CS计算机代考程序代写 database file system Java c++ Some Clarifications on the Project

Some Clarifications on the Project
• Doesafeature==astory?
– Itdepends…(onthecomplexityofthefeature)
– E.g.”AsauserIwanttobeabletoloadanimagesoIcanview it.” may be one story, or may need to be broken into multiple…
 “As a user I want to be able to load an image from the local file system so I can view my local files.”
”As a user I want to be able to load an image from my OneDrive account so I can view my shared files.”
• Do you have to split all stories into tasks at this stage? (Sprint 0)
– No!Theproductbacklogsimplycontainsstoriesandapriority for each story
CIS 3760
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How Many Stories?
• Product/SprintBacklog
– Itreallydependsonthesizeofthestoriesyoumake,but historically in this class, for the same project, groups typically complete 3-4 user stories per sprint (for 2 week sprint)
 Each story broken down into 4+ tasks (e.g. 1-2 UI changes, 1-2 data/database changes, testing)
– Soacrosstheproject,teamsoftenimplement10+storiesfrom their product backlog. Note, it may not begin this large, but you’ll get better at breaking down stories as per prior slide as you go.
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CIS 3760: Software Engineering OO Design Basics and Unified
Modeling Language (UML)
Instructor: Prof. Stacey Scott
School of Computer Science
University of Guelph https://www.uoguelph.ca/computing/people/stacey-scott stacey.scott@uoguelph.ca
© 2017-20 Stacey D. Scott

Overview
• Review of OO design concepts, modeling, and UML notation
• Review of common UML diagrams:
– Usecasediagrams,Classdiagrams,Sequencediagrams,State Machine Diagrams
• Detailed notes in slide deck for your at-home review
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Software Engineering
SlidesadaptedfromBruegge&Dutoit,Pearsononlineresources 4

Object-Oriented Design Basics: Classes, Objects
UML Class diagram of Class: Cat
CIS 3760
Software Engineering from Shvets, “Dive into Design Patterns”
5

Object-Oriented Design Basics: Inheritance
UML Class diagram with 3 Classes: Animal, Cat, Dog
CIS 3760
Software Engineering
from Shvets, “Dive into Design Patterns”
6

4 Main Pillars of OOP
CIS 3760
Software Engineering from Shvets, “Dive into Design Patterns”
7

Polymorphism example in pseudocode
1 bag = [new Cat(), new Dog()]; 2
3 foreach (Animal a : bag)
4 a.makeSound()
5
6 // Meow!
7 // Woof!
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We use models (e.g. UML) to abstract and describe the software system
• Functionalmodel:Whatarethefunctionsofthe system?
• Object model: What is the structure of the system? • Dynamicmodel:Howdoesthesystemreactto
external events?
• SystemModel:Objectmodel+functionalmodel+ dynamic model
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 9

Transformations b/w Model and Code Space
Model space
Source code space
Model
trans- formation
Reverse engineering
System Model (in UML)
Another System Model
Another Program
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources10
Forward engineering
Program (in Java)
Refactoring

Next-Week’s Deliverable:
Analysis and Modeling of the Existing Code
Model space
Source code space
Model
trans- formation
Reverse engineering
System Model (in UML)
Another System Model
Another Program
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 11
Forward engineering
Program (in Java)
Refactoring

Coding Sprints: (Re-)Implementation
Model space
Source code space
Model
trans- formation
Reverse engineering
System Model (in UML)
Another System Model
Another Program
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 12
Forward engineering
Program (in Java)
Refactoring

What is UML?
• UML (Unified Modeling Language)
– Nonproprietary standard for modeling
software systems
– Proposedandmaintainedby
OMG (Object Management Group)
– Convergenceofnotationsusedinearlierobject-orientedmethods (e.g., Object Modeling Technique, Booch modeling, Object-Oriented Software Engineering)
• Current Version: UML 2.5.1 (2017; OMG UML portal http://www.uml.org)
• Commercial tools: Enterprise Architect (Sparx Systems), Rational Software Architect (IBM), Visual Studio/Visio (Microsoft), SmartDraw, Astah (Change Vision), …
• Open Source tools: PlantUML, ArgoUML, StarUML, Umbrello, …
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 13

