Method for exploiting Java-based logic from an ISPF user-interface (18-Dec-2009)

Method for exploiting Java-based logic from an ISPF user-interface

The problem is accessing Java-based business logic with an Interactive System Productivity Facility (ISPF) user-interface. Although this may seem straightforward, it is difficult because ISPF may be running on an IBM z/OS operating system that does not support Java. This means that ISPF cannot directly invoke Java method calls. An indirect method is needed for ISPF on a non-Java supporting platform to utilize Java on a supporting platform.

Existing products such as IBM DB2 Test Database Generator have tried to solve this problem by using DB2 stored procedures as their method of indirection. The ISPF application makes a call to DB2 through JDBC. DB2 executes the Java (stored procedure) on a platform that supports Java. This solution has three drawbacks; First, it requires DB2 and the setup of appropriate stored procedures. Second, the performance of this approach may be sluggish. Third, the DB2 stored procedures return simple data structures like result sets, but they do not return complex objects.

In order to create sophisticated ISPF user-interface panels by an indirect technique, that technique needs to support the transmission of complex object types.

This technique leverages the concepts of the model-view-controller (MVC) architectural pattern and the service-oriented architectural (SOA) pattern. The following diagram shows the use of these patterns:

To begin with, the model-view-controller (MVC) architectural pattern is used as a framework for describing how the technique works. The...