NonStop Servlets for JSP System Administrator's Guide

Overview and Architecture

NonStop Servlets for JavaServer Pages (NSJSP) System Administrator’s Guide—525644-001

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Model-View-Controller Designs

JSP page is requested the first time. The result is a JSP page implementation class file

that implements the Servlet interface.

The JSP page implementation class file extends HttpJspBase, which in turn

implements the Servlet interface. The service method of this class, _jspService(),

essentially inlines the contents of the JSP page. Although the _jspService cannot

be overridden, you can effect initialize and destroy events by providing

implementations for the jspInit() and jspDestroy() methods within your own

pages. When the class file is loaded within the web container, the _jspService()

method is responsible for replying to a client request. By default, the _jspService()

method is dispatched on a separate thread by the web container in processing

concurrent client requests.

Model-View-Controller Designs

There are two design philosophies for JSP usage. The approaches differ in terms of

where most of the processing takes place. In the first approach, shown in Figure 1-3, A

Basic NSJSP Model, the incoming request from a web browser is sent directly to the

JSP page that is responsible for processing it and replying back to the client. Content

is separated from presentation because data access is performed using Java Beans.

This approach is fine for simple applications, but requires that all request processing

occur in the JSP page, making each page individually responsible for managing

application state, verifying authentication, and maintaining security.

Figure 1-3. A Basic NSJSP Model

VST904.vsd

JSP

Java Bean

or Java Servlet

CLIENT

BROWSER

WEB CONTAINER

Data Storage

REQ

RES