CS616 Software Engineering II

Lecture 9

Larman Part5 Elaboration: Iteration 3

Chapter 24 Iteration 3 and its Requirements

Iteration 3 Requirements

 

Iteration 3 Emphasis

Broad view of design exploring:

 

Chapter 25 Relating Use Cases

1.     The Include Relationship

       Most common and important organizing relationship

       E.g.

 

UC1: Process Sale

Main Success Scenario (or Basic Flow):

1. Customer arrives at POS checkout with goods and/or services to purchase.

7. Customer pays and System handles payment.

 

Extensions

7b. Paying by credit: Include Handle Credit Payment

7c. Paying by check: Include Handle Check Payment

 

UC7: Process Rental

Extensions

6b. Paying by credit: Include Handle Credit Payment

 

UC12: Handle Credit Payment

Level: Subfunction

Main Success Scenario:

  1. Customer enters their credit account information
  2. System sends payment authorization request to an external Payment Authorization Service System, and requests payment approval.
  3. System receives payment approval and signals approval to cashier

 

Extensions:

2a. System detects failure to collaborate with external system:

1. System signals error to Cashier.

2. Cashier asks Customer for alternate payment

 

 

NOTE: Handle Credit Payment subfunction use case was originally in extension section of Process Sale use case., but factored out to avoid duplication.

2.     The extend Relationship

       Create an extending use case

       Within it describe where and under what conditions it extends the behavior of some base use case

UC1: Process Sale (the base use case)

Extension Points: VIP Customer, step 1. Payment, step 7.

Main Success Scenario (or Basic Flow):

1. Customer arrives at POS checkout with goods and/or services to purchase.

7. Customer pays and System handles payment.

 

 

3.     Use Case Diagrams

Figure Use case include relationship

 

Figure extend relationship

 

 

Chapter 26 Modeling Generalization

1.     New Concepts for the Domain Model

1.     Create generalization-specialization hierarchies

 

Concepts Category List

Category

Examples

Physical and tangible objects

Credit Card, check

Specifications, designs, or descriptions of things

 

Places

 

Transactions

CashPayment, CreditPayment, CheckPayment

Transaction line items

 

Role of people

 

Containers of other things

 

Things in a container

 

Other computer or electro-mechanical systems external to system

CreditAuthorizationService, CheckAuthorizationService

Abstract noun concepts

 

organizations

CreditAuthorizationService, CheckAuthorizationService

Events

 

Rules and policies

 

Catalogs

 

Records of finance, work, contracts, legal matters

AccountsReceivable

Financial instruments and services

 

Manuals, books

 

 

Noun Phrase Identification from the Use Cases

Extensions

7b. Paying by credit:

1 Customer enters their credit account information.

2. System sends payment authorization request to an external Payment Authorization Service System, and requests payment approval.

2a. System detects failure to collaborate with external system:

1. System signals error to Cashier.

2. Cashier asks Customer for alternate payment.

3. System receives payment approval and signals approval to Cashier.

3a. System receives payment denial:

1. System signals denial to Cashier.

2. Cashier asks Customer for alternate payment.

4. System records the credit payment, which includes the payment approval.

5 System presents credit payment signature input mechanism.

6. Cashier asks Customer for a credit payment signature. Customer enters signature.

 

2.     Generalization

       Concepts CashPayment, CreditPayment, and CheckPayment all similar

       Organize them into generalization-specialization class hierarchy

 

 

3.     Defining Conceptual SuperClasses and Subclasses

 

 

 

4.     When to define a Conceptual Subclass

       Create a conceptual subclass of a superclass when:

 

5.     When to define a Conceptual SuperClass

o      The potential conceptual subclasses represent variations of a similar concept

o      The subclasses will conform to Is-a rule

o      All subclasses have the same attribute which can be factored out and expressed and expressed in the superclass

o      All subclasses have the same association which can be factored out and related to the superclass

 

6.     NEXGEN POS Conceptual Class Hierarchies

Payment Classes

Figure Justifying Payment subclasses

 

Authorization Services Classes

 

7.     Abstract Conceptual Classes

       Every member of a class C must also be a member of a subclass, then class C is called and abstract conceptual class

       e.g. every Payment instance must be an instance of the subclass CashPayment, CreditPayment, and CheckPayment

       since every Payment member is also a member of a subclass, Payment is an abstract conceptual subclass

Figure abstract conceptual classes