Exercises

Exercises - 19Analysis and Design Projects Craig Larman,...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
19 Analysis and Design Projects © Craig Larman, 1998 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Problem Description--Point Of Sale Terminal (POST) Project 2 © Craig Larman, 1998
Background image of page 2
Development Cycle #1: Problem Description Point-of sale terminal (POST) systems support the checkout sales process. The first POST Development Cycle supports a simplified version of the POST system. Consider the following (intentionally vague) description of use. Please query the instructor for details or to verify assumptions. A customer walks up to the POST checkout with items (e.g., clothes, computers, food, É). The cashier manually enters the UPC (universal product code) from each item. If there is more than one of an item, they can enter the quantity as well. The POST displays the item price and description. On completion of item entry, the cashier presses a key indicating the sale is finished. The grand total is displayed. There are no tax calculations. Payment is in cash, and the sale completes in the “usual manner”. (When a solution is provided, it will express all details necessary to continue). © Craig Larman, 1998 3
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Development Cycle #2: Problem Description The second POST Development Cycle has one additional requirement: different kinds of payments can be received. Credit cards and personal checks are acceptable, but each must be authorized. (Please note that in a real iterative development strategy for a POST there are possibly higher priorities than payment authorization, but this topic motivates understanding some critical object-oriented design skills). Consider these two partial scenarios: Credit card payment Check payment 4 © Craig Larman, 1998
Background image of page 4
Credit Card Payment ... as before. .. The cashier tells the customer the total. The cashier is informed it will be a credit card payment for the exact total. The customer swipes their card through a card reader unit (such as a Verifone). The card reader transmits the card number to the POST. The POST system electronically requests authorization from one of several credit card authorization services depending on the credit card type (Visa numbers start with Ô4Õ, MasterCard with Ô5Õ. ..). There are many authorization services for each card type; a business has a contract with one particular service for each card type. The request involves transmitting a formatted request record of information to the service--card number, merchant ID, sale amount. The format of the record varies depending on the service company, and on the card type. Note that a store may have many merchant IDs; one per authorization service. © Craig Larman, 1998 5
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Credit Card Payment (cont.) Please note that although the record layouts may vary, they all contain the same information. The POST system, after a short delay, electronically receives back an reply record from the authorization
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/29/2011 for the course SEN 632 taught by Professor Aslam-mir during the Spring '11 term at National.

Page1 / 31

Exercises - 19Analysis and Design Projects Craig Larman,...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online