Three-Tier Application Logic

In this section:

Distributing Processing Among Platforms

Reference:

Partitioned Application Files and Servers
TIBCO WebFOCUS File Types

The three tiers of application logic in a published application are designed to exploit the capabilities of web processing and enhance the performance, scalability, and maintenance of an application. Partitioning an application into tiers is a means of classifying the functionality of the application. You can publish partitioned components across many different platforms. See Distributing Processing Among Platforms.

The three tiers of application logic are:

Presentation layer, which is commonly known as the user interface, or the front end of an application. In a WebFOCUS reporting application, the presentation layer consists of webpages (including HTML files, Cascading Style Sheets, JavaScript™, Java classes, and images).
The presentation layer resides on the web server and is handled by the web server and the web browser of the end user.
User interface logic, which is any application logic other than presentation or data access logic. User interface logic allows you to create and manipulate the components of a report. The WebFOCUS Servlets program is configured to provide the user interface logic. An example of user interface logic is the WebFOCUS Servlet that powers OLAP.
This logic is provided by TIBCO WebFOCUS®, and resides on the Application Server or servlet engine plug-in to the web server.
Data access and formatting logic, which retrieves information from a data source. Data access logic contains the metadata that defines the data sources your applications access. It consists of Master Files and Access Files. Formatting logic consists of the procedures (focexecs), WebFOCUS StyleSheets, certain customized HTML files and embedded graphics, developed by knowledge workers using WebFOCUS. These application objects display reports or graphs, or perform more complicated processing based on values that the end user supplies.
Data access logic usually resides on the same server as the data itself (either the TIBCO WebFOCUS® Reporting Server or a sub-server). A WebFOCUS reporting application takes advantage of the data access logic of WebFOCUS middleware technology.

For an illustration, see Partitioned Application Files and Servers.

Reference: Partitioned Application Files and Servers

The following diagram illustrates how all user interface logic and data access logic can be configured behind multiple firewalls for maximum security.

The web server processes the webpages that provide the presentation logic for a WebFOCUS reporting application. The web server accesses HTML files, graphical image files, and Java class files, and Cascading Style Sheets. For more information about how to specify file locations on the web server, see the WebFOCUS installation guide for your platform.

The application server provides the user interface logic for your WebFOCUS tools, and is the location for servlets, JSPs, and Java Beans. Having an application server to process application logic behind the user interface provides performance and security benefits.

WebFOCUS does not provide an application server. You can use a third-party server, such as WebLogic, WebSphere, Tomcat, Apache, or Netscape.

The Application server resides separately or together with the web server.

The WebFOCUS Reporting Server processes the procedures containing the user interface logic for reports, as well as the files that contain metadata for the data sources. Stored on the WebFOCUS Reporting Server are report requests, WebFOCUS StyleSheets, customized HTML pages called from WebFOCUS procedures, and Master and Access Files.

The WebFOCUS Reporting Server also accesses the data sources used by an application.

Reference: TIBCO WebFOCUS File Types

A WebFOCUS reporting application can publish and use all of the following types of files. The following chart includes file extensions used by the Windows® and UNIX® operating systems. See Defining and Allocating WebFOCUS Files for comparable information for z/OS® and other supported operating environments.

File Type	Description	Location After Publishing	File Extension (Windows/UNIX)
Webpage	Includes files displayed for the end user through a web browser, such as HTML files, graphical images, Java executable objects (class files), and Cascading Style Sheets.	In web server home directory or in web server alias	.htm .html .jpg .gif .css .js .class .jar
User interface logic	Includes servlets and JSPs.	Application server	.jsp .class
Procedure	Includes files that contain the executable functions of an application: report requests, WebFOCUS StyleSheets, and customized HTML called from WebFOCUS procedures using the Dialogue Manager command -HTMLFORM. For details about this command, see Enhancing an HTML Webpage With a Procedure.	On the path of the WebFOCUS Reporting server	.fex .sty .htm
Master File Access File	Includes all Master Files and Access Files.	On the path of the WebFOCUS Reporting server	.mas .acx
Data source	Includes all supported data sources types.	On the platform with the WebFOCUS Reporting Server or sub-servers	n/a
Temporary file	Includes data extracts, temporary files that your application creates during processing, and temporary work files that WebFOCUS uses internally.	In the EDA temporary directory (default) or a user-defined EDA location	.ftm or other requested extension

Distributing Processing Among Platforms

WebFOCUS applications are capable of distributing processing over many platforms, with the following advantages:

You can access data on multiple platforms, thus forming relationships among disparate data sources.
Each component runs in the most suitable environment. For example, a WebFOCUS HTML front-end may run on a Windows or UNIX platform managed by local departmental administrators who authorize and group users, while the data access routines run on a z/OS machine capable of securing the data and aggregating it quickly.
You can speed up your applications. Procedures that access data can run on the platform where the data resides, thus ensuring that any aggregation or screening takes place immediately. This means that your application is not shipping large quantities of data across a network to be aggregated or screened somewhere else. Less network traffic means increased application speed.

For a more detailed discussion of this topic, see the WebFOCUS installation guide for your platform.