Re: Strategic Java Usage/Productivity -- JAVA400-L

Nathan,

I'm often asked in germany to write articles about "Java for rpg programmers" 
and as an answer I started to write about "RPG for Java programmers" or "How 
to write RPG, after you've learned Java". 
But the very problem with this approach is, that the activation group is 
static tied to a SRVPGM / PGM and so you can't control activation of a 
program. 

Dieter

On Freitag, 19. März 2004 18:59, Nathan M. Andelin wrote:
> Dieter,
>
> I wouldn't go so far as saying RPG is an OO language, but implementing OO
> behaviors in RPG is a truly mind expanding experience, and something that
> would benefit Java programmers too.  Java programmers would gain a better
> understanding of what's going on underneath the covers, inside the JVM,
> when objects are instantiated, extended, morphed, and overridden.
>
> Nathan.
>
>
> ------------------------------
>
> message: 3
> date: Fri, 19 Mar 2004 11:12:47 +0100
> from: Dieter Bender <dieter.bender@xxxxxxxxxxxx>
> subject: Re: Strategic Java Usage/Productivity
>
> Nathan,
>
> in my opinion rpg is very limited to "emulate" or even implement OO; I
> agree
>
> that you can write better code with some technics, you mentioned, but java
> is
> much more productiv in this.
>
> some details I would not agree:
> > There are more similarities between ILE and OO languages than most
> > people realize.  For object instantiation in RPG:
> >
> >  Eval myInstance = myClass_New(parameters)
> >
> >  Callp myClass_doSomething(myInstance: parameters)
> >
> > Where myInstance would be a pointer to a data structure containing
> > instance properties, which would be referenced from myClass procedure
> > calls.
>
> The problem here is: you have no qualified naming for referencing methods
> and
> you can't have more than one instance of a rpg programm. For example: I
> have
>
> a rpg implementation of a HashTable (available at my german Freeware page),
> but you can't have two of them in one program!
>
> > For inheritance in RPG, create a new module, either importing and
> > wrapping the procedures in a base module, or create a new module
> > containing just procedure overrides, then bind to both modules.
>
> That's by far not the same, even if you avoid static binding at
> compiletime.
>
> You can't make generic changes as in java and you have 10 times mor code.
>
> > For polymorphism in RPG, define data exports in modules, supplementing
> > procedure interfaces, which alter the behavior of procedures based on
> > data content.
>
> That's not polyymorphism, maybe you are thinking of overloading of methods,
> but this would not be as readable as in java.
>
> > It's true that most RPG programmers wouldn't consider following OO
> > design patterns, unless they first immersed themselves in OO languages
> > for a period of years.  But I returned to RPG for both performance as
> > well as productivity reasons.
>
> There are nearly none open source components in rpg available and I don't
> know
> where you get the better productivity in rpg from???
> I agree with you, that writing well modularuized code in rpg enhances rpg
> programming productivity, but writing java is faster, if you use available
> components.
>
>
> Dieter
>
> > Nathan.
> >
> >
> > ----------------------------------------------------------------------
> >
> > message: 1
> > date: Wed, 17 Mar 2004 11:11:23 -0800
> > from: "Paul Holm" <pholm@xxxxxxxxxxxxxxxxx>
> > subject: Strategic Java Usage/Productivity
> >
> > Nathan/All
> >
> > Thanks for the clarification of your points.
> >
> >  The point I was trying to make is that Java and its OO capability can
> > lead to much much higher levels of productivity than procedural and
> > RPG languages in both utilities and application development projects.
> > I am not an RPG expert so I might be missing something(s), please
> > excuse/correct me if I'm off.  The flexibility and productivity
> > possible via inheritance, polymorphism, frameworks, and interfaces
> > would be very difficult or impossible to match with procedural
> > languages.
> >
> > I agree that performance can be an issue with complex objects but that
> > all depends on the object/framework design in my experience.
> > Frameworks and components; that's where I enjoy spending most of my
> > time, especially since I can't afford to golf daily which is my other
> > passion</sigh>.  Inquiry objects with inherited "maintenance" method
> > for insert, update, delete, copy can carry minimal overhead and the
> > payback is huge in terms of programmer productivity.
> >
> > For example, I built and deployed, an additional inquiry operation
> > which returns a completely generic Java component with inherited but
> > overridable maintenance methods (insert, update, delete, copy) and it
> > performs very well.  This "department" inquiry was developed and
> > deployed in 45 seconds using  a set of Java components.  That's where
> > I think AS400 shops and others can benefit from OO and Java
> > technology.
> >
> > http://www.planetjavainc.com/wow60/runApp?id=298
> >
> > Java methods are attached to the class so even multiple instances of
> > the components have much less overhead than people suspect.  For
> > example, in addition to the inherited maintenance methods, the
> > framework/component also
> > inherits:  MS EXCEL, XML, web services, dynamic field level security and
> > validation, dynamic associations for linking files to other files, column
> > level sorting (black triangles), dynamic column headers, and several
> > other features.  All features inherited, customizable, to any database,
> > on any platform with zero programming effort needed; all in 45 seconds.
> >
> > That's what Java and OO/frameworks can provide.
> >
> > As far as the XML to HTML performance,  I haven't worked with it too
> > much but I imagine having to parse and regenerate the UI on the fly
> > could be expensive;  I don't know enough about that to comment.  Have
> > a good ne. -Paul Holm
> >
> >
> >
> > _______________________________________________
> > This is the Java Programming on and around the iSeries / AS400
> > (JAVA400-L) mailing list To post a message email:
> > JAVA400-L@xxxxxxxxxxxx To subscribe, unsubscribe, or change list
> > options,
> > visit: http://lists.midrange.com/mailman/listinfo/java400-l
> > or email: JAVA400-L-request@xxxxxxxxxxxx
> > Before posting, please take a moment to review the archives
> > at http://archive.midrange.com/java400-l.
>
> --
> mfG
>
> Dieter Bender
>
>
> DV-Beratung Dieter Bender
> Wetzlarerstr. 25
> 35435 Wettenberg
> Tel. +49 641 9805855
> Fax +49 641 9805856
> www.bender-dv.de
> eMail dieter.bender@xxxxxxxxxxxx
>
>
>
> ------------------------------
>
> message: 4
> date: Fri, 19 Mar 2004 06:53:55 -0600
> from: Glenn Holmer <gholmer@xxxxxxxxxxxxxx>
> subject: no SQL error when file is full?
>
> I have a program running on a PC that uses JDBC to do an SQL insert of
> payroll records to a file.  This week it got to a certain point and just
> hung.  Investigation showed that the file was full (i.e. the DDS had been
> compiled without *NOMAX) and we were able to remedy the situation.  But
> shouldn't that have thrown an SQLException?  Is there something I can do
> differently so that it would?

-- 
mfG

Dieter Bender


DV-Beratung Dieter Bender
Wetzlarerstr. 25
35435 Wettenberg
Tel. +49 641 9805855
Fax +49 641 9805856
www.bender-dv.de
eMail dieter.bender@xxxxxxxxxxxx