If UML is new to you, or you don’t remember it well… recommended web resources for independent review
• https://www.uml-diagrams.org
– Examples of many different UML diagrams
– Our Class Diagrams are typically “conceptual” class diagrams, and relate best to their “Domain Model Diagrams”
• Lynda.com (LinkedIn Learning):
– E.g. Understanding UML: https://www.linkedin.com/learning/c-plus- plus-design-patterns-creational/understanding-uml?u=56996833 (course also has short modules on abstract vs. concrete classes and inheritance vs. composition, which are important concepts to know for using Software Design Patterns)
– E.g. Modeling with UML: https://www.linkedin.com/learning/ software- design-modeling-with-uml/modeling-languages?u=56996833
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Common UML Diagrams
• Use case diagrams
– Describethefunctionalbehaviorof the system as seen by the user
• Class diagrams
– Describethestaticstructureofthe system: Objects, attributes, associations
• Interaction (Sequence) diagrams
– Describethedynamicbehavior between objects of the system
• State machine diagrams
https://d2slcw3kip6qmk.cloudfront.net/marketing/pages/chart/ what-is-a-use-case-diagram-in-UML/UML_use_case_example- 800×707.PNG
– Describethedynamicbehaviorofan individual object
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 15

Common UML Diagrams
• Use case diagrams
– Describe the functional behavior of the system as seen by the user
• Class diagrams
– Describethestaticstructureofthe system: Objects, attributes, associations
• Interaction (Sequence) diagrams
– Describethedynamicbehavior between objects of the system
• State machine diagrams
https://online.visual-paradigm.com/repository/images/e952006a- 41a9-4866-83dd-8dad5219dc15.png
– Describethedynamicbehaviorofan individual object
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 16

Common UML Diagrams
• Use case diagrams
– Describe the functional behavior of the system as seen by the user
• Class diagrams
– Describethestaticstructureofthe system: Objects, attributes, associations
• Interaction (Sequence) diagrams
– Describethedynamicbehavior between objects of the system
• State machine diagrams
https://cdn.visual-paradigm.com/tutorials/ sequenceanimation_screenshots/01-simple-sequence-diagram.png
– Describethedynamicbehaviorofan individual object
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 17

Common UML Diagrams
• Use case diagrams
– Describe the functional behavior of the system as seen by the user
State machine diagram for a Seminar (or Course)
• Class diagrams
– Describethestaticstructureofthe system: Objects, attributes, associations
• Interaction (Sequence) diagrams
– Describethedynamicbehavior between objects of the system
• State machine diagrams
http://agilemodeling.com/style/stateChartDiagram.htm
– Describethedynamicbehaviorofan individual object
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 18

How these common UML diagrams fit into the broader set of UML diagrams
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 19

Different UML diagrams help model different aspects of the system…
• Functionalmodel:Whatarethefunctionsofthe system?
– UMLusecasediagrams
• Object model: What is the structure of the system?
– UMLclassdiagrams(diagramsaresuccessivelyrefined…) • Dynamicmodel:Howdoesthesystemreactto
external events?
– UMLinteraction(sequence)diagrams – UMLstatemachinediagrams
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 20

For this course…
• We will focus on use case, class, and sequence diagrams only
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21

UML Use Case Diagrams
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 22

Use case diagram review
System/ Subsystem Boundary
System/Subsystem Name
Use case diagrams represent the functionality of the system from user’s point of view
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Slides adapted from Bruegge & Dutoit, Pearson online resources 23
Use Case
Actor

Actor
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Example: Use Case Diagram
Actor

