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SOAP isn't always the cleanest integration model for your applications. Sure, the W3C's Web services architecture has become the de facto approach for getting Microsoft Windows- and J2EE-based applications working together. And you can use the IBM zSeries mainframe server or a similar platform with the Simple Object Access Protocol's XML-based Web services to integrate your intranet architecture.
But your network response time can suffer and CPU usage can spike when you retool your old COBOL-based OLTP applications to Java: If you re-engineer your legacy order-entry application as a SOAP service, it can require as much as 100 percent more CPU use and degrade your response time. And this setup is not as efficient as using Java applications, either.
That's when an alternative to SOAP-based Web services makes sense. One option is Sun's J2EE Blueprints, but this J2EE design pattern's heavy reliance on objects can drag down the throughput of your transactions. Here at QVC, the retailer for which I work, we're deploying a simpler cross-platform XML application architecture-sans SOAP. This XML architecture requires few objects and can be implemented easily inside a Java application or servlet.
Client- vs. Service-Side
XML indeed is becoming the lingua franca among large, disparate, distributed computing environments. Applications receive and generate data in XML format. The integration model we implemented at QVC is a two-tier, client-server model rather than a three-tier one. As with the SOAP RPC model, XML data is sent through the network. But unlike SOAP's, our setup doesn't contain an envelope packed with encoded information for the message and header. The processing overhead with SOAP's XML payload is the W3C architecture's main trade-off: Time-sensitive transaction processing applications don't need that kind of payload baggage.
You can configure the XML-based intranet model to simply send and receive XML messages over the network. Because it uses cross-platform components, such as XSLT (Extensible Stylesheet Language Transformation) processing for creating HTML pages and J2EE application servers, this architecture gives you plenty of leeway in how you configure your processors. That's a big plus. In most organizations, the driving force behind application hosting and configuration is the total cost of ownership-the cost of building, hosting and maintaining an...