Introduction to OOA and UML

In this Business Analysis training session, you will learn about Introduction to OOA and UML. Topics covered in this session are:
• Elements, purpose and example of UML Diagrams :
• Use Case Diagram
• Class Diagram
• Sequence Diagram
• Collaboration Diagram
• State Diagram
• Activity Diagram
For more information, click here: https://www.mindsmapped.com/courses/business-analysis/become-a-business-analyst-with-hands-on-practice/

1. Business Analysis
Training
Introduction to OOA and UML

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Agenda
•Elements, purpose and example of UML Diagrams :
•Use Case Diagram
•Class Diagram
•Sequence Diagram
•Collaboration Diagram
•State Diagram
•Activity Diagram

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Introduction

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Why Do We Need Object Oriented
Analysis or a Structured Analysis?

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Stated vs Un-Stated

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Another Example

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Software Projects (2012 Report)
Waterfall
Successful
Challenged
Failed
Agile
Successf
ul
Challeng
ed
Failed
Source: Standish Chaos Report (2012)
How Successful are Our Projects?

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Where does it go wrong?

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Software Analysis and Design

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Modeling
•Describing a system at a high level of abstraction
–A model of the system
–Used for requirements and specifications
•Is it necessary to model software systems?

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What is UML?
•UMLstandsfor“UnifiedModelingLanguage”
•Itisaindustry-standardgraphicallanguageforspecifying,visualizing,
constructing,anddocumentingtheartifactsofsoftwaresystems
•TheUMLusesmostlygraphicalnotationstoexpresstheOOanalysisand
designofsoftwareprojects.
•Simplifiesthecomplexprocessofsoftwaredesign

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Why UML for Modeling
•Usegraphicalnotationtocommunicatemoreclearlythannatural
language(imprecise)andcode(toodetailed).
•Helpacquireanoverallviewofasystem.
•UMLisnotdependentonanyonelanguageortechnology.
•UMLmovesusfromfragmentationtostandardization.

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Overview of UML Diagrams
OverviewofUMLDiagrams
Structural
: element of spec. irrespective of time
oClass
oComponent
oDeployment
oObject
oComposite structure
oPackage
Behavioral
: behavioral features of a system / business
process
oActivity
oState machine
oUse case
oInteraction
Interaction
: emphasize object interaction
oCommunication(collaborati
on)
oSequence
oInteraction overview
oTiming

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Types of UML Diagrams
•Use Case Diagram
•Class Diagram
•Sequence Diagram
•Collaboration Diagram
•State Diagram
This is only a subset of diagrams … but are most widely used

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Use Case Diagram
•Usedfordescribingasetofuserscenarios
•Mainlyusedforcapturinguserrequirements
•Worklikeacontractbetweenenduserandsoftwaredevelopers

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Use Case Diagram (core components)
Actors:Arolethatauserplayswithrespecttothesystem,includinghuman
usersandothersystems.e.g.,inanimatephysicalobjects(e.g.robot);an
externalsystemthatneedssomeinformationfromthecurrentsystem.
Usecase:Asetofscenariosthatdescribinganinteractionbetweenauser
andasystem,includingalternatives.
Systemboundary:rectanglediagramrepresentingtheboundarybetween
theactorsandthesystem.

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Use Case Diagram (core relationship)
Association:communicationbetweenanactorandausecase;
Representedbyasolidline.
Generalization:relationshipbetweenonegeneralusecaseanda
specialusecase(usedfordefiningspecialalternatives)
Representedbyalinewithatriangulararrowheadtowardtheparent
usecase.

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Generalization

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Use Case Diagram (core relationship)
Include:adottedlinelabeled<<include>>beginningatbaseusecaseand
endingwithanarrowspointingtotheincludeusecase.Theinclude
relationshipoccurswhenachunkofbehaviorissimilaracrossmorethanone
usecase.Use“include”insteadofcopyingthedescriptionofthatbehavior.
<<include>>
Extend:adottedlinelabeled<<extend>>withanarrowtowardthebasecase.
Theextendingusecasemayaddbehaviortothebaseusecase.Thebaseclass
declares“extensionpoints”.
<<extend>>

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Use Case Diagram (core relationship)

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Use Case Diagram (core relationship)

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Use Case Diagrams
Library System
Borrow
Order Title
Fine Remittance
Client
Employee
Supervisor
Boundary
Actor
Use Case

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Use Case Diagrams

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Types of Actor
Actors
Primary
Actor
Secondary Actor

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Types of Actor

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Exercise

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Use Case Specification

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Exercise

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Use Cases for the Exercise

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Actors for the Exercise

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Relationship between the actors

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•Usedfordescribingstructureandbehaviorintheusecases
•Provideaconceptualmodelofthesystemintermsofentitiesandtheir
relationships
•Usedforrequirementcapture,end-userinteraction
•Detailedclassdiagramsareusedfordevelopers
Class diagram

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A collection of similar objects is a class. And an object is an instance of a class.
What is a Class?

