Wooden Nickels

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The first thing you should know about XML is that XML is not hard. It is not difficult to learn. In its bare essence, XML is a programmable, hierarchical text file formatthat's all. It will not cure cancer or walk your dog. It's simply a technologya very powerful technologythat people are using to enable applications to work together and share data. It is not hard, and its syntax isn't even that complex, as you'll see in just a moment.

That said, XML does seem to be in a constant state of fluxits creators just can't seem to leave it alone. I'm reminded of what the French film director Marcel Pagnol once said, "One has to look out for engineersthey begin with sewing machines and end up with the atomic bomb." XML's extensibility has led to a dizzying array of initiatives based on it. It seems there's a new XML- related W3C draft specification or recommendation published every week. Just when you think you have your arms around the technology, a new XML application drops out of the sky that addresses a new problem you hadn't thought of, or addresses an old problem in a new way. How does one stay up with all this? How can you possibly make time to master all these XML technologies when all you want to do is share data between your company's SQL Server database and your supplier's UNIX order tracking system?

My advice? Relax. You don't need to know every XML application or technology in order to use XML for its primary purpose. The primary function of XML is to provide open data exchange between platforms and applications. An understanding of XML's purpose and syntaxneither of which is difficult to graspis all you need to use XML productively. The nice thing about XML is that technologies based on it, which are referred to as XML applications, are built with XML itself. So if you can read XML, you can read an XML style sheet, even if you've never seen one before and don't have the foggiest idea of what it will be used for. Of course, reading is one thing; understanding is another. Being able to read English doesn't mean that one can understand a physics textbook written in English. That said, most of the core members of the XML family of technologies are not difficult to grasp, even though they are capable of performing some very complex tasks .

My second recommendation is this: Don't let anyone sell you any wooden nickels, as my grandfather used to say each time I left his home. In the gold rush-like fever that has surrounded XML since it was first introduced, a number of XML "experts" have come out of the woodwork offering their services to the unwary. What they were doing before they became XML experts is anyone 's guess, but oftentimes it turns out to have had little to do with the Web or even technology in general. Be very careful of this. Interest in a technology is not the same thing as expertise in it. Enthusiasm is good; experience is better. I'm enthusiastic about the NBA, but that doesn't qualify me to coach. If a person claims to be an expert in a particular technologyXML or some otherbut hasn't actually used it to build anything, I'm not interested. You cannot master XML by studying W3C recommendations or reading MSDN. Sure, researching a technology to improve your knowledge of it is important. Of course it is. That's why you're reading this book. Read voraciously. Don't stop with W3C recommendations and MSDN. Read everything you can get your hands on regarding XML. This will only advance your overall knowledge of it. But to master any technology, you must use it, and I don't mean to build toy applications or strawman examples. To viscerally know something as broad and as deep as XML, you must build things with itreal things, complex things, useful things.

The situation reminds me of the early days of Java, during which it seemed there was a Java expert on every corner. It was cool to know Java. Java was the new "thing." The book Teach Yourself Java was outselling Stephen King (!), and Java was in the media more than any programming language had ever been. User groups were formed , seminars were conducted , books were writtenJava was taking over the world. There was just one problem. Most of the people extolling all the virtues of Java to do everything from create safer programs to bring back the dinosaurs had never built anything of any significance with it. It was too new. How can you be an expert on something that just came out yesterday ?

Since then, the overall level of expertise in the Java community has improved dramatically. Real Java applications are being built all over the world. We now have several years of experience with it under our belts. Now we really know what Java can do and what it cannot, what it does well and what it does not do so well. And Java itself has evolved. There's a whole new crop of Java experts, but these aren't the same people who were on the street corners five years ago. These are the old hands of other languages, the veterans who took a look at Java and realized its immense potential if used properly. They didn't dive into Java the moment it came out because they know better than to adopt a technology just because it's new or is the latest fad. They waited a little, let the standards settle a bit, then began studying Java to see whether it was any better at tackling the problems they'd been addressing for years with language like C++. Many determined that Java could improve the way they built applicationsthat it was an improvement over the old ways of doing thingsand so they joined the revolution. This is how intelligent adoption of technology should work: It should not be based on fads or a desire to strike it rich. It should be based on experience, data, and reasoning that tells us that the technology in question is enough better than the technology we're using to justify its adoption, to make the overall price of putting it in place near zero because its benefits outweigh its costs.

So, be wary of the snake oil salesmen out there. If someone tells you XML is difficult to learn (and, therefore, you need their expensive consulting to help you understand it), rundon't walkthe other way. If they claim to be experts, but don't have the references to back it up, slam the door. Remember: Enthusiasm is good; experience is even better. There are two kinds of technologists in the world: those who aspire to technical prowess in some area but are not willing to put in the hours necessary to acquire it, and those who love their craft and work diligently everyday to hone it.

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