RE: Porting Java applications from the 400 (was: SQL update/insert for astring contain " ' ")

Joe Pluta wrote:

>and, after some initial culture shock, they loved
>it.  Why?  For two reasons:

>1. You only write things once
>2. You only debug things once

I would add:

3.  What you write is a better match with underlying reality of the
business.

Procedural programming is focused, and over-focussed on "verbs."  Calculate
the payroll.  Write the check.  Indeed, put a few minuses in and you'll
probably find paragraphs with names like that in someone's COBOL code.

Object-orientation puts the nouns into programming in a meaningful way.  It
then attaches the verbs to the nouns.  This turns out to be much better
than having the verbs be "free-standing" as in procedural programming.

By doing this attachment, chaos is reduced because every check-writer in
the world doesn't have to know about every possible check in the world.
Behavior specific to payroll checks, as opposed to checks written by
purchasing, can be segregated easily and sensibly.  Behavior in common to
both can be readily shared with little or no performance penalty.  In the
procedural world, this stratification may or may not happen, because
nothing in the structure of the code itself ensures that it does.  And,
whether it happens or not, no maintenance advantage is achieved.  In O-O,
maintenance advantages accrue almost from day one, because its very
structure causes the advantage to occur.

Since we're plugging COMMON sessions, see my:

406173  Records That Talk: Why Java Matters

where I explain this in some detail, especially if someone doesn't
understand O-O to start with.





Larry W. Loen  -   Senior Linux, Java, and iSeries Performance Analyst
                          Dept HP4, Rochester MN