seem4570 system design and implementationseem4570/2017/lecture/lecture10.pdf · 2017. 10. 31. ·...

SEEM4570 System Design and Implementation

Lecture 10 – UML

Introduction

• In the previous lecture, we talked about software development life cycle in a “conceptual level”• E.g. we need to write documents, diagrams, etc. But how to

write/draw them?

© 2017. Gabriel Fung. 2

UML (1)

• Unified Modeling Language (UML) is a standardized general-purpose modeling language in the field of object-oriented software engineering. • The standard is managed, and was created, by OMG.

• OMG – Object Management Group – a consortium. • UML provides specifications but not implementation.

• Before a specification can be accepted as a standard by OMG, the team which propose the specification must guarantee they can use the specification to bring a product to a market within 1 year. • This prevents un-implementable standard.

• UML was in the list of OMG adopted technologies in 1997, and also the industry standard for modeling software-intensive systems.


Side Track: About Consortium

• A consortium is an association of two or more individuals, companies, organizations or governments (or any combination of these entities) with the objective of participating in a common activity or pooling their resources for achieving a common goal.• Consortium is a Latin word, meaning "partnership",

"association" or "society"• Con = "together"• Sors = "fate"• Consors = "Partner"


UML (2)

• UML is used to specify, visualize, modify, construct and document the artifacts of an object-oriented software-intensive system. • UML offers a standard way to visualize a system's

blueprint.• It can be used with all processes, throughout the

software development life cycle, and across different implementation technologies.


UML (3)

• Current version is UML 2.4• It has 14 types of diagrams divided into two categories• Each category represents a different view of a model

(discuss in the next two slides)


Structure Diagrams

• Emphasize the things that must be presented in the system.• Used extensively in documenting the software architecture

• Programmers will find them very useful in writing programs

• Diagrams:• Class diagram• Object diagram• Package diagram• Component diagram• Composite structure diagram• Profile diagram• Deployment diagram


Behavior Diagrams• Emphasize what must be happened in the system. • Used extensively to describe the functionality of the system• System managers and other non-programmers may find

them useful in explaining the system• Diagrams:• Activity diagram• UML state machine diagram• Use case diagram• Communication diagram (a kind of interaction diagram)• Interaction overview diagram (a kind of interaction

diagram)• Sequence diagram (a kind of interaction diagram)• Timing diagram (a kind of interaction diagram)


Class Diagram – Overview

• Describes the structure of a system by showing the system's classes, attributes, and relationships among classes• In a class diagram, there are many classes. Each class

is represented by a box with three parts:• Top: The name of the class• Middle: The properties/attributes of

the class• Bottom: The methods of the class


Person# name:string– age:int

+setName(name:string)+getName()+setAge(age: int)+getAge()

#,+,– areknownas“visibility”(Seenextslide)

Class Diagram – Drawing

• Visibility – used to specify the visibility of the attributes and methods (not mandatory, but usually has)• + Public • – Private • # Protected

• Relationship – define the logical relationship among classes• Major relationships: Bi-directional, Uni-directional,

Aggregation, Reflexive, Generalization, Realization


Bi-Directional Relationship


Room– location:String– room:int

+setLocation(name:String)+getLocation():

Course– name:string– code: string

+setName(name:string)+getName():

0..* 0..1

Aclassroomcanbeassignedto0tomanycourses

Acoursecanbeassignedto0or1classroom

ItiscalledMultiplicity

Multiplicity Meaning

x..y xtoy(x≥0,y>0),e.g.0..1,0..2,2..6,…

x..* xor more

* Zero ormore

n nonly, e.g.1,4,10,…

assignedassigned

Uni-Directional Relationship


Course– courseCode:String– description: String:

+setName(name:String)+getName():

Printer– printerID:String:

+setJob(courseCode:String)+getName():

0..*print

Inauni-directionalassociation,twoclassesarerelated,butonlyoneclassknowsthattherelationshipexists.Inthisexample,onlythePrinterclassknowstheexistenceoftheCourseclass.Thismodelingallowsprintersknowwhichcoursestheyareprinting,butthecoursesdonotknowtheyarebeingprinted.Thisloosensthecouplingoftheobjectsandthereforemakesthe

systemmoreadaptivetochanges.

