2.1 Oracle Application Server Core ComponentsAt its core, Oracle Application Server consists of three components:
Each component, described briefly in the following subsections, plays a major role in Oracle Application Server operations; they also provide some supporting functionality to their counterparts in various configurations. 2.1.1 Oracle HTTP ServerThe Oracle HTTP Server is the web server for Oracle Application Server. It takes an incoming request in the form of a URI. It then either sends the requested static content ”for example, an HTML file ”directly to the requestor , or reroutes a request for dynamic content, effectively handing off the request, to an appropriate executable resource. The Oracle HTTP Server can process a dynamic request using any of the following:
Chapter 5 describes the Oracle HTTP Server in detail. 2.1.2 Oracle Application Server Containers for J2EEOC4J is a set of J2EE containers and a JavaServer Pages translator that provides a J2EE-certified Java environment that is scalable both horizontally and vertically. You can cluster OC4J instances across hosts ; doing so eliminates both hardware and software failure and provides almost unlimited capacity. You can run multiple JVMs in an OC4J instance to leverage the capacity of hardware with multiple CPUs. Chapter 6 describes OC4J in detail. 2.1.3 OracleAS Web CacheOracleAS Web Cache is an optional component that can play several important roles:
Chapter 7 describes OracleAS Web Cache, as well as the other caches used by Oracle Application Server, in detail. 2.1.4 Core Component InteractionFigure 2-1 shows the relationships among the three main components of Oracle Application Server. As shown in the figure, the interactions among components work as follows :
Figure 2-1. Interactions among Oracle Application Server core componentsAs the figure illustrates, there are additional dynamic processing engines, such as FastCGI, mod_perl , and PL/SQL. The architecture also includes a number of shadow processes, shown in gray, that support the use of Oracle Application Server core components. These shadow processes include:
See Section 2.2.3 for more detailed information on these processes. The configuration data itself is kept in a repository, which is part of the Oracle Application Server infrastructure, described in the next section. |