Summary

Many applications need to interoperate with other applications. Three common scenarios are interoperating with existing transaction programs running on mainframe computers, interoperating with existing messaging applications running on mainframe computers, and interoperating between time-independent applications.

COMTI can be used to build wrapper components for existing transaction programs running under CICS or IMS on IBM mainframe computers. The COMTI Component Builder is used to create wrapper components from data declarations representing the mainframe application's interface. The developer does not need to write any code for these wrapper components; COMTI provides generic components that read type libraries generated by the Component Builder to determine how to communicate with the mainframe application.

MSMQ can be used to build components and applications that interoperate with existing messaging applications running on mainframe computers or interoperate with other time-independent applications. MSMQ provides both an API and a set of Automation components that developers can use to write components and applications to send and receive messages via message queues. One effective way to architect an application using MSMQ is to encapsulate sending messages within a component that exposes an interface with only input parameters for each method, using one method for each type of message sent. For time-independent applications running on Windows NT, a second receiver component is written implementing the same interface but performing the actual work for each method. A listener application waits for messages to be received at the message queue and calls methods on the receiver component to retrieve and process the messages.