Example II: Use Case Diagram SimpleWatch Use Case Diagram (high-level)
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UML Class Diagrams
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 26

Class diagram review
2
2
1 Time
PushButton
state
1
Battery push() blinkIdx Load
release()
blinkSeconds()
blinkMinutes()
blinkHours()
stopBlinking()
refresh()
LCDDisplay
Now
SimpleWatch 1111
Class diagrams represent the structure of the system
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Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 27

Level of Detail of Class Specification
• The class name is the only mandatory information
• When all attributes / operations are also detailed, this is called a
“fully specified” class
A Fully Specified Class
A Class
TarifSchedule
Zone2price: Table
TarifSchedule
getZones(): Enumeration
getPrice(Zone): Price
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(Even more) Fully Specified Class
TarifSchedule
-Zone2price: Table
+getZones(): Enumeration
+getPrice(Zone): Price

Aside: Terminology
• UML: Attribute & Operation • C++: Variable & Function • Java: Member & Method
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Which sentences are true?
a) CheckingAccount implements BankAccount
b) CheckingAccount and SavingAccount are BankAccount c) CheckingAccount and SavingAccount are associated
d) BankAccount is associated with CheckingAccount
e) SavingAccount can processCheck
f) CheckingAccount has a balance
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Some Review & Discussion: Class Diagrams
Questions:
1
2
3
• What type of notation is “1”? What does “0…1” mean?
• What does the number at “2” mean?
• What assumptions did the system designer make? What
other options are there?
• What does the arrow on the association line mean?
• What type of association does “3” indicate?
CIS 3760 •
Software Engineering
What is another design option for this Person-Student,
Person-Professor relationship?
31

Class Diagrams: Right or Wrong?
A B
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Ex I: “Conceptual” Class Diagram for an Order System
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From Fowler & Scott (1997). “UML Distilled”. Addison-Wesley. 33

Ex. II: Same System Modeled as an “Implementation” Class Diagram
Notice the association between Order and Customer now specifies the “navigability” between classes.
Means that Order “knows” about Customer, but Customer does not “know” about Order. In the implementation, this means that Order contains a Customer object, but Customer doesn’t contain an Order object.
Navigability is an implementation detail and is not needed in conceptual Class Diagrams (our main focus in this course)
CIS 3760
Software Engineering
From Fowler & Scott (1997). “UML Distilled”. Addison-Wes3le4y.

Conceptual UML Class Diagram Implementation UML Class Diagram
CIS 3760
Software Engineering
From Fowler & Scott (1997). “UML Distilled”. Addison-Wes3le5y.

Packages
• Packages help you to organize UML models to increase their readability
• We can use the UML package mechanism to organize classes into subsystems
Bank
Customer
• Any complex system can be decomposed into subsystems, where each subsystem is modeled as a package.
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 36
Account

Breakout Room UML Class Interpretation Activity
• See Handout “6-UML Class Diagrams Activity-handout”
• As a group answer the 3 class diagram questions (pp. 5- 7)
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UML Sequence Diagrams
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 38

UML Sequence diagram review – setting the time on the SimpleWatch
:WatchUser
pressButton1()
blinkHours()
Lifeline Activation
pressButton1()
pressButton2()
blinkMinutes()
incrementMinutes()
:SimpleWatch
:LCDDisplay
:Time
pressButton1and2()
commitNewTime()
Message
stopBlinking()
Sequence diagrams represent the behavior of a system
as messages (“interactions”) between different objects
CIS 3760
Slides adapted from Bruegge & Dutoit, Pearson online resources 39
Software Engineering
refresh()
Object

Sequence Diagrams
Focus on Control flow
Passenger
Participating Object
TicketMachine
selectZone()
Message = Operation on
insertCoins()
pickupChange()
zone2price
selectZone()
insertCoins()
pickupChange()
pickUpTicket()
pickUpTicket()
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 40
TicketMachine