Uni-Directional Relationship (cont'd)


MyDB:+connect()+disconnect():

GameRecord::

GameStage1::

GameStage2::

Aggregation / Composition Relationship (1)


Building– securityGuard:Person[]:

:

1..*has

Person::

Note:Anon-filldiamondindicatestherelationshipis“weak”,i.e.evenifBuildingis“destroyed”,Person(i.e.securityguards)willnotbe“destroyed”.

Buildinghasanon-trivialclass"Person"!That’swhyweneedtolinkitback!



Room::

Building– listOfRoom:Room[]:

:

1..*has

Buildinghasanothernon-trivialclass!That’swhyweneedtolinkitback!

Note:Thediamondis“filled”,whichmeansRoomdependsonBuilding,i.e.iftheBuildingis“destroyed”,thenallRoomswillalsobe“destroyed”.Thistypeof“strongaggregation”iscalledComposition


• If necessary, we can have uni-directional relationship for aggregation/composition relationship


B::

A::

B::

A::

Reflexive Relationship


Room# subRoom:Room:

Building#name:String#listOfRoom:Room[]

:

1..*has

0..*contains

Aroomcontainssomerooms,e.g.RM101containsRM101AandRM101B

Akindofreflexiverelationship.Again,itcanbebi-directionaloruni-directional

Staff::

1supervisor

0..*supervises

AstaffhasonesupervisorAstaffsupervises0ormanystaff

Generalization Relationship


Person# name:String:

+getName()

Student– studentID:String+getGPA()

Staff#salary:int+getOfficeLocation()

Professor– housingAllowance:int:

Admin Staff::

Generalizationrelationship

Realization Relationship (1)


<<interface>>Person

+getName()

Student– studentID:String+getName()

Staff#salary:int+getName()

Professor– housingAllowance:int:

Admin Staff::

Generalizationrelationship

RealizationrelationshipItshouldcontainsnothing

Canonlybe+or#

• What is realization?• Realization is one of the major properties of Object

Oriented (OO) modeling, it implements an interface.• Don’t confuse with GUI (graphical user interface). This interface did

nothing with GUI.• In OO Programming, if a class is defined as an interface, it

does not have any implementation detail.• Hence, we need to write the details that are defined in the interface

in the implementing classes.• In the diagram in the previous slide, we need to write the

“getName” method in the Student Class and Staff Class.• It is the responsibility of the program designer to drop down every

single implementation issue carefully and clearly in the diagram.


Realization Relationship (2)

Class Diagram Summary


Class A

Class B

Class A

Class B

Class A

Class B

Class A

Class B

Class A

Class B

Class A

Class B

Class A

Bi-Directional Uni-Directional

Reflexive

Aggregation Composition Realization Generalization

Object Diagram

• An object diagram in the Unified Modeling Language (UML), is a diagram that shows a complete or partial view of the structure of a modeled system at a specific time.• Remember the differences between Class and Object?

• Object diagrams are more concrete than class diagrams, and are often used to provide examples.• An Object diagram focuses on some particular set of object

instances and attributes, and the links between the instances.


Object Diagram Example


Room# floor:int:

Building#name:String#listOfRoom:Room[]

:

1..*has

ERM301 :RoomFloor:3

ERB :Buildingname=ERBlistOfRoom =Vector<Room>

has

ERM401 :RoomFloor:4has

ERM506 :RoomFloor:5has

Object Diagram – More Information

• Object diagrams help clarify classes and inheritance• They are useful to demonstrate what would happen in

the system at a specific time.• Can help non-programmers to understand more about the

system as they may find class diagrams are too abstract.• May help programmers as well!

• Unfortunately, UML 2.4 specification provides no definition of object diagram!• It does not have a concrete definition of how it should be

drawn!


Package Diagram

• Describes how a system is split up into logical groupings by showing the dependencies among these groupings.• Package is a namespace used to group together

elements that are semantically related and might change together. • Because package is a namespace, elements (e.g. programs)

inside the same package should have unique names. • A package can import/access/use other packages. • Package can also be merged with other packages.


