You can work most easily by customizing a JSP file and creating the PageHandler in Page Designer; for details, see Page Designer support for EGL.
The PageHandler itself includes variables and the following kinds of logic--
The PageHandler part should be simple. Although the part might include lightweight data validations such as range checks, you are advised to invoke other programs to perform complex business logic. Database access, for example, should be reserved to a called program.
When generating a PageHandler, EGL never overwrites a JSP file.
All data tables and records that are used by the part handler are also generated.
If the JSP-based JSF tags perform data conversion, validation, or event handling, the JSF runtime does the necessary processing as soon as the user submits the Web page. If errors are found, the JSF runtime may re-display the page without passing control to the PageHandler. If the PageHandler receives control, however, it may conduct a set of EGL-based validations.
The PageHandler field property validationOrder defines the order in which both the individual input fields are edited and the field validator functions are invoked.
If no validationOrder properties are specified, the default is the order of fields defined in the PageHandler, from top to bottom. If validationOrder is defined for some but not all of the fields in a PageHandler, validation of all fields with the validationOrder property occurs first, in the specified order. Then, validation of fields without the validationOrder property occurs in the order of fields in the PageHandler, from top to bottom.
If the EGL runtime finds an error outside of a validator function, the JSF runtime code re-displays the same Web page with embedded error messages. If a validator function finds an error, the function can forward control to another Web page, but the default behavior is to re-display the same Web page.
This section gives a technical overview of the runtime interaction of user and Web application server.
Related concepts
References to parts
Web support