Re: Real world Java Scenario (was RE: IBM pushing Java)

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

Hello Brad,

You wrote:
>Scenario JavaScenario = new Scenario():
>
>try {
>You've just created a Java app (with swing) that lets the user view order
>status information.  you have 30 users you want to give the program to.
>
>Questions QuestionsforJavaGuru = new Questions(4);
>  
>1. What are the steps to do this? 
>2. What happens when you make a change to the java app? 
>3. A new Version of java or swing comes out.  You want to use it.  What
>then?
>4. Now, add 10 more plants located in different locations througout the
>united states with 30 users each.  How does this affect 1-3?
>
>This is real world stuff that we all already know how to do with RPG.
>
>Let's hear from the Java gurus on this one.  I'd be interested.
>}

Very cute!  I'm not yet a Java guru (but I'm working on it).  How about:

public class Application extends BusinessRequirements implements MagicUpdate
{
        public void Application()
        {
                if (this.versionLevel != Host.versionLevel)
                {
                        updateLocalApplication( Host );
                }
        }

        private void updateLocalApplication( AS400 anAs400Connection )
        {
                MessageBox.display("Please Wait. Local application being 
updated");
                VersionManager.suckNewAppFromHost( anAs400Connection, this );
        }
}

Now seriously; Assuming a Java application rather than an applet then you use 
Workspace on Demand or 
WiseManager from Serenity Systems and download the user's desktop from the 
server whenever they boot (27 
seconds in the case of WiseManager but that's not over a dial-up line).  That 
takes care of the distribution 
problem.

The rest though is normal new version management.  Yes, it's a pain, but it's a 
pain whenever you have a 
distributed computing environment.  How do you currently manage new versions of 
PC software?  Client Access 
and its ilk?  Word processors?  New version of OS? etc, etc, ad infinitum.

Java on the AS/400 must be client server (excpet for a few stand-alone host 
programs but anything involving 
user interaction needs a GUI and that means a client).  So you can put all the 
database work in host Java 
(applications or servlets) at the server (where it belongs) and use the PC for 
display/user interaction 
(that's all they are good for anyway -- oh, and games) and minimise changes to 
the GUI through adequate 
model/view/controller separation and simply not changing the GUI until you have 
to.

Java is changing rapidly and the names of classes and packages sometimes change 
too (nasty, that!) although 
that is generally kept to a version boundary.  In that case you decide when the 
new features outweigh the pain 
of incorporating them.  Note that adequate abstraction will assist by hiding 
implementation dependencies like 
package names and class names.  Remember that Java is unlikely to receive the 
sort of long support periods we 
have been used to with the AS/400.  You will be required to keep reasonably 
current with your JDK or runtime.  
However, it will slow down as the designers get Java the way they and users 
want it.

Regards,
Simon Coulter.

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