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CONCEPTUAL DESIGN: OBJECT TECHNOLOGY CONCEPTS and UML CLASS DIAGRAMS. A Simplified Object-Oriented Systems Analysis & Conceptual Design Methodology. Activities. Identify the information system’s purpose Identify the information system’s actors and features
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CONCEPTUAL DESIGN: OBJECT TECHNOLOGY CONCEPTS andUML CLASS DIAGRAMS
A Simplified Object-Oriented Systems Analysis & Conceptual Design Methodology Activities • Identify the information system’s purpose • Identify the information system’s actors and features • Identify Use Cases and create a Use Case Diagram • Identify Objects and their Classes and create a Class Diagram • Create Interaction/Scenario Diagrams • Create Detail Logic for Operations • Repeat activities 1-6 as required to refine the “blueprints”
Object-Oriented Technology Concepts • Object • Class • Attributes • Operations • Relationships • Messages • Persistence • State
Defining Objects An OBJECT is an abstraction of a person, place, thing, or concept within the problem domain that the information system must be aware of. ...Objects are “instantiated” (created) ...the term “instance” is interchangeable with “object”
Defining Class A CLASS is a template (specification, blueprint) for a collection of objects that share a common set of attributes and operations. HealthClubMember attributes operations Class Objects
Objects • Objects have three responsibilities: • What they know about themselves – (e.g., Attributes) • What they do – (e.g., Operations) • What they know about other objects – (e.g., Relationships)
Attributes (aka: properties, characteristics) An ATTRIBUTE is data that further describes an object instance. firstName lastName Mary Smith Susan Jones Jeff Norman etc... HealthClubMember • attributes • firstName • lastName • etc... • operations Class Objects
StudentInformation An example of a Class showing Attribute Names and their Values Class “template” 8 Object Examples With Attribute Values studentName address shoeSize eyeColor weight dateOfBirth etc... operations studentName address shoeSize eyeColor weight dateOfBirth 4-12-74 12-2-73 10-5-76 6-28-75 3-15-74 5-22-75 1-26-70 8-14-74 Susan McIntyre Greg Fisher Minder Chen Sally Athey Laura Applegate Margie Heltne Bill Martz Anna Easton 123 Franklin St. San Diego CA 765 Park Ave. San Diego CA 222 Dallas St. La Mesa CA 862 Grand Ave. Pacific Beach CA 914 Garnett La Jolla CA 479 55th St. El Cajon CA 876 Balboa Mission Beach CA 309 Del Mar Hts. Del Mar CA 11 10 9.5 6 5 5.5 10.5 6 Blue Brown Brown Brown Blue Brown Blue Brown 175 170 140 125 110 105 190 120
StudentInformation What are the necessary attributes? attributes operations Necessary Attributes Candidate Attributes studentSocialSecurityNumber studentFirstName studentMiddleInitial studentLastName studentAddress studentCity studentState studentZipcode studentTelephone yearGradFromHighSchool highSchoolGradePointAvg sATScore hobbies sports religiousPreference medicalCondition height weight shoeSize hairColor eyeColor gender etc... studentSocialSecurityNumber studentFirstName studentMiddleInitial studentLastName studentAddress studentCity studentState studentZipcode studentTelephone yearGradFromHighSchool highSchoolGradePointAvg sATScore religiousPreference medicalCondition gender etc... ANALYSIS
Single-Valued Attributes Example studentName studentIDNumber eyeColor height weight dateOfBirth Susan McIntyre Bill Martz 559-46-0912 371-38-7640 Blue Brown 5ft 9in 5ft 6in 155 118 4-12-74 12-2-73 (each object has one and only one value for each attribute at any moment in time) Mutually Exclusive Attribute Values Example employeeName employeeNumber hourlyRate weeklySalary 559-46-0912 371-38-7640 $9.75 Susan McIntyre Bill Martz $475.00 mutually exclusive attributes with values (the presence of an object’s attribute value necessitates the absence of a value for another attribute value for the same object)
Multi-Valued Attributes Example studentName studentIDNumber collegeAttended collegeGradePointAvg 559-46-0912 371-38-7640 270-73-9815 Grossmont C.C. Point Loma NY Univ. Golden Gate Georgia State U of San Diego 2.9 2.7 3.2 2.2 2.9 3.1 Susan McIntyre Bill Martz Maria Carey multi-valued attributes with values studentName studentIDNumber collegeAttended collegeGradePointAvg 2.9 2.7 3.2 2.2 2.9 3.1 Susan McIntyre Susan McIntyre Bill Martz Maria Carey Maria Carey Maria Carey Grossmont C.C. Point Loma NY Univ. Golden Gate Georgia State U of San Diego 559-46-0912 559-46-0912 371-38-7640 270-73-9815 270-73-9815 270-73-9815 Notice the redundancy of data values for these two attributes
(revised model) (original model) StudentInformation CollegeAttended StudentInformation studentName studentIDNumber collegeAttended collegeGradePointAvg studentName studentIDNumber collegeAttended collegeGradePointAvg 0,m 1 operations operations operations studentName studentIDNumber 559-46-0912 371-38-7640 270-73-9815 Susan McIntyre Bill Martz Maria Carey collegeAttended gradePointAvg Grossmont C.C. Point Loma NY Univ. Golden Gate Georgia State U of San Diego 2.9 2.7 3.2 2.2 2.9 3.1
