A Real Java Project

[Guest.Visitor]

Has anyone been involved in creating a real java project on OS/400? What were some of the problems you encountered? What application did you use to create the client?

[J.Pluta]

In honor of Bill Clinton, it depends on what you mean by "real", "Java" and "on the AS/400". I've written some pretty serious clients that use Swing and communicate directly with the AS/400 database. Right now, I am prototyping a major software application's move from green-screen to web-based applications. This application will use JSP and servlets to replace display files without requiring major rewriting of the application logic. For Swing development, I use Visual Age for Java, while for the JSP/Servlets you can use any decent HTML editor. I have not done any major server-side Java (that is, Java programs running on the AS/400 that perform business logic). src="//www.zappie.net/java/_derived/index.htm_cmp_zero110_vbtn_p.gif" width="140" height="60" border="0" alt="Java400.net - Java/400 Freeware" align="middle"> Java400.Net - where the AS/400 speaks Java with an RPG accent Home of PBD1.2, the FREE Java/400 Client/Server Toolkit href="//www.plutabrothers.com">www.plutabrothers.com

[J.Pluta]

Just an update: we've successfully moved both a single-screen and a subfile prototype to the web. We used the "Redeployment" model, and it was wonderfully successful. We frist split the programs into user interface and business logic on the AS/400, thus preserving the original green-screen environment, then wrote JSP/servlet code to replace the green-screen, thereby creating a web interface to the same business logic. The code is simple, the architecture clean and the performance fantastic (sub-second response time on subfile rolls). I'll post a lot more about this when I get home. src="//www.zappie.net/java/_derived/index.htm_cmp_zero110_vbtn_p.gif" width="140" height="60" border="0" alt="Java400.net - Java/400 Freeware" align="middle"> Java400.Net - where the AS/400 speaks Java with an RPG accent Home of PBD1.2, the FREE Java/400 Client/Server Toolkit href="//www.plutabrothers.com">www.plutabrothers.com

[Guest.Visitor]

Do you reproduce message subfile functionality in Java, including cursor-sensitive help on line 24?

[J.Pluta]

Actually, Gene, I don't reproduce ANY user interface features in Java. This interface is strictly HTML, which means it will run on any browser WITH ABSOLUTELY NO ADDITIONAL CLIENT-SIDE CODE - not even a JVM. In fact, it will run with Lynx, which is a character-based web browser. The HTML-only approach is what makes it so wonderfully fast. There is Java code in the servlet, of course. Not as much as you might expect, but there is some. The code is primarily involved with getting the data out of and back into the EBCDIC buffer received from the AS/400. I'm currently designing the interface to support attributes like color. Data formatting and validation are on the list as well. I plan on having the whole shebang put together in November. The message subfile can be supported quite easily - it involves changing the program that sends a message to the program message queue to send it to the servlet instead. As to "cursor-sensitive help", well, that's something that HTML doesn't do particularly well. I haven't decided on my approach yet - I can either use rollovers or a hyperlink to a "message help" servlet. There are things that won't be supported, of course. More sophisticated 5250 techniques such as user-defined data streams and the like won't be supported by my techniques. Pop-up windows don't "pop up" the same way; HTML isn't made for that (they show up as a separate page, then return to the previous page). But in general, if you used normal display file techniques, this architecture will move you to the web. It takes about a week to teach, and then a decent programmer can convert several programs a day. www.java400.net, where the AS/400 speaks Java with an RPG accent Home of href="//www.zappie.net/java/techniques/pbd.htm">PBD1.2P, the color=red>FREE Java/400 Client/Server Toolkit

[Guest.Visitor]

My real Java Project has been to write a source code editor I could use to edit RPG code. One of it's features is an interactive code indenter/unindenter and well as provide a printer class to list the source in nice 60 line pages with page numbers and headers. After many false starts because I was learning Java and Sun kept changing the language the editor was finished in all its AWT glory. So far so good except the wersion that ran under win95/98 did not load text areas the same as the same as the Blackdown Linux version... This flaw has been corrected in the swing version. The only problem being, that swing fights with AWT and the various classes have had to be re-written. My editor is a work in process because now that I control the source code, there are a vast number of features I just have to add. If you want to view the AWT source, go http://world.std.com/~cogito . Regards Tom Birchmire

[Guest.Visitor]

This comes under the heading of FYI without my comments. At a recent user meeting entitled JAVA for RPG Programmers, one user complained that his project was thrown back three calendar (as opposed to man) months due to lack of a stable JAVA work environment. The constant complaint was constant change. BTW, the JAVA 3 Professional update (VA for JAVA) has just been released, for all who have JAVA 2 Professional. Dave

[J.Pluta]

What has been unstable about the Java environment? Other than the unfortunate name change of com.sun.java.swing to javax.swing (which is now over a year old), the core Java language has been remarkably stable. What many people seem to misunderstand is that, while Java is indeed progressing in leaps and bounds, you can write for today's Java with a pretty good certainty that it will work on tomorrow's Java. For example, I insist on writing all my code to JDK1.1.8/Swing1.1.1FCS simply because that's binary compatible with the current OS/400 JVM. However, when I switch over to JDK1.2 or JDK1.3 sometime next year, NOT A SINGLE LINE OF SOURCE WILL CHANGE. What is instable about that? Java is nearly as stable from release to release as the AS/400 (even more in some cases... anybody seen the WRKSYSACT command lately? Seems to have been "deprecated", although nobody told us). Ah well, I continue to write really cool fun code. My display file emulation is almost ready for its first release, and it supports BOTH thick and thin clients. Way, way, way cool. src="//www.zappie.net/java/_derived/index.htm_cmp_zero110_vbtn_p.gif" width="140" height="60" border="0" alt="Java400.net - Java/400 Freeware" align="middle"> Java400.Net - where the AS/400 speaks Java with an RPG accent Home of PBD1.2, the FREE Java/400 Client/Server Toolkit

[Guest.Visitor]

Tom, have you looked at RPGalive.com ?

[Guest.Visitor]

RPGalive appears to be a super product. However I'll continue development on my own stuff as the experience with the development of a real Java project is really what I'm about. Thanks for the URL Regards Tom Birchmire