Outcomes Addressed

understand and apply object-oriented design patterns
understand the use of UML in the design process
be able to design and implement small software components and systems
be able to use computer-aided software engineering (CASE) tools in the design process
be able to work effectively as a member of a small team

Overview

Apply the Observer Pattern to the design of an application that monitors the price of products on Amazon.com. Users must enter the ASIN (Amazon Standard Identification Number) for one or more products whose price they wish to track. The program will provide multiple views of the price information. Each of these views should be updated whenever a price change occurs.

You must work with a partner.

Problem Statement

Your program should ask the user to enter one or more ASINs for items whose price they wish to monitor. The program will then monitor the price(s) of the product(s) and update the following views of the data when appropriate:

Percentage discount. Includes: Product name, Product image (optional), ASIN, List price, Amazon.com's current price, Dollar amount saved, Percentage discount, Date/time of price change.
Price change. Includes: Product name, Product image (optional), ASIN, Amazon.com's current price, Percentage change in price since last price change, Data/time of price change.
Price graph. Includes Product name, Product image (optional), ASIN, highest price, lowest price, and a graph of the price (y axis) over time (x axis).

Implementation Notes

Your solution must make use of the Observer Pattern.
You may use the java.util Observer Pattern functionality or implement your own (be sure to explain your choice in your report).
You may implement the price graph view as a listing of all the price changes (along with date/time for each change) instead of creating a graph.
I have provided a simplified view of Amazon.com's product pages to make it easy to extract the product pricing information. These pages can be accessed by using the following URL: http://amazon.t-a-y-l-o-r.com/o/ASIN. For example, http://amazon.t-a-y-l-o-r.com/o/ASIN/0596007124 will display the useful price monitoring information for the Head First Design Patterns book.
You must write a scraper that retrieves pricing information from the internet. You may determine pricing information from Amazon.com's website or make use of simplified product pages I have provided.
Your ConcreteSubject class should have a setPrices method similar to the setMeasurements method in the WeatherData class discussed in lecture. This is required so that you can simulate price changes in order to test your code and demonstrate successful operation.

Sample Results

You should show sample results of your program by simulating the following price changes:

The user indicates that (s)he would like to monitor the following ASINs whose prices are given for Sat Jan 01 00:00:01 2005 UTC:

ASIN	List Price	Amazon Price
0596007124	$44.95	$44.95
B0002CSBH0	$18.00	$17.99
B00005OWCU	$229.99	$208.99
B0007KVOQW	$24.99	$22.79
B00005QFK6	$8000.00	$6000.00
B0006856F0	$429.00	$389.00
B000BO84EE	$24.95	$24.95
B000659OJW	$35.00	$35.00

Price updates occurred as follows:

ASIN	Date	New Price
B0002CSBH0	Wed Jan 12 21:08:18 2005 UTC	$15.39
B0002CSBH0	Tue Feb 01 13:18:18 2005 UTC	$18.00
0596007124	Mon Feb 14 20:55:20 2005 UTC	$28.32
B0007KVOQW	Sun Feb 27 21:24:25 2005 UTC	$24.99
0596007124	Fri Apr 01 13:08:23 2005 UTC	$59.44
0596007124	Sat Apr 02 13:07:15 2005 UTC	$44.95
B0007KVOQW	Mon Apr 18 11:45:17 2005 UTC	$24.99
B00005QFK6	Thu Apr 21 14:32:37 2005 UTC	$7000.00
B0007KVOQW	Fri Jun 24 14:44:45 2005 UTC	$2.49
B0007KVOQW	Mon Jun 27 10:57:59 2005 UTC	$20.99
B000BO84EE	Wed Jun 29 16:17:07 2005 UTC	$20.95
B000BO84EE	Tue Jul 05 09:21:42 2005 UTC	$24.95
B00005QFK6	Thu Sep 01 03:22:32 2005 UTC	$5499.95
B0006856F0	Thu Sep 01 11:17:41 2005 UTC	$339.00
0596007124	Tue Sep 20 01:16:00 2005 UTC	$28.32
B0002CSBH0	Sat Oct 15 23:10:46 2005 UTC	$20.19
B00005QFK6	Sat Oct 15 11:15:39 2005 UTC	$6000.00
B0006856F0	Sat Oct 15 16:15:33 2005 UTC	$389.00
0596007124	Mon Dec 26 08:09:16 2005 UTC	$40.95
B0002CSBH0	Thu Jan 12 04:14:18 2006 UTC	$16.20

Intermediate deliverable (one hour prior to the to week 4 lab)

At the beginning of the week 4 lab period, you should be ready to:

Provide hardcopies of your UML class diagram(s)
Demonstrate your program's ability to retrieve relevant pricing data from the internet and display the results in the "Percent discount" view. (This does not need to be implement using the Observer pattern for this demo.)

Also, be sure to log the time you spend on this project in the FAST system (logged for week 3).

Lab report (due 11:00pm, the day prior to week 5 lab)

Here is a template file to use as a starting point for this report.

Note: All .png images should use the following naming convention:
2811MSOEloginL2x.png
where MSOElogin is the login name for one of the team members and x is a letter.

The lab report (one report for each team) should consist of the following:

Design
- Assumptions made in the design process
- Defense of the decision to use or not use the Java provided observer mechanism
- Class Diagram(s) (.png image(s) of the EA diagrams)
Reactions and Suggestions
- A discussion of how you worked together as a team
- Lessons learned
- Mistakes made while completing the lab assignment
Be sure to log the time you spend on this project in the FAST system (logged for week 4).
Sample results: Include all three views for the final update for each product being watched.
The documented source code for your program.

As with any report you submit, correct spelling and grammar are required. In addition, your report should be submitted electronically following the Electronic submission guidelines. (You may wish to consult the XML help video and/or sample report before submitting your report.) Be sure to keep copies of all your files, in case something gets lost.

Acknowledgment

This laboratory was developed by Dr. Chris Taylor.