Re: RPG to Java Conversion -- JAVA400-L

Sorry for the delayed response...busy day.

In a nutshell, what we are doing is Servlet/JSP for simple navigation and simple applications with less complex UI requirements. However, the bulk of our effort has been using Swing Applets comunicating XML over HTTP to Servlet(s), which may or may not be using existing RPG logic to return results to the Applet.

A couple of things I didn't point out in the original email were that we are enhancing existing functionality of these legacy applications while moving parts of them to Java. We are not just changing the "presentation layer". Removing 5250 Interactive Tax is a benifit, but not the driving force. We (my company) want to place more importance on an intuitive, yet robust UI. We are a software vendor, and compete with other solutions based on Windows and also Unix. UI is considered a weakness of our system (yes, this is a perceived weakness). We might have been out of business several years ago, if not for Seagull's JWalk product (screen-scraper). I don't like JWalk very much, but it served it's purpose. It gave a better impression to perspective customers than did green-screen. We have passed the limit of the JWalk product, and Java is our next step (albeit large). Applets give us the advantage of a Rich GUI without having to install/deploy/upgrage each and every PC that needs to use the software.

Ken Kennedy

Joe Pluta wrote:

From: Ken Kennedy
My company is going through a transition.  Myself and a few others have
shown them (upper management) what Java is capable of doing, and they
like it.  We are an ISV, and all of our source is CL or RPG.  We are not
looking to move away from the iSeries platform, and we are not looking
to replace major business logic already mature and working.  We are
wanting to replace the presentation layer with Java/HTML.  We have about
35 RPG developers, and 4 Java developers.
My boss wants to review several plans on how we are going to transition RPG developers to Java. Again, we are not wanting to transition all 35 to Java. Do any of you know of any literature (white papers, documents, web sites, etc...) available that outlines this type of transition? Any success stories? Any literature would be appreciated.


Since I sell a product that does exactly this (replace the user interface of
legacy systems with Java/JSP), I am intrigued as to how you plan to
implement your design.  My book on the subject, E-Deployment: The Fastest
Path to the Web, is still available, and gives an excellent review of the
steps required to peel off the 5250 interface and replace it with JavaServer
Pages.  I cal this the server/client architecture, as opposed to
client/server.

If that's indeed what you are trying to do, then you don't need a lot of
Java folks.  Java development is really broken down into two levels: class
creators and class consumers.  Class creators are the folks who write the
hard bits, the plumbing, if you will.  The class consumers then simply call
APIs.

In your environment, you'd need someone to write the interface between the
RPG and the web server, and then you'd need some JSP experts to help you
design the user interface.  In the perfect world, your RPG programmers would
never need to know anything about Java, at least in the beginning, because
they would continue to maintain your applications using traditional green
screen techniques.  A second step would then modify these programs to use
APIs to talk to the web server.

Eventually, you would encapsulate your business logic in true servers that
could be invoked directly by servlets in a client/server architecture (at
which point you would then have a staff consisting of servlet designers who
know Java and business logic designers who know RPG, along with JSP
designers who do the UI portion), but in the meantime the server/client
model would get you to market almost immediately.

Joe


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