Alternatives in control flow
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Software Engineering
https://cdn.visual-paradigm.com/tutorials/ sequenceanimation_screenshots/01-simple-sequence-diagram.png
41

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•
Based only on information you can derive from the Course Registration Sequence Diagram (handout/prior slide), draw a partial UML Class Diagram for the StudentPortal system.
Activity: Understanding Sequence Diagrams
– Include ONLY the CourseSection and Student classes (do NOT include the StudentPortalUI, Course, or Registration classes).
– Fully specify any attributes and operations belonging to each class that would be needed to support the logic and functionality detailed in the Sequence Diagram.
– Detail all associations and their multiplicity between participating classes (based on the diagram AND your domain knowledge of students, courses, and course sections)
• For Zoom:
https://docs.google.com/presentation/d/1H6GYbAnLrzzgeq52
tpDXBJge3FUWF2bfq7ob01SLJ34/copy
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Heuristics for Sequence Diagrams (e.g. good
system design dynamics)
• Layout:
– 1st column: Should be the actor of the use case
– 2nd column: Should be a boundary object
– 3rd column: Should be the control object that manages the
rest of the use case
• Creation of objects:
– Create control objects at beginning of event flow – The control objects create the boundary objects
• Access of objects:
– Entity objects are objects that contain system data
– Entity objects can be accessed by control and boundary
objects
– Entity objects should not access boundary or control object
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Sequence Diagram for the ReportEmergency Use Case
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Better: Sequence Diagram for the ReportEmergency Use Case
Boundary Control Actor Object Object
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Better: Sequence Diagram for the ReportEmergency Use Case
Actor
Boundary Object
Control Object
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Entity Objects?
…

Sequence Diagram for the ReportEmergency Use Case (cont’d)
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UML Basic Notation Summary
• UML provides a wide variety of notations for modeling many aspects of software systems
• We’ve concentrated on a few notations:
– Functional model: Use case diagram
– Objectmodel:Classdiagram
– Dynamicmodel:interaction(sequence)diagram
 Another Dynamic model: state machine diagrams
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 49

UML Modeling Exercise – Translating Problem Domain Description to a Conceptual Design Model
How should we even approach this problem?
What concrete strategies could we use?
Conducting a textual analysis of the problem domain to identify modeling components:
• Identify “entity” objects – the persistent information tracked by the system (Application domain objects, also called “Business objects”)
– Later refinement of the model, or later in the design/development process you will identify “boundary” and “control” objects (previously discussed)
• To identify objects from a problem description, use case description, scenario, etc., you can use the Abbot Technique:
– Textual analysis (noun-verb analysis)
 Nouns are candidates for objects/classes  Verbs are candidates for operations
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Mapping grammatical constructs to model components (Abbot’s Technique)
Example
Grammatical construct
UML model component
“Monopoly”
Proper noun
object
Toy
Improper noun
class
Buy, recommend
Doing verb
operation
Is a
being verb
inheritance
has an
having verb
aggregation
must be
modal verb
constraint
dangerous
adjective
attribute
enter
transitive verb
operation
depends on
intransitive verb
Constraint, class, association
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UML Modeling Exercise – Translating Problem Domain Description to a Conceptual Design Model
Exercise instructions
• Identify the “entity” objects (Classes) (circle in text)
• Identify the associations (draw a box around) – Association
– Aggregations – Inheritance
• Identify the associations / attributes (underline in text)
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A hockey league is made up of at least four hockey teams. Each hockey team is composed of six to twelve players, and one player captains the team. Each player only plays for one team. A team has a name and a record. Players have a number and a position. Hockey teams play games against each other. Each game has a score and a location. Teams are sometimes led by a coach. A coach has a level of accreditation and a number of years of experience, and can coach multiple teams. Coaches and players are people, and people have names and addresses.
53