Package Diagram (cont’d)

• For example, in a Java program:

• A package is rendered as a tabbed folder:


package webShoppingCart;

import basicWebComponent;import java.io.*;import ...:

public XXX extends GeneralShoppingCart{:

}

Thenameofthepackagethatwecreated

Weneedtoimportthesepackages

Wetrytogroupprogramsintopackagesforbetterresourcesmanagement.Sowealsoneedtotelltheprogrammershowtoimplementourideas!

WebShoppingCart

Notations• Import• A relationship that shows the model elements in a package

which are to be imported from another package and the visibility is public

• Access• A relationship that shows the model elements in a package

which are to be imported from another package and the visibility is private, i.e. other packages that merge/import it cannot access the packages it has accessed• Note that it may be impossible to implement.

• Merge• A relationship between two packages showing that their

contents are to be combined.


Package Diagram Example


WebShopping

MobileShopping

MailShopping

Inventory

<<import>>

package

ShoppingCartPayment

<<import>><<merge>><<merge>><<import>>

<< access>>

Utility

<<import>>

Component Diagram

• Describes how a software system is split up into components and shows the dependencies among these components.• Developers find the component diagram useful because it

provides them with a high-level, architectural view of the system• Although may not be able to implement the system (too

abstract), it helps developers formalizing a roadmap for the implementation, and make decisions about task assignments.

• System administrators find component diagrams useful because they get an early view of the logical software components that will be running on their systems.


Components


AComponent

Services/interfacetobeprovidedtoothercomponents

Services/interfacerequiredfromothercomponents

AComponent

Services/interfacetobeprovidedtoothercomponents

AComponent

Services/interfacerequiredfromothercomponents

Component Diagram Example


OrderProductServices Customer

Product

OrderProduct

CustomerDetail

ProductCode

Composite Structure Diagram

• Visualizes the internal structure of a class. • A kind of component diagram used in modeling a system

at micro point-of-view.• The key entities are:• Part

• A role played at runtime by an object or by a collection of objects• Port

• An interaction point that can be used to connect other parts or the environment.

• Connector• It binds entities together, allowing them to interact at runtime.

• Collaborator• Represents by dotted oval. An abstract idea.


Composite Structure Diagram Example


SearchEngine

Searchport

Searchbook

SearchCD

Requestport

RequestProduct

part

port

environment

AnotherService

connector

AportDoSth

OrderProductServices

Deployment Diagram

• Describes the hardware used in system implementations and the execution environments and artifacts (e.g. software) deployed on the hardware.


Note:ThisisnotUMLstandardcomponents(forillustrationpurposeonly)

Deployment Diagram Example


Use Case Diagram• Describe a set of actions (use cases) that some

systems should or can perform in collaboration with one or more external users (actors). • Each use case should provide some observable and

valuable result to the user of the system.• Used to specify what the system should do but not

how the system should do.• Major elements of the use case diagram are:• Actor• Association / Relationship• Subject / System• Use case


Use Case Diagram Example

• Consider:• In a museum, visitors can purchase admission ticket

through a clerk.• Purchasing admission ticket requires a payment system,

which will be connected to a bank.• Note that purchasing admission ticket is a kind of help. • In the museum, there is a manager who will mange the

daily activities of the museum


Use Case Diagram Example (cont'd)


System

Actor

Visitor

Clerk

Bank

BuyAdmissionTicket

Payment

SeekHelp

Association/relationship

ManageMuseum

<<include>>

<<extend>>

MuseumManager

answer

Askquestion


• Another example:• In a museum, visitors can purchase admission ticket

through a clerk.• Purchasing admission ticket requires a payment system,

which will be connected to a bank.• Note that the visitors can seek help when purchasing

admission ticket. • In the museum, there is a manager who will mange the

daily activities of the museum




Visitor

Clerk

Bank

BuyAdmissionTicket

Payment

SeekHelp

Notethekeywordherealso

ManageMuseum

<<include>>

<<include>>

MuseumManager

$$$

answer

Activity Diagram

• Graphical representations of workflows of stepwise activities and actions with support for choice, iteration and concurrency. • Constructed from a limited number of shapes,

connected with arrows. Common shapes:• Rounded rectangles represent activities;• Diamonds represent decisions;• Bars represent the start (split) or end ( join) of concurrent

activities;• A black circle represents the start (initial state) of the

workflow;• An encircled black circle represents the end (final state).


