Browse Prior Art Database

Model for Building and Running AS/400 RPG Programs in a Java Virtual Machine

IP.com Disclosure Number: IPCOM000122997D
Original Publication Date: 1998-Mar-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 5 page(s) / 144K

Publishing Venue

IBM

Related People

Farn, B: AUTHOR

Abstract

A Java Virtual Machine environment allows an application to be written once for running on many different workstation operating system platforms. Existing character-based AS/400 RPG programs are unable to execute within a Java Virtual Machine environment, and are therefore unable to execute on different workstation platforms. A method for building and running character-based RPG programs within a Java Virtual Machine is disclosed.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 47% of the total text.

Model for Building and Running AS/400 RPG Programs in a Java Virtual
Machine

      A Java Virtual Machine environment allows an application to
be written once for running on many different workstation operating
system platforms.  Existing character-based AS/400 RPG programs are
unable to execute within a Java Virtual Machine environment, and are
therefore unable to execute on different workstation platforms.  A
method for building and running character-based RPG programs within a
Java Virtual Machine is disclosed.

      The following modules are required for the building and running
of character based AS/400 RPG programs in a Java Virtual Machine on a
workstation.  The relationship of the modules to each other is shown
in the diagram below.  A Java application or Java applet consists of
the modules at the right edge of the diagram.  The application or
applet modules need to reside and execute within a Java Virtual
Machine.

The software modules required for the building and running of
applications and applets are described below.

      RPG to Java Source Code Translator

      This executable takes existing RPG source code and generates
a Java source code class.  The generated class contains several Java
specific functions:
  1.  "main()" for running as a Java application
  2.  Java Applet class functions for running as a Java applet

The generated code calls functions contained in the set of RPG
Runtime classes which is described below.

      DDS Display File to Java Source Code Translator This executable
takes an existing Data Description Specification (DDS) Display File,
and generates a Java source code display file class.  The generated
class contains information which describes the behavioral
characteristics of  each element in the source display file.  These
elements include:
  o  Files
  o  Records
  o  Fields
  o  Windows
  o  Menus
  o  Subfiles

These classes are used by the set of Workstation Runtime classes
which is described below.

      Java Source Code Compiler

      The Java compiler compiles the Java source code generated by
the RPG to Java Source Code Translator, and the DDS Display File to
Java Source Code Translator, into Java bytecode classes.

      RPG Language Runtime Classes

      These precompiled Java classes handle all RPG language specific
functionality such as opcodes, data types, and indicators.  These
classes are called by the generated RPG classes.  These classes use
the Workstation Runtime classes, and the AS/400 Toolbox classes which
are described below.

      AS/400 Toolbox Classes These precompiled Java classes:
  1.  Handle communication between an AS/400 and a workstation.
  2.  Handle accessing AS/400 databases, database records and
       files.
  3.  Perform codepage translations between the AS/400 and the
       workstation.

These classes are used by the RPG Language Runtime classes.

      Workstation Runti...