Unified Modeling Language (UML)mqhuang/courses/3513/f2012/... · UML is the de facto modeling language in software engineering Created and managed by the Object Management Group,

Introduction Use Case Diagram Class Diagram Sequence Diagram

Unified Modeling Language (UML)

Miaoqing HuangUniversity of Arkansas

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Outline

1 Introduction

2 Use Case Diagram

3 Class Diagram

4 Sequence Diagram

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Outline

1 Introduction

2 Use Case Diagram

3 Class Diagram

4 Sequence Diagram

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What is UML?

UML is a modeling languageA model is an abstraction describing a systemModeling language is used to express design

Use notation for depicting models

UML is the de facto modeling language in software engineeringCreated and managed by the Object Management Group, now atversion 2.4.1 (August 2011)Key persons: (three amigos) James Rumbaugh, Grady Booch,Ivar Jacobson

UML includes a set of graphical notation techniques to createvisual models of software-intensive systems

14 diagrams7 structural diagrams7 behavior diagrams

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UML Diagrams

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UML Diagrams – Example

use case diagram class diagram sequence diagram

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UML Diagrams – Example

Use case diagramDescribe the functional behavior of the system as seen by theuser

Class diagramDescribe the static structure of the system: Objects, attributes,associations

Sequence diagramDescribe the dynamic behavior between objects of the system

State machine diagramDescribe the dynamic behavior of an individual object

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UML Core Conventions

All UML Diagrams denote graphs of nodes and edgesNodes are entities and drawn as rectangles or ovalsRectangles denote classes or instances

Ovals denote functionsNames of Classes are not underlined

SimpleWatchFirefighter

Names of Instances are underlinedmyWatch:SimpleWatchJoe:Firefighter

An edge between two nodes denotes a relationship between thecorresponding entities

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Use Case Diagram

Use case diagrams represent the functionality of the systemfrom user’s point of view

WatchUser

Actor

Use case

ReadTime

SetTime

ChangeBattery

WatchRepairPerson

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Class Diagram

Class diagrams represent the structure of the system

12

push()release()

1

1

blinkIdxblinkSeconds()blinkMinutes()blinkHours()stopBlinking()referesh()

LCDDisplay BatteryLoad

1

2

1

TimeNow

1

Watch

Operations

statePushButton

Attribute

ClassAssociation

Multiplicity

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Sequence Diagram

Sequence diagrams represent the behavior of a system asmessages (“interactions”) between different objects

Message

:Time:Watch:WatchUser

Object

Activation

Actor

pressButton1()

Lifeline

blinkHours()

pressButton2()incrementMinutes()

:LCDDisplay

pressButton1and2()commitNewTime()

stopBlinking()

refresh()

pressButton1()blinkMinutes()

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State Machine Diagram

State machine diagrams represents behavior of a single objectwith interesting dynamic behavior

State

Initial state

Final state

Transition

Event

button1&2Pressed

button1Pressed

button2Pressed

button2Pressed

button2Pressed

button1Pressed

button1&2Pressed IncrementMinutes

IncrementHours

BlinkHours

BlinkSeconds

BlinkMinutes

IncrementSeconds

StopBlinking

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Outline

1 Introduction

2 Use Case Diagram

3 Class Diagram

4 Sequence Diagram

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What is a use case?

ScenarioA sequence of steps describing an interaction between a user anda system

The customer browse the catalog and adds desired items to the shoppingbasket. When the customer wishes to pay, the customer describes theshipping and credit information and confirms the sale. The systemchecks the authorization on the credit card and confirms the sale bothimmediately and with a follow-up email.