CIS 3760
Software Engineering
© S. Easterbrook, CSC340, University of Toronto
54

Midterm Information and Prep
• Midterm held during regular Lecture time on Thurs, Mar 4
• Midterm will be given in CourseLink Quiz – Norespondus
• Format:
– Closedquestions(MC,TF,matching,etc.) – Writtenanswers
• More materials and prep next week
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Additional References
• Martin Fowler
– UMLDistilled:ABriefGuidetotheStandardObjectModeling Language, 3rd ed., Addison-Wesley, 2003
• Grady Booch,James Rumbaugh,Ivar Jacobson
– TheUnifiedModelingLanguageUserGuide,AddisonWesley,2nd edition, 2005
• Open Source UML tools
– http://java-source.net/open-source/uml-modeling
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 56

Review Materials to Brush up on if you don’t remember UML (or if you haven’t taken it before)

Abstraction
• Abstraction allows us to ignore non-essential details • Two definitions for abstraction:
• Abstraction is a thought process where ideas are distanced from objects
• Abstraction as activity
• Abstraction is the resulting idea of a thought process where an
idea has been distanced from an object
• Abstraction as entity
• Ideas can be expressed by models
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 58

Brief overview of UML Diagramming Concepts
• Excerpt from Lynda.com tutorial:
• C++ Design Patterns: Creational Patterns
– (UnderstandingUMLsegment)
– https://www.linkedin.com/learning/c-plus-plus-design-patterns- creational/understanding-uml?u=56996833
– This online course also has short modules on abstract vs. concrete classes and inheritance vs. composition, which are important concepts to know for using Software Design Patterns
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More online resources on UML High-level overview by SmartDraw
• SmartDraw System:
– https://www.smartdraw.com/uml-diagram
• Video overview of UML diagramming in SmartDraw: https://youtu.be/tqoS1hPQmXQ)
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UML Core Conventions
•
All UML Diagrams denote graphs of nodes and edges – Nodesareentitiesanddrawnasrectanglesorovals – Rectanglesdenoteclassesorinstances
– Ovalsdenotefunctions
•
Names of Classes are not underlined • SimpleWatch
• Firefighter
•
Names of Instances are underlined • myWatch:SimpleWatch
• Joe:Firefighter
•
An edge between two nodes denotes a relationship between the corresponding entities
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 61

Use Case Diagrams
62

Use Case
PurchaseTicket
• Use cases can be described textually, with a focus on the event flow between actor and system
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Slides adapted from Bruegge & Dutoit, Pearson online resources 63
• A use case represents some functionality provided by the system

Use case diagram basics
Class (not an instance)
Classifier
Use case Function
Actor
Use case diagrams represent the functionality of the system from user’s point of view
CIS 3760
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Slides adapted from Bruegge & Dutoit, Pearson online resources 64
System boundary

UML Use Case Diagrams
Passenger
• Used during requirements elicitation and analysis to represent external behavior (“visible from the outside of the system”)
PurchaseTicket
• The set of all use cases that completely describes the functionality of the system
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Slides adapted from Bruegge & Dutoit, Pearson online resources 65
• Actors & use cases
• Use case model

Actors
Passenger
• An actor has a unique name and an
Name
– Passenger: A person in the train
– GPS satellite: An external system that provides
CIS 3760
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Slides adapted from Bruegge & Dutoit, Pearson online resources 66
• An actor models an external entity which interacts (communicates) with the system:
– User
– External system (Another system)
– Physicalenvironment(e.g.Weather)
optional description • Examples:
Optional Description
the system with GPS coordinates.

Use Cases often have an Accompanying Textual Description, e.g.
1. Name: Purchase ticket 2. Participating actor:
5. Flow of events:
Passenger
1. Passenger selects the number of zones to be traveled
3. Entry condition:
2. Ticket Distributor displays the amount due
• Passenger stands in front of ticket distributor
3. Passenger inserts money, at least the amount due
• Passenger has sufficient money to purchase ticket
4. Ticket Distributor returns change
4. Exit condition:
• Passenger has ticket
5. Ticket Distributor issues ticket 6. Special requirements: None.
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 67

Passenger
• It has been 15 hours, but the passenger has not finished the purchase process …
PurchaseTicket
• Purchasing a single ticket and purchasing a multi-trip pass involves the same type of money collection process. Do we need to write two different use cases?
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Slides adapted from Bruegge & Dutoit, Pearson online resources 68
But …
• What if the passenger cancels the ticket purchase before completing the purchase?

