INSTANTIATIONS OF
THE SYSTEM
Anactualinstantiationofthearchitectureis
developedbyapplyingittoaspecificproblem
Thisdemonstratesthatthearchitecturalstructure,
styleandcomponentsareappropriate
AnUMLcomponentdiagramcanbeusedto
representthisinstantiation

22. INSTANTIATIONS OF THE SYSTEMsensor
sensor
sensor
sensor
sensor
sensor
sensor
sensor
External
Communication
Management
GUI Internet
Interface
Security
Control
panel
processing
detector
management
alarm
processing
Keypad
processing
CP display
functions
scheduler
sensor
sensor
sensor
sensor
phone
communication
alarm
SafeHome
Executive

23. MIND MAP

24. SUMMARY
•The Design Model
–Dimensions
•Process Dimension
•Abstraction Dimension
–Data design elements
•Data architecting
–Architectural design elements
–Interface design elements
•User Interfaces
•External Interfaces
•Internal Interfaces
–Component-level design elements
–Deployment-level design elements

25. •Architectural Design
–Representing the System in Context
–Defining Archetypes
–Refining the Architecture into Components
–Describing Instantiations of the System