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Class representation
•Eachclassisrepresentedbyarectanglesubdividedintothree
compartments
•Name
•Attributes
•Operations
•Modifiersareusedtoindicatevisibilityofattributesandoperations.
•‘+’isusedtodenotePublicvisibility(everyone)
•‘#’isusedtodenoteProtectedvisibility(friendsandderived)
•‘-’isusedtodenotePrivatevisibility(noone)
•Bydefault,attributesarehiddenandoperationsarevisible.

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An example of Class
Account_Name
-Customer_Name
-Balance
+addFunds( )
+withDraw( )
+transfer( )
Name
Attributes
Operations

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•Super Class
•Parent Class
•Generalized Class
•Specialized Class
•Sub Class
•Child Class
Types of Classes

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Animal
Amphibian
Mammal
Reptile
Horse
Example
Child Class
of Animal
Child Class
of Animal
Child Class
of Mammal
Super Class
of horse
Parent Class
of Mammal
Sub Class of
Animal

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OO Relationships
•TherearetwokindsofRelationships
•Generalization(parent-childrelationship)
•Association(oneobjecttoanotherobjectrelationship)
•Associationscanbefurtherclassifiedas
•Aggregation
•Composition

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OO Relationships : Generalization
Subtype2
Supertype
Subtype1
•Generalizationexpressesa
parent/childrelationship
amongrelatedclasses.
•Usedforabstractingdetailsin
severallayers
Regular
Customer
Loyalty
Customer
Customer
Example
:
Regular
Customer
Loyalty
Customer
Customeror:

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OO Relationships : Association
•Represent relationship between instances of classes
•Student enrolls in a course
•Courses have students
•Courses have exams
•Etc.
•Association has two ends
•Role names (e.g. enrolls)
•Multiplicity (e.g. One course can have many students)
•Navigability (unidirectional, bidirectional)

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University Person
1
0..1
*
*
Multiplicity
Symbol Meaning
1 One and only one
0..1 Zero or one
M..N From M to N (natural language)
* From zero to any positive integer
0..* From zero to any positive integer
1..* From one to any positive integer
teacheremployee
Role
“A given university groups many people;
some act as students, others as teachers.
A given student belongs to a single
university; a given teacher may or may not
be working for the university at a particular
time.”
student
Association: Multiplicity and Roles

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Class Diagram

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OO Relationships : Composition
Class W
Class P
1
Class P
2
Whole Class
Part Classes
Automobile
Engine Transmission
Example
Composition:expressesarelationshipamonginstancesof
relatedclasses.ItisaspecifickindofWhole-Part
relationship.
Itexpressesarelationshipwhereaninstanceofthe
Whole-classhastheresponsibilitytocreateandinitialize
instancesofeachPart-class.
Itmayalsobeusedtoexpressarelationshipwhereinstances
ofthePart-classeshaveprivilegedaccessorvisibilityto
certainattributesand/orbehaviorsdefinedbytheWhole-
class.
Compositionshouldalsobeusedtoexpressrelationship
whereinstancesoftheWhole-classhaveexclusiveaccessto
andcontrolofinstancesofthePart-classes.
Compositionshouldbeusedtoexpressarelationshipwhere
thebehaviorofPartinstancesisundefinedwithoutbeing
relatedtoaninstanceoftheWhole.And,conversely,the
behavioroftheWholeisill-definedorincompleteifoneor
moreofthePartinstancesareundefined.
[From Dr.DavidA. Workman]

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OO Relationships : Composition
[From Dr.DavidA. orkman]
Class C
Class E
1
Class E
2
AGGREGATION
Container Class
ContaineeClasses
Bag
Apples Milk
Example
Aggregation:expressesarelationshipamong
instancesofrelatedclasses.Itisaspecifickindof
Container-Containeerelationship.
Itexpressesarelationshipwhereaninstanceof
theContainer-classhastheresponsibilitytohold
andmaintaininstancesofeachContainee-class
thathavebeencreatedoutsidetheauspicesofthe
Containerclass.
Aggregationshouldbeusedtoexpressamore
informalrelationshipthancompositionexpresses.
Thatis,itisanappropriaterelationshipwherethe
ContaineranditsContaineescanbemanipulated
independently.
AggregationisappropriatewhenContainerand
Containeeshavenospecialaccessprivilegesto
eachother.

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Aggregations vs. Composition
•Compositionisreallyastrongformofaggregation
•componentshaveonlyoneowner
•componentscannotexistindependentoftheir
owner
•componentsliveordiewiththeirowner
e.g.Eachcarhasanenginethatcannotbe
sharedwithothercars.
•Aggregationsmayform"partof"theaggregate,butmaynotbe
essentialtoit.Theymayalsoexistindependentoftheaggregate.
e.g.Applesmayexistindependentofthebag.