Uses Cases can be related
• Extends Relationship
– To represent seldom invoked use cases or exceptional functionality
• Includes Relationship
– Torepresentfunctionalbehaviorcommontomorethanoneuse case.
CIS 3760
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Slides adapted from Bruegge & Dutoit, Pearson online resources 69

The <> Relationship
<>
OutOfOrder
<>
Passenger
• The exceptional event flows are factored out of the main event flow for clarity
PurchaseTicket
• The direction of an <> relationship is to the extended use case
<>
Cancel
CIS 3760
Software Engineering
NoChange
• models exceptional or seldom invoked cases
<>
TimeOut
Slides adapted from Bruegge & Dutoit, Pearson online resources 70

The <> Relationship
Passenger
• <> behavior is factored out for reuse, not because it is an exception
PurchaseMultiCard
PurchaseSingleTicket
• The direction of a <> relationship is to the using use case (unlike the direction of the <> relationship)
<>
<>
<>
CollectMoney
NoChange
Cancel
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Slides adapted from Bruegge & Dutoit, Pearson online resources 71
<>
• Represents common functionality needed in more than one use case

The <> Relationship
• Specializes the parent use case
PayWithCash
PayWithCreditCard
CollectMoney
• The parent use case represents the general steps
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Slides adapted from Bruegge & Dutoit, Pearson online resources 72
by adding more details
• The child use case inserts additional steps or refines steps

Class Diagrams
73

Class diagram basics
Multiplicity
https://cdn.instructables.com/F26/MSCX/ J8F5SWIB/F26MSCXJ8F5SWIB.LARGE.jpg
􏱓
􏱔􏱔􏱔􏱔 􏱔
􏱓􏱔
3XVK%XWWRQ
‘LVSOD\ %DWWHU\ 7LPH
Association
6LPSOH:DWFK
Class diagrams represent the structure of the system
CIS 3760
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Slides adapted from Bruegge & Dutoit, Pearson online resources 74
Class

Class diagram basics (cont’d)
Class diagrams represent the structure of the system
Association Multiplicity
Class
2
2
1 Time
PushButton
state
1
Battery push() blinkIdx Load
release()
blinkSeconds()
blinkMinutes()
blinkHours()
stopBlinking()
refresh()
Attribute
Operations
Slides adapted from Bruegge & Dutoit, Pearson online resources 75
CIS 3760
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LCDDisplay
SimpleWatch 1111
Now

Class Diagrams
• Used during requirements analysis to model application domain concepts
• Used during design activities to model subsystems and to specify the detailed behavior and attributes of classes
• Can be modeled at different levels of detail, depending on purpose
TarifSchedule
Trip
zone:Zone
Table zone2price
Enumeration getZones()
Price getPrice(Zone)
*
*
Price: Price
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 76

• •
A class represents a concept
A class encapsulates state (attributes) and behavior (operations)
Classes
Type
TarifSchedule
zone2price
getZones()
getPrice()
Signature
Name Attributes
Zone2price: Table
getZones(): Enumeration
getPrice(Zone): Price
Operations
Each attribute has a type
Each operation has a signature (operation name, arguments, and return type)
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources
TarifSchedule

Associations
TarifSchedule
TripLeg
getZones(): Enumeration
getPrice(Zone): Price
*
*
Price Zone
Associations denote relationships between classes
The multiplicity of an association end denotes how many objects the instance of a class can legitimately reference:
– No multiplicity implies 1
– 0…1 – zero or one
– 0…n–0ton(n>=1) – 0…*or*-0tomany – 1…*-1tomany
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources
Multiplicity

