CSCI 6448

Object-Oriented Analysis and Design

Homework 4: Putting It All Together

Introduction

A small credit union has decided to improve their ability to serve their customers by providing a Web portal that will allow their customers to view their account information on-line and perform simple transactions such as transferring money between accounts. The credit union already has an existing banking application that is used by the credit union's tellers to conduct the business of the credit union. This system makes use of an industrial-strength database to store information about all of the credit union's accounts. The Web Portal is envisioned as a "thin layer" that will integrate with the existing banking system to access the information stored in the database. The Web Portal's main responsibility beyond submitting requests to the banking system and displaying the results of those requests is to authenticate users. Credit Union members can authenticate themselves by supplying their bank account number and a password.

Instructions

1. Write two medium ceremony use cases for the following two scenarios.

a. John logs in to the Web Portal and views the current status of his checking account. (Note: users can have more than one account.)
b. Sally transfers 500 dollars from her savings account to her checking account.

2. Create two activity diagrams (one for each use case) that model the flow of control of these two scenarios.
3. Select an activity from each activity diagram and draw an interaction diagram that shows the objects that participate in that activity. One of your interaction diagrams should be a sequence diagram and one should be a collaboration diagram.
4. Draw a class diagram that contains the class definitions for the objects that participate in your interaction diagrams.
5. Pick two classes from your class diagram and draw two state diagrams for the selected classes.

Evaluation

Your assignment will be evaluated in terms of the quality of your design and the accuracy and consistency of your diagrams. With respect to quality, it would be very easy to make this homework non-challenging, by selecting activities that only require one step, or classes that only have one or two states. If you do so, you will be downgraded. Instead, try to focus on those aspects of the system that require some thought with respect to their design, i.e. how is authentication handled or what happens if the transfer fails, etc. This homework assignment is worth 50 points.

This homework can be turned in via hard copy, fax, or submitted electronically. Please remember that acceptable formats for electronic submission are ASCII, postscript, and PDF. Send ASCII submissions in the body of an e-mail message (not as an attachment). Send postscript/PDF submissions as an attachment to an e-mail message. If you send postscript, be sure to embed any special fonts that you may use directly into the postscript font. (Most printer drivers provide an option to allow you to embed fonts.) Make sure that your e-mail message is clearly marked (as discussed in lecture 1) and that this same information appears in the attached document.

Any questions?

Send questions to <kena@cs.colorado.edu>. Answers to common questions will be discussed in class and/or posted to the class website.