Ist.psu.edu School of Information Sciences and Technology IST 311 – Object-Oriented Design &...

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School of Information SciencesSchool of Information Sciencesandand TechnologyTechnology

IST 311 – Object-Oriented Design & Software

Steven Haynes

IST 311 – Class 7

17 January 2006

shaynes@ist.psu.edu

Mid-Term Deliverables

Use Case diagrams– Derived from scenarios

• Class diagram– Conceptual

• Sequence diagrams TBD– Need use cases first

• User Interface Design– Need use cases first

• Due Thursday, March 3rd (Thursday before break)

Design Representations

• Why learn the UML?

• What is the purpose of design representation languages and techniques?

Design Representations

• An aid to design cognition

• A common language for communicating about a design (specifications)

• A record of the design process and its outcomes (documentation)

UML Diagrams, Part 1.

• Use Case diagram

UML Diagrams

• Use Case diagram– Identify major services provided by a system to

external actors (users and other systems)• Establish the boundaries of the system

• Identify common functionality

• Identify high-level alternate use scenarios

– Capture requirements– Development project planning tasks– Communicate with the customer/user.

Use Case Diagram

Customer

Purchase Gas

Initialize Pump

«uses»

Card Purchase

«extends»

Bank System

Print Receipt

«extends»

Use Cases

• Actors• Use Cases• Include (Uses) Use Cases• Extend Use Cases• Annotations

– Pre-conditions

– Post-conditions

– Constraints

• Don’t use actor or use case generalization

Guidelines for Use Cases

• Actors – specific user roles• Human actors on left• Non-human actors (systems) on right• Use Cases – verb-noun phrase• e.g., Verify Credit Card• Include (uses) link – included use case MUST be

completed for the including use case to complete• Extend link – extending use case represents a

variant of the extended use case

Guidelines for Use Cases

• Use cases model system interactions.

• Use case granularity THE big problem

• Use annotations (notes) freely to document your assumptions.

• Use cases are not data stores

• Use cases are not data flow diagrams

UML Diagrams

• Class diagram

UML Diagrams

• Class diagram– Identify classes

• Attributes

• Operations

– Identify class relationships– Identify packages– Describe a system’s static structure

Class Diagram

+Pump_Controller_UI()+createTransaction()+monitorCardReader()+sendAttendantMsg(in message : String)+initializePump()+getSelectedFuelProduct()+promptSwipeCard()+startDispenser()+transTypeButton2_actionPerformed()+setCustomerMsg(in msg : String)+setFuelProductLabel()

-startButton-cancelButton-transTypeButton1-transTypeButton2-transTypeButton3-gradeSelectButton1-gradeSelectButton2-gradeSelectButton3-customerMessage : JTextArea-unitsDispensed : JTextField-totalSaleAmount : JTextField-pricePerUnit : JTextField-pumpNumberField : JTextField

Pump_Controller_UI

+createDispenser()+calcTotalSale()+printReceipt()+Transaction()

-totalSaleAmount : double-unitsSold : double-date : String

Transaction

+verifyCard() : boolean+chargeCard()

-cardCompany : String

Credit_Card

+printReceipt()+Card_Transaction()+cardReaderReady() : boolean

Card_Transaction

+verifyCard() : boolean+chargeCard()+Payment_Card()

-cardNumber : String-nameOnCard : String-expirationDate : String-cardVerifiedIndicator : boolean-amountAvailable : double

Payment_Card

+verifyCard() : boolean+chargeCard()

-cardBank : String-pinNumber

Debit_Card

UML Diagrams

• Sequence diagram

UML Diagrams

• Sequence diagram– Describe the sequence of steps required to

realize a use case or use case scenario, which represent requirements

– Describe interactions between objects/classes– Perspective is time oriented

Sequence Diagram

aCustomer

aPump_Controller_UI

Pump_Controller_UI()createTransaction()

aTransaction

Transaction()

UML Diagrams

• Collaboration diagram

UML Diagrams

• Collaboration diagram– Same as Sequence diagram except…– Perspective is structural or spatial

Collaboration Diagram

Customer

: PC::Pump_Controller_UI

1: transTypeB

utton2_actionPerform

: PC::Card_Transaction

: PC::Card_Reader

3: Card_R

eader()

4: card

ReaderReady:=

cardReaderR

eady()

5: setCustom

erMsg(m

sg:String)

: PC::Payment_Card

6: Paym

ent_Card()

Degree Audit Use Cases & Classes

Eclipse Tutorial

Assignment for Thursday

• This is an individual assignment.

• If you have not had Java it will take some time so don’t wait too late to start working.

• Read Raposa Chapters 1 through 3.

• Do problems on the next two slides.• For this assignment you can use the Java SDK for the labs,

as described in the book, or Eclipse.

• Due at the start of class Thursday, 1/19.

Assignment Lab 1

• Write a public class called CreditCalculator and declare the main() method within the class.

• The value for currentCredits will be input from the command line. Command-line arguments are strings so you’ll need to convert the value of currentCredits to an integer within main():int currentCredits = Integer.parseInteger(args[0]);* Hint Run menu:Run, then the Arguments tab

• Write a method to calculate creditsNeeded given the value of currentCredits. Display the result.

• Save, compile, and run your program. You’ll need to enter the command-line argumentjava CreditCalculator 62

Assignment Lab 2

• Extend the main() method in your CreditCalculator class to calculate the number of semesters remaining given 15 credits per semester.

• Also, if the number of currentCredits is >= 120, output the string “You can graduate!”

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