Understanding how a ZIETrans application works

To understand the purpose of the customization techniques described in this chapter, and how they work together, you must first understand how a ZIETrans application processes a host screen to convert it to a GUI. When a user accesses a ZIETrans application, a request is sent to the ZIETrans application, running on a WebSphere® Application Server. The ZIETrans application forwards the request to the host application and receives a host screen. The ZIETrans application transforms the host screen, using the customization you have created in the ZIETrans project, and sends the transformation to the user. Each time the user interacts with the ZIETrans application, the process is repeated.

The ZIETrans application uses a rules-based approach to determine how to convert each host screen. ZIETrans applications can contain a list of screen events (screen customizations and screen combinations), which specify criteria used to match host screens. Each screen event also lists actions to be taken when a match is found. Your ZIETrans application compares each host screen to its ordered set of screen events, and when the first match is found, it performs the specified actions. You do not have to specify how to convert every single screen from your host application. If there is no matching screen event for a host screen, ZIETrans performs the actions defined for the unmatched screen application event, which by default applies the default transformation. See Working with screen events for more information.