Use caseA use case is a set of scenarios tied together by a common usergoal

Buy a Product use case: a successful purchase or authorizationfailure

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Describe a use case

A set of scenarios in the Use Case “Buy a product online”:1. Customer browses through catalog and selects items to buy2. Customer goes to check out3. Customer fills in shipping information4. System presents full pricing information, including shipping5. Customer fills in credit card information6. System authorizes purchase7. System confirms sale immediately8. System sends confirming email to customer

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An Example

uc Use Cases

System Boundary

OrderFood

CookFood

OrderWine

ServeFood

ServeWine

EatFood

DrinkWine

Pay forFood

Pay forWine

Waiter

Chef

Client

Cashier

receive order

confirm order

facilitate payment

pay

accept

payment

place order

<<extend>> {if wine was ordered}

<<extend>>

<<extend>>

{if wine was

served}

<<extend>>{if wine

was consumed}

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Actor and Use Case

An actor is a role that a user play with respect to thesystemActors are connected to the use cases by a line

A single actor may perform many use casesA use case may have several actors performing it

Four types of relationships in use case diagramGeneralization between use casesGeneralization between actorsInclude relationship between use casesExtend relationship between use cases

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Generalization between use cases

Different versions of a use case share some actions in commonand have some that are unique to each one

Generalized use case: abstract use caseIt may never exist in a real system

Specialized use case: concrete use case

Pay utility bill

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Generalization between Actors

Specialized actor can do everything the generalactor can do, and more

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Include Relationship between Use Cases

One use case includes the functionality of another use caseInvocation of one use case by another one

e.g., calling a function or invoking an operation within source code

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Extend Relationship between Use Cases

One use case may be extended by the functionality in anotheruse case

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Include, Generalization, Extend

IncludeUse include when you are repeating yourself in two or moreseparate use cases and you want to avoid repetition

GeneralizationUse Generalization when you are describing a variation on normalbehavior and you wish to describe it casually

ExtendUse extend when you are describing a variation on normalbehavior and you wish to use the more controlled form, declaringyour extension points in your base use case

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Outline

1 Introduction

2 Use Case Diagram

3 Class Diagram

4 Sequence Diagram

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Class Diagram

Class diagrams show the static structure of the classes thatmake up a system or subsystemUse case diagrams show the functional requirements of a system(or subsystem) from the perspective of the end-user of a system

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Classes

Classes are shown as rectanglesClass nameOther compartments

AttributesOperationsOther predefined compartments

Name conventionClass’ name

Have no space between multiple wordsCapitalize the first letter in eachsubsequent world

Name of features in compartmentsHave no space between multiple wordsCapitalize the first letter in eachsubsequent world except the first world

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Associations among classesAssociations represent relationships between(instances of) classes

Classes collaborate with each other by passingmessages and receiving responses

Association nameIndicates the nature of the associationAssociate name should begin with a capital letterNavigability: use arrow to indicate how to interpretthe association

Unidirectional associationBidirectional association: without arrow

Role nameIndicate the role played by a class in anassociationAttached to the corresponding association endCan use the same rule of naming features to namethe role, i.e., low case the very first letter andcapitalize the first letter of subsequent word

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Multiplicity

Multiplicity indicates how many objects may participate in thegiven relationship (during the run-time of your software system)

*: 0..infinity1: 1..1n..m: low_bound..up_bound

Multiplicity of an association end is not shownThe multiplicity is not knownThe multiplicity is not specified

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Aggregation

Aggregation symbol.Assembly consists of components.Component is part of an assembly

Aggregation associationAn instance of one class may consist of instances of another classwhole-part association

whole is made up of partsUse a solid line with an unfilled diamond shape at the end

Diamond is connected to the class that is the aggregateA part is capable of existing outside of whole-part association

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Composition

Document

SectionFrontMatter Index1 0..1

0..11..*

1..*

Document

FrontMatter [1]

Section [1..*]

Index [0..1]0..1

1..*

Composition associationwhole-part association

The life-cycle of the ‘part’ cannot extend beyond the life-cycle of the‘whole’

Two different notationsFilled diamond notationGraphical containment

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Generalization

Generalization relationship is(sometimes) described as being a kindof relationship

Generalized class: superclass(supertype)Specialization: subclass (subtype)

Generalization allows the inheritance ofthe attributes and operations of asuperclass by its subclasses

Subclass can override the operations inthe superclass

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More on attribute and operation

