The Remote Procedure Call (RPC) mode allows you to generate specialized Java source for the RPC containing an emulation that accesses a discrete piece of information in a legacy mainframe application.

At design-time, you use the iWay Emulation Adapter (3270/5250) Telnet Designer to connect to a mainframe application, then navigate and capture the application transaction you want to extract. This requires identifying the screens, input fields, and values necessary to access the information you want, and identifying the fields that you want returned by the transaction to the client application. You save this information as an RPC program, at which time you have the option to generate a stand-alone RPC Java program for use on other application servers.

You compile the RPC program to generate an RPC class, which can then be used by the client application at run time. This RPC class is also referred to as a transaction module because it hold the information to perform a specific transaction using an application, for example, retrieving customer account information.

At run time, your client application sends an XML request document containing the RPC class. The RPC class works with the iWay Emulation Adapter (3270/5250) to drive the mainframe application with the required 3270/5250 buffers. In this way, it navigates through the application to the designated data and returns the requested information in an XML document. At run time, your client application can:

• Send information to a mainframe session. Your client application sends the input parameter variables required by your mainframe application in an XML request document.
• Receive information from a mainframe session. Your client application receives the designated output data from your mainframe application in an XML response document.