image provider

comparison shopper


This essay does not describe an existing computer program, just one that should exist. This essay is about a suggested student project in Java programming. This essay gives a rough overview of how it might work. I have no source, object, specifications, file layouts or anything else useful to implementing this project. Everything I have prepared to help you is right here.

This project outline is not like the artificial, tidy little problems you are spoon-fed in school, when all the facts you need are included, nothing extraneous is mentioned, the answer is fully specified, along with hints to nudge you toward a single expected canonical solution. This project is much more like the real world of messy problems where it is up to you to fully the define the end point, or a series of ever more difficult versions of this project and research the information yourself to solve them.

Everything I have to say to help you with this project is written below. I am not prepared to help you implement it; or give you any additional materials. I have too many other projects of my own.

Though I am a programmer by profession, I don’t do people’s homework for them. That just robs them of an education.

You have my full permission to implement this project in any way you please and to keep all the profits from your endeavour.

Please do not email me about this project without reading the disclaimer above.


If you were shopping, wouldn’t it be nice, if you could point a little Blackerry like device at the UPC (Universal Product Code) bar code on a bag of coffee beans and see on your screen something like the following:
The Market on Yates
Salt Spring Coffee 400 gram bag
price 9.98
cost per kg 24.95
typically goes on sale every 2 months
nearby store prices 9.90 to 19.00
You could fetch detailed information about the prices at nearby stores if you wanted.

The information would come from a computer database delivered over the EDVO data-cellphone system. But how does the database know this information? Ideally the stores would co-operate and would provide a list of UPC/prices/size/description. But what if they refused?

The people shopping in an area would provide price info as side effect of using the system. For example if the database did not have a sufficiently solid price for a given product at a given store, it could ask the user to enter the price the store was charging. This could be checked for plausibility and consistency with the price registered by other shoppers. Shoppers who consistently lied could be blocked from using the system.

UPC product description information is fairly easy to come by. If any product is missing, again you can ask the users of the system to fill in the holes in your data.

Most fresh produce does not have UPC codes. For that you have codes for a kg of organic carrots, a kg of organic fancy Gala apples and select them from the BlackBerry menu.

You could experiment with the idea using ordinary Blackberries, without UPC readers, but that would be so tedious it would rarely be worth the bother.

What might be possible is to use an ordinary Java-powered cellphone with camera. The camera plus software might be able to read bar codes. You could sell this as an add-on to ordinary cellphones, rather than a dedicated device, perhaps paid for completely by advertising. To try out the idea, before investing in a technological solution, just upload the UPC images to a small sweat shop for transcribing.

Other Services

The device would do other shopping services:
FlowFinity: UPC readers for BlackBerry
UPC database info
UPC databases by email
UPC reader for the BlackBerry

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