The first wave of attention for XML focused on Web services, but it seems that it's really coming into play as a sort of lubricant for allowing data exchange between heterogeneous systems. Is that what you expected?
There is no doubt whatsoever that if you go into an environment where XML is really, truly being used right now, it's that lubricant role you described. It's lightweight, quick and dirty enterprise application integration. The world is a heterogeneous place. Given the pace of mergers and acquisitions and the desire to centralise in the enterprise, there's a lot of big, hard, ugly integration problems everybody faces. And it suddenly became apparent at some point that almost every application, no matter how old, had a Web server on it. And you could achieve remarkably acceptable results in enterprise application integration simply by binding a set of XML messages to ship back and forth. There's just an immense amount of that happening right now.
What about the Web services part, where it seems like it's been more sizzle than steak to date?
It depends what level you talk about. If you want to deploy an application across the Web on a fairly large scale, or if you've got an application you want to deploy across a network, there have been a variety of ways to get the systems to talk to each other -- CORBA (Common Object Request Broker Architecture), Java RMI (Remote Method Invocation), things like that.
The notion of integrating these things based on a loosely coupled exchange of messages, with the messages formatted in XML -- that's clearly a winner and is already being done a lot. In a lot of cases, it's done simply on an ad hoc basis -- a couple of guys got together and decided that this is what they needed. The notion of formalising that and building tool kits around it is fine. So, the idea of Web services is real; something that will pay for itself big time.
Having said that, there is this huge, sprawling stack of standards built on top of standards for orchestration and choreography and routing. And I don't have the slightest clue what some of these guys are talking about. To a certain extent, yes, there are castles being built in the sky.
But the basic materials, like Soap (Simple Object Access Protocol), are deployed in most of the server and client infrastructures. Soap is real. WSDL (Web Services Description Language) -- I don't use it myself, but it certainly works. There's outstanding integration for people who are in the Microsoft world and the Visual Studio .Net environment. If you have a Web service and can write a WSDL description of it, you can pull together a nice application with an amazingly small amount of work on the .Net machine. So, I think there's some real steak there with the sizzle.