Operations (aka: methods, services, behavior) An OPERATION is a procedure that an object can perform. HealthClubMember An object’s “motto”: • attributes • firstName • lastName • etc... • operations • joinClub • payFees • monitorWorkout • etc... “I do it myself” Class Objects
Relationships A RELATIONSHIP is what a class or an object knows about another class or object. • Generalization[-Specialization](Superclass/Subclass) • Inheritance • Ex: Person - FacultyPerson, StudentPerson, Staff... • Ex: ModesOfTravel - Airplane, Train, Auto, Cycle, Boat... • [Object] Associations • FacultyInformation - CourseInformation • StudentInformation - CourseInformation • [Object]Aggregations & Composition(Whole-Part) • Assembly - Parts • Group - Members • Container - Contents T h r e e T y p e s
Relationships Exist to: 1) show relationships 2) enforce integrity 3) help produce results In this example: • Removal of a course should also remove students that are in the course but not student information. • Removal of a student should also remove students that are in courses but not course information. • Removal of a student in a course should not affect either course or student information. UniversityCourse 1 StudentInformation 0,m 1 StudentInCourse 0,m
Messages A MESSAGE is a signal from one object to another that requests the receiving object to carry out one of its operations. Three parts to a Message: 1. The name of the receiver object 2. The operation to carry out 3. Any parameters the operation may require to fulfill its duties “The operation is the message.” Message: getFrozenYogurt operation: getFrozenYogurt($$)
VCR Example T.V. Object VCR Object Play Message Universal Remote Control VCR Class Definition
Persistence PERSISTENCE is the equivalent of more permanent, long-term data storage. • State STATE represents the condition of an object at a specific moment in time. Time Account Balance 6:00pm $2,500 6:05pm $2,200 (something changed its state)
Getting Started! Getting Started! Getting Started! Getting Started! Getting Started! Getting Started!
GETTING STARTED with the CLASS DIAGRAM • Features? • Data? • User Behavior? OBJECTS! (CLASSES)
{ Member memberNumber firstName lastName telephone address city etc... Expanded view of a Class into its three sections: Top: Class Name Middle: attributes Bottom: operations attributes { checkOutVideo checkInVideo buyItem etc... operations UML Class Diagram Notation Class
Class Class . . . card #52 . . card #4 card #3 card #2 card #1 Playing Card Illustration of Class Symbol Deck of 52 Playing Cards Object #n Object #3 Object #2 Object #1
STRATEGIES for FINDING OBJECTS (Classes) • Wirfs-Brock Noun Phrase • Conglomeration of others: • Look for tangible things • Consider roles played • Identify incidents/interactions which are often transaction-like • Find any specifications (table-like) • Other…
Wirfs-Brock Noun Phrase (also Wilkerson, Wiener) • Circle or underline nouns and noun phrases that occur in the requirements document(s); these become candidate classes (objects) • Put candidate classes on a separate list • Challenge each one; look for synonyms Examples: The system will keep track of membership information The system will manage inventory The system will facilitate the selling of bicycles
INFORMATION SYSTEMS OBJECTIVES GENERAL OBJECTIVES: A. Provide Just-in-Time (JIT) training B. The systems we implement must be friendly and easy to learn and use C. The systems we implement must give considerations to security issues SPECIFIC OBJECTIVES: 1.1.1 Provide an automated system to assist with customer sales/rental check-outs 2.1.1 Provide and maintain an automated membership database a. provide current (up to date) membership information on demand b. capability to add, change, and delete (remove) membership info. 2.1.2 Provide membership information reports such as (not limited to): a. least used memberships b. most used memberships c. delinquent memberships (both money owing and outstanding rentals) 4.1.1 Provide and maintain an inventory database for both sales and rental items a. provide current (up to date) inventory information on demand b. capability to add, change, and delete (remove) inventory information (sales and rental) 4.1.2 Provide inventory information reports such as (not limited to): a. least popular rentals b. most popular rentals c. delinquent tape rentals outstanding d. products “on order” (purchasing report) for sale and for rent items 5.1.1 Provide Sales Reports such as (not limited to): a. sales for a time period (day, days, week, weeks, month, etc.) by product code b. rentals for a time period (same as above) F i n d i n g O b j e c t s
WIRFS-BROCK NOUN PHRASE STRATEGY Security Issue Automated System Customer Sales/Rental Check-out Membership Database Membership Information Membership Information Report Inventory Database Sales And Rental Item Inventory Information Inventory Information Report Sales Report Candidate List of Classes
Other Strategies To Find Objects • Look for tangible things • people, places, things • Consider roles played • student, faculty, clerk, manager, salesperson, race car driver, etc... • Identify incidents/interactions which are often transaction-like • sales, purchases, reservations, etc... • Find any specifications (table-like) • state tables, tax rate tables, zipcode table, shipping region table, etc...
