Appendix F. The LANSA Composer Request Server

The LANSA Composer Request Server provides support for the tightest possible integration between LANSA Composer and other LANSA applications, permitting each to invoke functions in the other, even though they may be executing on different server systems, in different LANSA run-time systems and/or different LANSA partitions, and even if they are running in different versions or EPC levels of the LANSA run-time.

In particular, the LANSA Composer Request Server supports the following:

• LANSA Composer "calling" LANSA
  
  Using the CALL_FUNCTION activity in a LANSA Composer Processing Sequence to "call" a LANSA function on the same or a different server system and/or in a different LANSA system and/or partition and exchange variable information with it.

• LANSA Composer "calling" LANSA Composer
  
  Using the COMPOSER_RUN activity in a LANSA Composer Processing Sequence to run a Processing Sequence in another installation of LANSA Composer on the same or a different server system and/or in a different LANSA system and/or partition and exchange variable information with it.

• LANSA "calling" LANSA Composer
  
  Using the COMPOSER_RUN built-in function in a LANSA application to directly "call" a LANSA Composer Processing Sequence on the same server system in a different LANSA system and/or partition and pass variable information to be used as Processing Sequence parameter values.

 

By and large, the operation of the LANSA Composer Request Server is transparent to users of the system.  The LANSA Composer designer or the LANSA application developer simply needs to provide appropriate parameter values to the CALL_FUNCTION activity or the COMPOSER_RUN built-in function.  If needed, the request will be directed through the LANSA Composer Request Server automatically.

The LANSA Composer Request server works by executing the request in a separate process or job.  This occurs transparently and is managed by the request server to ensure that no conflict is possible arising from attempting to simultaneously use two LANSA run-time systems.

The implementation of the LANSA Composer Request Server is specific to the server operating environment being used.  In other words, LANSA Composer provides two implementations:

• LANSA Composer Request Server for IBM i servers

• LANSA Composer Request Server for Windows servers

 

For the most part, the LANSA Composer designer or the LANSA application developer need not be concerned with any differences between the implementations for IBM i and Windows servers.  However, there are some differences in the constraints and behaviors that may be relevant or important in some cases.  Amongst other things, this appendix documents such differences.

In addition, there are some things you need to understand about the execution context for requests that are processed through the LANSA Composer Request Server.  Furthermore, on IBM i servers, you may need to manually configure the LANSA Composer Request Server for optimal operation in your operating environment.

The following topics provide additional information:

What You Need to Know About Requests Processed Through the LANSA Composer Request Server

How the LANSA Composer Request Server for IBM i Works

How the LANSA Composer Request Server for Windows Servers Works

Connecting to the LANSA Composer Request Server on a Remote System

LANSA Built-in Functions that use the LANSA Composer Request Server

LANSA Programming Considerations for Called Functions

Configuring the LANSA Composer Request Server for IBM i to Suit Your Needs

Troubleshooting the LANSA Composer Request Server