Standard Web Application Servers Web Logic example essay topic

Middleware Infrastructure The foundation of all integration products (including the more traditional proprietary technologies as well as the emerging Web platform alternatives) is the middle ware bus that provides interconnections and ensures quality of service. Historically, the industry has selected industry-standard middle ware (either Java 2 Enterprise Edition/ [J 2 EE] or. NET-based) for developing and hosting Web applications, but proprietary middle ware for integrating those applications. But the promise of Web 2.0 is based on convergence to a single unified platform that does both. As a result, the standard Web application servers (Web Logic, Web Sphere, . NET, etc.) are displacing proprietary integration middle ware: it turns out to be a lot easier to extend standard Web application servers to do integration than it is to remake proprietary integration brokers into Web-standard application servers.

(Note: The fact that most of the historically proprietary integration vendors are now including application server technology within their next-generation integration solutions is more compelling evidence for this convergence. The challenge for those vendors, of course, is that this is the "home court" that the Web application platform leaders [BEA, IBM, Microsoft] staked out years ago.) Web services and adapters link the Web integration platform to other applications and data sources. While the middle ware layer is colored green (meaning that J 2 EE and. NET are now safe bets), this layer is a mix of red and green since the essential Web services standards are still being fleshed out. It is clear within this core the technologies that Web Services Interoperability (WSI) validates in its basic profile. Today inter-container interoperability for Web services should likely be restricted to the WS-I basic profile of XML Schema, SOAP 1.1, and WSDL 1.1.

By venturing outside the scope of what we vendors are ourselves testing, you are likely to encounter interoperability issues between different containers -- e. g., between Web Logic and. NET. Intra-container interoperability, however, should not be an issue for the newer Web service standards. An XML-based schema language, typically XML Schema, is the preferred choice for Web service payloads. If XML Schema is becoming a lingua franca for interoperable business objects, then the Simple Object Access Protocol (SOAP) is the framework of "compos able" message headers for defining ever higher qualities of service for passing those business objects between applications (e. g., security, guaranteed delivery).

With Web services, programmers should be careful not to "hard wire" schemes to the business logic so as to achieve the looser coupling that made the Web so successful. Unfortunately, loose coupling is not inherent in Web services -- you must program for it. (Note: Loose coupling works on the Web in the sense that a Web site can undergo dramatic change [say a migration from. NET to Java] without affecting the end users [who may not even notice ASPs turning into JSPs]. Web services loose-coupling is fundamentally harder to achieve. The Web client [browser] and schema [HTML] are fixed, while both sides of the Web services "wire" are expected to accommodate change independently.) In particular, it is recommended that if you use Java as your Web services "design center" (that is, you auto generate Web Services Definition Language [WSDL] from Java classes), you should use "wrapper" classes rather than directly exporting application objects.

Specialists also recommend that customers leverage the extensibility model of XML Schema, and use higher-level bindings like XML Query and "schema compilers" such as XML Beans, JAX-B, and JAX-RPC. Developers can thereby ensure that application changes will be less likely to break Web service interfaces and interface changes will be less likely to break applications. Above the basic profile defined by WS-I are specialists proposals for the standards that will complete the Web services core. WS Security provides selective encryption (privacy), non repudiation, and support for delegation (propagation of security context).

This emerging OASIS standard is poised to be the "SSL" of Web services.