Activity Diagram Example

• Online shopping


Searchitem

Viewitem

found

Notfound

Addtocart

like

dislike

Continueshopping

Checkout

Doneshopping

Activity Diagram Example (cont'd)

• Process Order


ReceiveOrder

PaymentProblem

Sendinvoice

Shiporder

CloseOrder

PaymentOK

State Machine Diagram

• Describes the states and state transitions of the system• Many software systems are event-driven• They continuously wait for the occurrence of some external

or internal event such as a mouse click, a button press...• The response to an event generally depends on the

type of the event and the state of the system• E.g. if the user want to add an item to the shopping cart,

but the shopping cart module is not available (i.e., the stateof shopping cart module is down), then the user cannot perform the “add item” action.


State Machine Diagram Example

• For example, in an ATM machine, there are three states, Idle, Active and Out of Service:


StateMachineofATM

Idle

ActiveOutofServices

Putcard

Takecard

Damage

Fixed

Shutdown

Sequence Diagram

• Sequence diagram is the most common kind of interaction diagram, which focuses on the message interchange between a number of lifelines. • A sequence diagram shows, as parallel vertical lines

(lifelines), different processes or objects that live simultaneously, and, as horizontal arrows, the messages exchanged between them, in the order in which they occur. This allows the specification of simple runtime scenarios in a graphical manner.


Sequence Diagram Example

• A simple online bank about transfer money


sd onlinebank

:bank:customer

TransferMoney

Response

Logout

RedirecttoHomepage

Sequence Diagram Example (cont'd)

• Note that a customer should be able to have multiple transfers!


sd onlinebank

:bank:customer

TransferMoney

Response

Logout

RedirecttoHomepage

loop


• We also want to add an option to our customers, such that they can input note before making a transfer!


TransferMoney

Response

Inputreferencenumber

loop

opt


• How about if the customer do not have enough money? We should not make the transfer!


loop

opt Refer tothepreviousslide

TransferMoney

TransferOK

[enoughmoney]

[notenoughmoney]

Transferfail

alt

Sequence Diagram of Facebook


Communication Diagram

• Represents a combination of information taken from Class, Sequence, and Use Case Diagrams, describing both the static structure and dynamic behavior of a system.• Communication diagrams show a lot of the same information as

sequence diagrams, but are clearer to show the interaction among elements, whereas sequence diagrams are clearer to show the order in which the interactions take place.

• Uses free-form arrangement of objects and links. To maintain the ordering of messages, messages are labeled with a chronological number and placed near the link the message is sent. • Reading a communication diagram involves starting at message

1.0, and following the messages from object to object.


Communication Diagram Example


:courseDetail :course

2:getCourseName(courseID):string3:getLocation():json4:getStudentList():array

:student

4.1:getStudentName(studentID):string4.2:getStudentMajor(studentID):string

:location

3.1:getBuildingName(locationID):string3.2:getLocationName(locationID):string

:staff

1.1:inputcourseID1.2:clickenquiry1.3:enquiry(courseID):object

Timing Diagram

• Used to show interactions when the primary purpose of the diagram is to reason about time. • Timing diagrams focus on conditions changing within

and among lifelines along a linear time axis


WebUserIdleWaitingViewing

BrowserIdleProcessingWaiting

ServerIdleProcessing 100ms

10ms20ms

Interaction Overview Diagram

• The interaction overview diagram is similar to combining activity diagrams, sequence diagrams and timing diagrams


Interaction Overview Diagram Example


References

• http://www.uml-diagrams.org/• http://www.uml.org/• https://creately.com/blog/diagrams/uml-diagram-

types-examples/• http://www.visual-paradigm.com/


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