Chapter 1: Introduction

This chapter introduces you to the concept of extending existing CICS and IMS applications.

You extend a CICS or IMS screen application by providing access to it from outside the boundaries of a TN3270 terminal or emulator via a Java, .NET, or Web service interface. Similarly, you extend a CICS commarea application by providing a customized interface to the commarea. You can provide access to all of the functionality of an application, or you can create one or more interfaces for specific pieces of an application. For example, if by design your application includes large amounts of information irrelevant to the common user, you can create a service interface that includes only the relevant information. Also, if information relevant to a certain type of user is found on more than one screen, you can create an interface that consolidates the information.

A service interface is a mechanism for accessing an application running under Enterprise Server. It is a collection of input and output fields of a particular format used to communicate with the application via a particular protocol. The most common way to extend a CICS or IMS application is to create a service interface for it using the fields available from its BMS or MFS screens. You can also extend a CICS application without BMS screens via the fields defined in its commarea.

You can create the following types of service interfaces for CICS and IMS applications:

Web service interface
Java interface - either an EJB or a Java Bean
.NET interface

CICS and IMS applications run under Enterprise Server with Mainframe Transaction Option ( ES/MTO). You extend the application using the Interface Mapping Toolkit. CICS and IMS extension entails:

Configuring an enterprise server to run the application under MTO
Adding screens to a service interfaces group
Creating a service interface
Deploying the service interface
Generating a client

You can also optionally capture a workflow to use as a starting point for a service interface. This process from start to finish is documented in the remaining chapters of this book.