Using Object Oriented COBOL in a .NET environment

A white paper is available for download from Micro Focus which helps COBOL programmers move further toward the world of object-orientation, and explain some of the features of the ISO2002 standard.

COBOL-2002's object oriented features, as incorporated into Net Express with .NET, permit COBOL to function in the object world more usually associated with other languages like Java and C++ / C#. Interestingly, the actual object oriented syntax additions to the language are relatively few in number but they are profound in functionality. The mastering of them will permit you, for example, to bring COBOL applications into the .NET Framework environment. The white paper introduces you to basic object oriented COBOL (OOCOBOL) syntax and describes how to use it in writing programs to interface between conventional COBOL applications and other .NET language programs.

The paper is designed around a simple file access example that computes shipping and insurance charges for selected inventory items, and while it is unlikely you will be converting many existing COBOL programs to OOCOBOL classes, the exercise serves as an excellent vehicle for illustrating the syntax and techniques you will need in using COBOL in the .NET environment.

You can think of a COBOL class as consisting of two primary components: data and methods (procedures) to operate on that data. Methods have the appearance of a subprogram complete with its own data (which can be local and non-persistent, or global and persistent, depending on its definition).

A method can include all four of the usual COBOL divisions (Identification, Environment, Data and Procedure), and parameters for inter-program communication. Rather than using the CALL statement as you would with a subprogram, for classes an INVOKE statement is used.

Another aspect of using COBOL in the .NET environment is the disparity between data types across different languages. For the purpose of exchanging data between objects created from different languages, the .NET Common Language Runtime (CLR) defines a standard set of data types. Where necessary, Net Express with .NET can transform data from its native data types to the CLR types.

The final example in the white paper shows how to utilize the earlier principles of OOCOBOL to write a COBOL class that can communicate between the existing procedural COBOL application (or subprogram in this example) and a non-COBOL user interface.

For more information about writing such an interface program using OO COBOL syntax, and to download full examples of the OO COBOL syntax and techniques you would need, refer to the white paper Using Object Oriented COBOL in a .NET Environment here.