CHALLENGE CLASSES/OBJECTS BASED ON: • Needed remembrance (persistence) • No Attributes • No Operations • Only one Object • Avoid derived (computed) results
BECK & CUNNINGHAM’s CRC STRATEGY (low-fidelity/tech way of documenting classes) (CRC = Class-Responsibility-Collaboration) Class Name Responsibilities (attributes and operations) Collaborations (relationships) 4x6 Card Order orderNumber orderDate check if items in stock determine price check for valid payment dispatch to delivery address etc... Order Line Order Line Customer etc...
Video Store Information System Candidate List of Classes - Pass One • Members • Customers • Movies • Reports • Concessions • Sales • Games • Inventory • VCR Rentals • Movie Rental • Employees • Automated System • Hardware • Software • Back-up System • Bonus Plan • P.O.S. Terminal • Clothing • Transaction • Marketing • Popcorn • Prices • Physical Environment • Scheduling • Location • Accounting • Advertising • Overhead • Database • Payroll
Video Store Information System List of Classes – Final Pass • RentalTransaction • Member • Employee • StoreLocation • Supplier • Purchase Order • Purchase Order Line Item • SaleRentalLineItem • Inventory * • Video • Game • ConcessionItem • VCR • Transaction * • SaleTransaction • SaleItem* • RentalItem* Note: * denotes an Abstract Class (no Objects)
Class Attributes Video Store Classes showing Attributes - Part 1 of 3 Member memberNumber memberName memberAddress memberCity memberState memberZipCode memberPhone creditCardNumber creditCardExpireDate depositAmount Video barCodeNumber description qtyOnOrder price cost taxCode timesRented dueDate memberNumber quantitySold qtyOnHand
Class Attributes Game (same as Video) ConcessionItem barCodeNumber description qtyOnOrder price cost taxCode quantitySold qtyOnHand VCR barCodeNumber description qtyOnOrder price cost taxCode timesRented dueDate memberNumber SalesTransaction transactionNumber employeeNumber transactionDate transactionTime barCodeNumber price salesTax quantitySold Video Store Classes showing Attributes - Part 2 of 3
Class Attributes • RentalTransaction transactionNumber • employeeNumber • transactionDate • transactionTime • barCodeNumber • price • salesTax • memberNumber • Employee employeeNumber • employeeName • employeePhone • positionCode • StoreLocation storeNumber • address • city • state • zipcode • telephone • Vendor vendorNumber • vendorName • vendorAddress • vendorCity • vendorState • vendorZipCode • vendorPhone • vendorFaxNumber • PurchaseOrder purchaseOrderNumber • purchaseOrderDate • purchaseOrderDueDate • purchaseOrderCancelDate • barCodeNumber • quantityOrdered • vendorNumber • itemCost Video Store Classes showing Attributes - Part 3 of 3
Video Store Attribute Data Dictionary (partial) Attribute Class Definition/Rules • barCodeNumber Inventory Up to 12 characters • Transaction Up to 12 characters • creditCardExpireDate Member MM/YY (month, year) • creditCardNumber Member Up to 19 characters • cost Inventory range: 0 to 999.99 • depositAmount Member min: $25; max: $200 • description Inventory 40 characters • employeeNumber Transaction 6 digits • memberAddress Member 30 characters (no P.O. Box) • memberCity Member 30 characters • memberName Member 30 characters • etc.....
Video Store – UML Class Diagram 1 1 Inventory RentalItem SaleItem Video ConcessionItem Game VCR 0..* 0..* StoreLocation Transaction Employee 1 1 SaleTransaction RentalTransaction Suplier 0..* 1 1 0..* 1 1 0..1 0..* Member PurchaseOrder 1 1..* 1..* 1..* SaleRentalLineItem 0..* 0..* PurchaseOrderLineItem
Video Store Future Enhancements List - Final Pass 1. Open-ended memberships (indefinite; ie: no cancellations) with C.C. or $50 deposit (P) 2. Establish Bonus Point System for rentals (ie: rent 9 get one rental free, etc.) (E) 3. Handle special orders for videos (E) 4. Ability to reserve a movie ahead of time (E) 5. Automatic billing to credit card at end of month for month's charges (E) 6. Establish a membership DEBIT card (E) 7. Allow a monthly "tab" to be paid at the end of the month (see #5) (E) 8. No physical security devices on videos (P) 9. System will not include Payroll system, Accts. Payable, or Financial systems such as General Ledger and Income Statements (P) 10. The system will not keep information on non-member customer sales (P) 11. Game inventory can be for sale or rent (but only one of these at a time) (P) 12. The system will NOT include any work shift scheduling of employees (P) 13. The Video Store will rent VCRs 14. Payment for Rental transactions will be at time of transaction (not when item returned) NOTE: (P) = Policy decision (E) = Potential Future Enhancement
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