Aggregation Association
• An aggregation is a special case of association denoting a “consists-of” hierarchy
Exhaust system
• The aggregate is the parent class, the components are the child classes
1
0..2
A solid diamond denotes composition: A strong form of aggregation where the life time of the component instances is controlled by the aggregate. That is, one part “owns” the other, not just “uses” (as in aggregration).
CIS 3760
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Slides adapted from Bruegge & Dutoit, Pearson online resources 79
TicketMachine
3
Muffler diameter
Tailpipe diameter
ZoneButton

Inheritance Association
CancelButton
ZoneButton
Button
• Inheritance is another special case of an association denoting a “kind-of” hierarchy
• Inheritance simplifies the analysis model by introducing a taxonomy
• The child classes inherit the attributes and operations of the parent class.
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Slides adapted from Bruegge & Dutoit, Pearson online resources

Defining Visibility in Class Diagrams Specifies who can “see” or access the attribute or
operation in the class (i.e. its scope)
https://miro.medium.com/max/1300/1*cjxQc8YklOZGQNeCQVmGkg.png
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Model-Driven Software Development
1. Build a platform-independent model of an applications functionality and behavior
a) Describe model in modeling notation (UML) b) Convert model into platform-specific model
2. (Automatically) generate executable from platform- specific model
Advantages:
– Code is (“mostly”) generated from model
– Portability and interoperability
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 82

Model-driven Software Development
Reality: A stock exchange lists many companies. Each company is identified by a ticker symbol.
Analysis results in analysis object model (UML Class Diagram):
StockExchange
**
Company tickerSymbol
Implementation results in source code (Java):
are mapped to
Lists
public class StockExchange {
public Vector m_Company = new Vector();
};
public class Company {
};
public int m_tickerSymbol;
public Vector m_StockExchange = new Vector();
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 83
Associations
Attributes!

Sequence Diagrams
84

UML Sequence diagram basics
Actor Message Object Lifeline
:WatchUser
:SimpleWatch :LCDDisplay :Time
pressButton1()
blinkHours()
pressButton1()
pressButton2()
blinkMinutes()
incrementMinutes()
pressButton1and2()
commitNewTime()
Activation
stopBlinking()
Sequence diagrams represent the behavior of a system
as messages (“interactions”) between different objects
CIS 3760
Slides adapted from Bruegge & Dutoit, Pearson online resources 85
Software Engineering
refresh()

Sequence Diagrams
Passenger
– to find additional “participating” objects
TicketMachine
selectZone()
– To refine use case descriptions
insertCoins()
• Instances are represented by rectangles, Actors by stick figures
pickupChange()
• Lifelines are represented by dashed lines
pickUpTicket()
• Activations are represented by narrow rectangles.
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 86
• Used during analysis
• Used during system design
– to refine subsystem interfaces
• Messages are represented by arrows

•
The source of an arrow indicates the activation which sent the message
•
Horizontal dashed arrows indicate data flow, for example return results from a message
Sequence Diagrams can also model Data Flow
Passenger
ZoneButton TarifSchedule Display
selectZone()
lookupPrice(selection)
Dataflow
displayPrice(price)
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 87
price
…continued on next slide…

Sequence Diagrams: Iteration & Condition
Passenger
ChangeProcessor CoinIdentifier
Display
CoinDrop
• •
Iteration is denoted by a * preceding the message name
Condition is denoted by boolean expression in [ ] before the message
*
insertChange(coin)
Iteration Condition
price
displayPrice(owedAmount)
name
…continued from previous slide…
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 88
lookupCoin(coin)
[owedAmount<0] returnChange(-owedAmount) ...continued on next slide... Creation and destruction Passenger ChangeProcessor Creation of Ticket <>
…continued from previous slide…
<>
print()
<>
Destruction of Ticket
Ticket
• Creation is denoted by a message arrow to the object and the label
• Destruction is denoted by an X mark at the end of the destruction activation, typically also by the label <>
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 89

