Portable RPG by converting RPG to Java, and converting Display Files to JavaServer Pages
Original Publication Date: 2002-Aug-01
Included in the Prior Art Database: 2003-Jun-21
Today many business partners, independent software vendors, and customers have 5250 applications written in RPG that run only on iSeries or AS/400 servers. Many have a pressing business need to enable them to run on other platforms. This invention offers a means to facilitate that by leveraging Java and JavaServer Pages. There are two main considerations in such a conversion: the business logic written in RPG IV, and the user interface written in Display File DDS (Data Description Specification). tm This invention converts the business logic to Java(), and the user interface to JavaServer Pages(tm), tm controlled by a runtime Java Servlet(). The database access code in the RPG application would be tm converted to JDBC() Java Database Connectivity. While this does not handle the entire content of a typical application, it does handle the vast majority of it, leaving only a small portion, such as direct access to system services, to be manually converted to a portable alternative. For example, access to AS/400 data queues could be converted to use IBM MQSeries. By targeting and leveraging Java, JavaServer Pages and JDBC, the inherent portability offered by these industry standards will immediately make the RPG application portable, including the business logic, user interface and database access. These are widely deployed and widely used technologies available on practically all platforms. JDBC offers access to most if not all major databases. This invention makes an existing 5250 application portable, by converting the majority of the application to something that is proven to be open and portable. The idea is most easily implemented by leveraging existing IBM technologies. For example, the IBM VisualAge RPG product supports the ability to convert non-interactive (batch) RPG IV logic into Java. The IBM WebFacing Tool can convert display file DDS to JavaServer Pages and JavaBeans, and supplies a servlet and a runtime to derive those converted objects from the original application.