The Link3270 server adapter enables a service requester to conduct an interactive BMS request and reply dialog with 3270 application programs that are running in CICS by using the CICS Link3270 bridge mechanism.
3270 emulation and navigation logic for 3270 application screens are contained within the Service Flow Modeler, and are generated as a Link3270 server adapter. This server adapter can comprise the complete adapter service generated by a flow that conforms with the single connector simple pattern, or it could be one of many server adapters that comprise the adapter service generated by a flow that conforms with the aggregate connector complex pattern.
Typical 3270 application programs use CICS Basic Mapping Support (BMS) commands, such as SEND MAP and RECEIVE MAP, to communicate with the terminal user. The BMS commands reference a BMS symbolic map, that contains field data. For a non-3270 terminal client, the Link3270 server adapter provides a virtual terminal environment for the 3270 application, by intercepting BMS and terminal commands issued by the application.
In a web environment, the application program communicates with a Java™ client instead of a 3270 terminal. The application program remains unchanged and continues to use a BMS symbolic map as an interface to the Java client.
Link3270 server adapter logic is developed from the point of view of an end user sitting at a 3270 terminal. That is, the server adapter sees the business response data of the target 3270 application that the 3270 terminal user would see on the screen. However, instead of using a screen of data, the server adapter views the BMS symbolic map, or application data structure (ADS), used within the target 3270 application program. The Link3270 server adapter also indicates which attention identifier (enter or function key) was pressed, and can optionally indicate which field the cursor was in when the key was pressed.