EAServer is a middle-tier component transaction server that hosts executable business objects called components. You can access components on EAServer from your Web applications.
EAServer can host various types of components including PowerBuilder objects and Java classes or beans. Although these components have different origins, they have several things in common. They:
Encapsulate business logic that one or more applications need to execute
Shift processing to the middle-tier EAServer server, enabling application clients to remain thin
Are stored in packages and contain methods that clients can call to perform specific operations
Developers typically create components using tools such as PowerJ or PowerBuilder. These tools enable developers to build classes or objects and deploy them directly to EAServer as components. For more information about EAServer, see the EAServer Programmer’s Guide.
You can take advantage of the Web Target user interface to access EAServer components by using:
4GL JSP pages to help you create server scripts that access EAServer components.
Web DataWindow DTCs to let you access Web DataWindow server components available on EAServer. The Web DataWindow retrieves, processes, and displays data on a page, and EAServer manages the database connection.
4GL JSP pages give you quick access to EAServer components by:
Letting you bind page controls to EAServer component properties
Giving your scripts access to EAServer components as represented by variables
Providing drag-and-drop programming access to methods of EAServer components
For more information about 4GL JSP pages see Chapter 9, “Developing 4GL JSP Pages.”
The Web DataWindow DTC provides a design-time interface that lets you select the DataWindow objects to include on a Web page. It also permits you to override certain settings of the DataWindow object before the Web DataWindow displays in the client browser.
4GL Web pages also provide enhancements for Web DataWindow objects available through EAServer. A server representation of a Web DataWindow object (the PSWebDataWindowClass object) allows you to write server-side scripts for DataWindow events and methods. For more information about the Web DataWindow DTC, see Chapter 11, “Using the Web DataWindow Design-Time Control.”
