Several years ago I was thinking about buying a small gas station in my local town. I went to my friend Gregory Z., a successful businessman in this field, and asked him, "How do I start a gasoline business?" He gave me simple but wise advice: "You know nothing about gas, but know a lot about computers. Keep doing what you're doing. Just be a little better than others".

I'm trying to follow his advice but I keep thinking how would I apply my software skills had I bought such a business. So here I am again asking for your help, advice, and experience: let's automate my virtual gas station.

The Setup
I've borrowed the money from a bank and now I have:

• A four-car gas station
• A small convenience store (coffee, cigarettes, milk, newspapers)
• A repair shop that changes oil, brake pads, and tires
• Six employees: one American, two from India, one from Russia, and two from Pakistan; one employee speaks English, and the others speak well in their native languages. I think they have work permits.
• Three decent Wintel computers
• $1,000 USD software budget

In a perfect world, all service providers use the same protocol, which is as challenging as having all my employees use only the English language. My employees are trying hard, because for them it's a matter of surviving. Initially they are exposing just a minimal number of public services like fillItUp, getCash, processPlastic, marlboroLightsPlease, oilChange, and takeTip. Smarter employees quickly add more services to their vocabulary to become more competitive. Each of these coarse-grained services may consist of several smaller steps, but consumers don't need to know about them.

Service Coupling
When the guy who sold me the business gave me a pile of different forms to use with suppliers, I thought to myself, "Tight coupling in action." I need to know where these suppliers are located, their services, and how to request them. If a particular vendor changes its request form (the protocol), I'll need to get a new one, otherwise I may lose this service. I'd rather be sending a message to some destination saying, "Yakov needs 1,000 gallons of 93-octane gasoline." Expected response: several price quotes from different vendors. This would be an example of decoupled services. I don't know who they are and they don't know who I am, but we've dynamically discovered each other. I've heard that Jini could help me with this. Is this right? Anyway, in a loosely coupled system a service requestor needs to know the name of the service, what data to provide, and what to expect back, but it should be easy to switch from one provider to another.

Messaging and Transport
One of the best ways to request and receive services is by using asynchronous messaging. JMS is an excellent API, but you still need a transport to deliver your messages between the services, for example, message-oriented middleware (MOM). IBM and Tibco offer great MOM products, but I'd need to sell my gas station and get another loan just to pay for it. No, I need to find something for free.

Web Services
Web services seems to be a decent way to arrange my interaction with external suppliers using a free Internet-HTTP-WSDL-UDDI-SOAP combo. If my external vendors will start publishing their gasoline-tires-milk quotes, I'll write a program that will automatically be looking for the best deal in my neighborhood. Can Eclipse IDE help me with automatic generation of all supporting files for Web services?

OOP Plus AOP
It goes without saying that I'm thinking objects (thank you, Bruce). When I close my eyes, I clearly see the classes Product, Order, and Customer…but after reading about aspect-oriented programming (AOP) these objects become blurry. But AOP is a way to go and I'll dig more in this direction.

Storing My Data
I need a free DBMS. It doesn't have to be fancy and implement sophisticated SQL constructs. Inner and outer joins plus indexing will do. Coding business logic in stored procedures is not in fashion these days. Hibernate looks nice for object-relational mapping. Is this my best option?

Front End
For thin Web clients I'm planning to learn AJAX. If Google did it, so can I. How about rich clients? Swing is not there yet; SWT looks better; .NET is the best but isn't free. Should I spend my money on VB.NET? But I don't know VB! Let me ask my Russian employee Alex if he knows it. He looks like a PhD (does he really have a work permit?).

Help
I'd love to hear your input to this new column. You don't need to write any code, but rather suggest some affordable tools and architectural solutions for my small business. Just provide your feedback to the online version of this article at http://jdj.sys-con.com/read/108260.htm.