IBM Version 5 XML based Enterprise application architecture, Multi-tier solution architecture

10.1 XML based Enterprise application architecture

Most of the contemporary Enterprise Edition (J2EE) applications rely on HTML for the presentation layer. This minimizes the benefits provided by the flexibility of the distributed multi tier J2EE, since the target audience is limited to users of Web browsers. As the pervasive world is widely evolving, future audience will be the users of new devices. Accordingly, we need to decouple content from presentation logic and become independent of the audiences’ devices. XML’s Web publishing capabilities are the key solution for providing that level of isolation. XML’s Web publishing capabilities are available using XSLT to transform XML documents into other textual documents, compliant with the desirable target devices. The focus of this chapter will only be on using XSLT to transform XML to HTML, but you can use XSLT to transform XML to any desirable markup language, for example WML, VoxML,.etc.

The J2EE layered architecture, illustrated in Figure 10-1, can minimize the cost of evolving an application’s functionality and updating its implementation technology. These layers can be broadly categorized as the client layer, the Web tier layer (which includes the controller servlet, validation logic, presentation data, and presentation logic), the app server layer, and the data server layer.

Client

HTML

	Web Tier
	Validation Logic
Servlet	Request Handler

AppServer

Business Logic

(EJB)

Presentation

Data

XSLT Processor

XML

XSLT

Data

Object

FC

Data

Presentation Logic Data Server

Figure 10-1 Multi-tier solution architecture

216 The XML Files: Development of XML/XSL Applications Using WebSphere Studio