Sequence Diagram Properties
• UML sequence diagram represent behavior in terms of interactions
• Useful to identify missing objects
• Time consuming to build, but worth the investment
• Complement the class diagrams (which represent structure).
CIS 3760
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources 90

How do we detect Operations?
• We look for objects that are interacting and extract their “protocol”
• We look for objects that have interesting behavior on their own
• Good starting point: Flow of events in a use case description
• From the flow of events we proceed to the sequence diagram to find the participating objects.
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What is an Event?
• Something that happens at a point in time
• An event sends information from one object to another
• Events can have associations with each other: – Causallyrelated:
 An event happens always before another event
 An event happens always after another event – Causallyunrelated:
 Events that happen concurrently
• Events can also be grouped in event classes with a
hierarchical structure => Event taxonomy.
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Software Engineering
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The term ‘Event’ is often used in two ways
• Instance of an event class:
– “Slide14shownonFridayNovember27at9:23”
– Event class “Lecture Given”, Subclass “Slide Shown”
• Attribute of an event class
– SlideUpdate(8:55AM,11/27/2009)
– Train_Leaves(4:45pm, Manhattan)
– Mousebuttondown(button#,tablet-location).
CIS 3760
Software Engineering
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Finding Participating Objects for Sequence Diagram
• Heuristic for finding participating objects:
– Aeventalwayshasasenderandareceiver
– Findthesenderandreceiverforeachevent=>Thesearethe objects participating in the use case.
CIS 3760
Software Engineering
94

An Example
• Flow of events in “Get SeatPosition” use case :
1. Establish connection between smart card and onboard computer
2. Establish connection between onboard computer and sensor for seat
3. Get current seat position and store on smart card • Where are the objects?
CIS 3760
Software Engineering
95

time
Sequence Diagram for “Get SeatPosition”
1. Establish connection between smart card and onboard computer
Establish Connection
2. Establish connection between onboard computer and seat (actually seat sensor)
Accept Connection
3. Get current seat position and store
Accept Connection Get SeatPosition
on smart card.
“500,575,300”
Smart Card Onboard Computer Seat Establish Connection
CIS 3760
Software Engineering
96

What else can we get out of Sequence Diagrams?
• Sequence diagrams are derived from use cases
• The structure of the sequence diagram helps us to determine how decentralized the system is
• We distinguish two structures for sequence diagrams – Fork Diagrams and Stair Diagrams (Ivar Jacobsen)
CIS 3760
Software Engineering
97

Fork Diagram
• The dynamic behavior is placed in a single object, usually a control object
Control Object
– Itknowsalltheotherobjectsandoftenusesthemfordirect questions and commands
CIS 3760
Software Engineering
98

Stair Diagram
• The dynamic behavior is distributed. Each object delegates responsibility to other objects
– Eachobjectknowsonlyafewoftheotherobjectsandknows which objects can help with a specific behavior
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Software Engineering
99

Fork or Stair?
• Object-oriented supporters claim that the stair structure is better
• Modeling Advice:
– Choose the fork (a centralized control structure) if
 The operations can, and may, change order
 New operations are expected to be added as a result of new requirements.
– Choosethestair(adecentralizedcontrolstructure)if
 The operations have a strong connection
 The operations will always be performed in the same order
 Care must be taken with this model in a thread-based
system if multiple objects may change the state of the
same data object
CIS 3760
Software Engineering
100

Additional Materials (optional)
101

Basics of State Machine Diagram
CIS 3760
Software Engineering
102
Slides adapted from Bruegge & Dutoit, Pearson online resources

State Machine Diagram (basics)
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behavior.
103
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources
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State
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Event
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dynamicCIS 3760
behavior.
104
Software Engineering
Slides adapted from Bruegge & Dutoit, Pearson online resources
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