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Interaction Diagrams
A Sequence diagram is an interaction diagram that shows how objects
operate with one another and in what order.
•They're also called event diagrams.
•A sequence diagram is a good way to visualize and validate various
runtime scenarios.
•These can help to predict how a system will behave and to discover
responsibilities a class may need to have in the process of
modeling a new system

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Sequence Diagrams

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Class Roles or Participants
Class roles describe the way an object will behave in context. Use the UML
object symbol to illustrate class roles, but don't list object attributes.
Basic Sequence Diagram Symbols and Notations

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Basic Sequence Diagram Symbols and Notations
Activation or Execution Occurrence
Activation boxes represent the time an object needs to complete a task.
When an object is busy executing a process or waiting for a reply message,
use a thin gray rectangle placed vertically on its lifeline.

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Basic Sequence Diagram Symbols and Notations
Messages
Messages are arrows that represent communication between objects. Use
half-arrowed lines to represent asynchronous messages. Asynchronous
messages are sent from an object that will not wait for a response from the
receiver before continuing its tasks..

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Basic Sequence Diagram Symbols and Notations
Lifelines
Lifelines are vertical dashed lines that indicate the object's presence over
time.

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Basic Sequence Diagram Symbols and Notations
Destroying Objects
Objects can be terminated early using an arrow labeled "<< destroy >>" that
points to an X. This object is removed from memory. When that object's
lifeline ends, you can place an X at the end of its lifeline to denote a
destruction occurrence.
Loops
A repetition or loop within a sequence diagram is depicted as a rectangle.
Place the condition for exiting the loop at the bottom left corner in square
brackets [ ].

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Types of Messages in Sequence Diagram
Synchronous Message
A synchronous message requires a response before the interaction can
continue. It's usually drawn using a line with a solid arrowhead pointing
from one object to another.

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Types of Messages in Sequence Diagram
Asynchronous Message
Asynchronous messages don't need a reply for interaction to continue. Like
synchronous messages, they are drawn with an arrow connecting two
lifelines; however, the arrowhead is usually open and there's no return
message depicted.

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Types of Messages in Sequence Diagram

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Types of Messages in Sequence Diagram

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Types of Messages in Sequence Diagram

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Types of Messages in Sequence Diagram

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Caller Phone Recipient
Picks up
Dial tone
Dial
Ring notification Ring
Picks up
Hello
Sequence Diagram (make a phone call)

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Sequence Diagram : Object interaction
Self-Call:Amessagethatan
Objectsendstoitself.
Condition:indicateswhena
messageissent.Themessageis
sentonlyiftheconditionistrue.
Iteration
Condition
A B
Synchronous
Asynchronous
Transmission
delayed
Self-Call
[condition]
remove()
*[for each]
remove()

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Sequence Diagrams –Object Life Spans
•Creation
•Create message
•Object life starts at that point
•Activation
•Symbolized by rectangular stripes
•Place on the lifeline where object is
activated.
•Rectangle also denotes when object
is deactivated.
•Deletion
•Placing an ‘X’ on lifeline
•Object’s life ends at that point
Activation
bar
A
B
Create
X
Deletion
Return
Lifeline

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Sequence Diagrams –Example

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The second interaction diagram is collaboration diagram. It shows the
object organization. Here in collaboration diagram the method call
sequence is indicated by some numbering technique.
Collaboration Diagrams

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Collaboration Diagram : Example

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•Showstherelationshipbetweenobjectsandtheorderofmessagespassed
betweenhem.
•Theobjectsarelistedasrectanglesandarrowsindicatethemessagesbeing
passed
•Thenumbersnexttothemessagesarecalledsequencenumbers.They
showthesequenceofthemessagesastheyarepassedbetweentheobjects.
•Conveythesameinformationassequencediagrams,butfocusonobject
rolesinsteadofthetimesequence.
Interaction Diagrams : Collaboration diagrams

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State Diagrams: (Billing Example)
StateDiagramsshowthesequencesofstatesanobjectgoesthroughduring
itslifecycleinresponsetostimuli,togetherwithitsresponsesandactions;
anabstractionofallpossiblebehaviors.
Unpaid
Start
End
Paid
Invoice created paying Invoice destroying

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State Diagrams: (Traffic light example)
Yellow
Red
Green
Traffic Light
State
Transition
Event
Star
t

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Activity Diagram
Overview
•Activity diagram is another important diagram in UML to describe dynamic
aspects of the system.
•Activity diagram is basically a flow chart to represent the flow form one
activity to another activity. The activity can be described as an operation of
the system.
•So the control flow is drawn from one operation to another. This flow can
be sequential, branched or concurrent. Activity diagrams deals with all type
of flow control by using different elements like fork, join etc.

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Purpose of an Activity Diagram
•Draw the activity flow of a system.
•Describe the sequence from one activity to another.
•Describe the parallel, branched and concurrent flow of the system.

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Elements of Activity Diagram

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Activity Diagram : Example

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Activity Diagram : Example

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•Agile Methodology
•User Story –Introduction
•Format of User Story
•Usage of User Story
•Example of User Story
Topics to be covered in next session

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Thank you