Attribute and Operation Typesfeature-name : type

Attribute and Operation Visibilityprivate (-)

The feature is available only within the class that owns the featurepublic (+)

The feature is available to any class associated with the class thatowns the feature

protected (#)The feature is available within the class that owns that feature andany subtype of that class

package (∼)The feature is available only to other classes in the same package

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Outline

1 Introduction

2 Use Case Diagram

3 Class Diagram

4 Sequence Diagram

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Purpose of Sequence Diagram

Static diagramUse case diagrams show the static relationship between actorsand use casesClass diagrams show the static relationship between classes orinstances

A program is a sequence of interactions among objects (i.e.,instances of classes)

Difficult to understand a program only with static diagramsPurpose of sequence diagram

Model the high-level interactions between active objects in asystemModel the high-level interactions between subsystems

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Sequence Diagram Example

:Journeyfirst:CarSharer

:SharingAgreement

:RecordAgreementControl

:RecordAgreementUI

CarMatchAdministrator

new agreementdetails set create sharing

agreement

get car sharer ID

find by ID

get journey ID

find by ID

add journey set sharingagreement

set first arranged

loop [i=1..no of car sharers]

sd Create new agreement

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NotationFrame


:SharingAgreement


:RecordAgreementUI



agreement

get car sharer ID

find by ID

get journey ID

find by ID


set first arranged



Sequence diagrams aredrawn in frames

New in UML 2.0

Time runs verticallyLifelines are arrangedhorizontally

Represent object instances

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NotationFrame


:SharingAgreement


:RecordAgreementUI



agreement

get car sharer ID

find by ID

get journey ID

find by ID


set first arranged



Sequence diagrams aredrawn in frames

New in UML 2.0

Time runs verticallyLifelines are arrangedhorizontally

Represent object instances

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NotationLifeline

Participating instances are represented bylifelines

Dashed vertical lineRectangle representing an object

Syntax Explanationo An object named oo : C An object named o of class C:C An anonymous object of class C

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NotationMessages and Activation box

A message is shown using an arrow going from the sender to thereceiver

Different types of messagesSynchronous

The sender waits until the reply is receivedAsynchronous

The sender does not wait for the reply; instead, it carries on the nextstep in its own sequence

CreationA message causes the creation of an object instance to which themessage is sent

Reply

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NotationMessages and Activation box

A message is shown using an arrow going from the sender to thereceiverDifferent types of messages

SynchronousThe sender waits until the reply is received

AsynchronousThe sender does not wait for the reply; instead, it carries on the nextstep in its own sequence

CreationA message causes the creation of an object instance to which themessage is sent

Reply

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Sequence Diagram Example with Explicit Reply


:SharingAgreement


:RecordAgreementUI



agreement

get car sharer ID

find by ID

get journey ID

find by ID


set first arranged



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NotationCombined Fragments

A sequence of messages can be combined into a fragmentLoop, branches, ...


:SharingAgreement


:RecordAgreementUI



agreement

get car sharer ID

find by ID

get journey ID

find by ID


set first arranged



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NotationCombined Fragments

:ReliableDistributor:Order

dispatch

loop [ for each item ]

:NormalDistributor

dispatch

alt [ value > $10,000 ]

[ else ]

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Exercise

Lay out the lifelines for instances of the classes Student, EnrollInSeminar,SecurityLogon, StudentDatabase, and Seminar. Add the followingmessages to the diagram. Note, keep the order of the messages.

1 Request to enroll to seminar A2 Create an instance of SecurityLogon class3 Provide name4 Provide student number5 Provide password6 Verify the student (name, number, password)7 Return verification result8 Return the student information9 Add the student into the seminar A10 Confirmation of enrollment of seminar A11 Display the confirmation to student

Note: EnrollInSeminar class is both the main control and the main interfacewith the student

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Unified Modeling Language (UML)mqhuang/courses/3513/f2012/... · UML is the de facto modeling language in software engineering Created and managed by the Object Management Group,

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