ict117 week03 oo and uml s

8/6/2019 ICT117 Week03 OO and UML s

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Object-OrientationUML

PowerPoint Presentation for Dennis, Wixom, & Tegarden Systems Analysis and Design with UML, 3rd EditionCopyright 2009 John Wiley & Sons, Inc. All rights reserved.


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What is an object?Something identifiableSomething with attributesSomething able to do things (behaviour)And has meaning to people in its context

17 March, 2011 ICT117 Systems Analysis & Design, Semester 2, 2010

Includes John Wiley& Sons Inc material

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Abstraction and objectsObject is an abstraction of somethingIn business, objects can be described

CustomerProduct

Order

Delivery

The Information System that is an abstractionof the business can be composed ofinteracting objects



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Characteristics of objectsObjects can be classified on the basis ofsimilarities



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Characteristics of objectsSimilarly classified objects may be furtherspecialised (or generalised)



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AbstractionA class is an abstraction of the objects that itdescribesA class is NOT a collection of all objectsA class is a TEMPLATE that applies to all itsobjects



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CLOCK: Tells time of day

Has two handsHas numerals

Circular display format


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InheritanceGeneralisation and specialisation representan inheritance hierarchy



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Living Thing

Animal Vegetable

FishMammal


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PolymorphismMeans (literally) one thing that has many formsor shapesIn Object-Orientation it applies to inheritancehierarchies.It means: a classs particular inheritedbehaviour being changeable depending onthe identity of the sub-class



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PolymorphismThe class Animal will have a behaviour Movethat is inherited by its sub-classes.When Mammal receives a message to Move, itwill walk, but Fish receiving the samemessage will swim



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Animal

FishMammal


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EncapsulationTo put something inside something else(hiding something)The concept that we dont need to know howsomething is done just that it is done.In Object terms we can know the name of abehaviour in order to execute it, but wedont know how it is executed.



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Encapsulation



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From Booch,Maksimchuk et al pg 51


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Software objectsThe business objects that we identify in theProblem Domain can become:Software objects in the Solution Domain

Software that is identifiable (named modules)

Software that has attributes (data structures)

Software that has behaviour (executes logical sequences)

We construct an IS from software objects tosupport the business17 March, 2011 ICT117 Systems Analysis & Design, Semester 1, 2011


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The Unified Modeling

Language


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Unified Modeling LanguageUML provides a common vocabulary of object-oriented terms and diagramming techniquesrich enough to model any systemsdevelopment project from analysis throughto implementation

Version 2.0 has 14 diagram types in 2 majorgroups:Structure diagrams

Behaviour diagrams


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Basic concepts (Booch et al, 2007)Object:A well-defined conceptCan be comprehended intellectuallyUniquely identifiableRepresents some part of realityCan be real (tangible) or abstractHas a well-defined role in the problemdomain


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Basic concepts (Booch et al, 2007)Object definition for OOSAD purposes:

An entity that has state, behaviour andidentity. The structure and behaviour ofsimilar objects are defined in theircommon class. The terms instance andobject are interchangeable.

Class is a generalisation of (or classificationof) a set of like objects


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State, behaviour, identityState: all the properties of an object plus theircurrent valuesBehaviour: an objects outwardly visibleactivity how it acts and reacts in terms ofits state and its stimuli (communications)Identity: that property of an object thatdistinguishes it from all other objects

(Booch et al, 2007)


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UML Structure DiagramsRepresent the data and static relationships inan information systemClassObject

Package

Deployment

ComponentComposite structure


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UML Behaviour DiagramsDepict the dynamic relationships among theinstances or objects that represent thebusiness information system- Activity - Timing

- Sequence - Behaviour state machine

- Communication - Protocol state machine

- Interaction overview - Use Case diagrams


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SummaryThe Unified Process is a two-dimensionalsystems development process describedwith a set of phases and workflowsThe Unified Modeling Language, or UML, is astandard set of diagramming techniques


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OOSADUse case drivenArchitecture centricIterative and incremental



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The Unified Process

A variant of the SDLC using Object-

Oriented modelling techniques


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The Unified ProcessA specific methodology that maps out whenand how to use the various UML techniquesfor object-oriented analysis and designA two-dimensional process consisting ofphases and workflows

Phases describe how the system evolves overtime Workflows are collections of tasks that occurthroughout the lifecycle, but vary in intensity


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The Unified ProcessWorkflows


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Unified Process PhasesInceptionElaborationConstructionTransition


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Engineering WorkflowsBusiness modelingRequirements (gathering)AnalysisDesignImplementationTestingDeployment


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Supporting WorkflowsProject managementConfiguration and change managementEnvironmentOperations and support*Infrastructure management*

* Part of the enhanced unified process


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Next weekRequirements determination(finding out what is required to be done)



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ict117 week03 oo and uml s

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