RE: Re: Object properties -- RPG400-L

Murali,

I'll try to take a stab at this....

OS400 is called "object oriented", which I'll agree with, to a point.  In
OS400, everything that exists on the machine is an object, and each object
type is only allowed  to do certain things.  Lets look a a few basic objects
in OS400

*PGM -- Program object.  OS400 recognises this object as an executable
object.  Only actions relating to programs can be performed with this
object, such as "Call".

*FILE -- Relational Database Table object.  Files on OS400 carry all sorts
of attributes such as record length, number of fields, field definitions,
ccsid information, access path maintenance info, and so on....  All files
will support the basic methods: read, write, update.  Special attributes may
allow for special commands to be used with the object.  Physical files and
display files both support the basic read/write methods, but their extended
attributes allow for persistent data storage in one object, workstation I/O
in the other.  You cannot use a PF file to do screen I/O, and you cannot use
a DSPF to store persistent data.

Now, consider an OS that does not understand objects.  In Dos, a file is a
stream of data, and nothing explicitely limits you from trying call a data
file (indeed, this is one way a virus can propagate).  The use of name
extensions to represent the object type is very weak and vulnerable to
misuse.

This is a very limited explanation, but I hope it helps.  I think the term
"object oriented" is a bit misleading, as we immediately think of "object
oriented programming" and all the little things like encapsulation,
inheritence, polymorphism, (and so forth), that make up an OOP language like
Java or Python.

-----Original Message-----
From: MURALI DHAR [mailto:nmuralidhar@rediffmail.com]
Sent: Monday, November 11, 2002 7:55 AM
To: rpg400-l@midrange.com
Subject: Re: Re: Object properties


Barton,
i wanna know situations where this object properties are
implemented..I hope u agree with me that AS400 is object oreinted
system...HOw do u justify where this object properties will come
into picture while using RPG,ILE procedures etc....I was asked
this question by Project Manager of one company when i went for
intw?
Kindly suggest me!
Murali

On Mon, 11 Nov 2002 Mike.Barton@pinkroccade.co.uk wrote :
>
>
>
> >Hi
> >I can you quote examples (some situations)for all the
>properties
> >of Object since AS400 is object oriented system....I would like
>to
>snip
> >encapsulation etc?
> >I hope Iam clear in my question to you...
> >Regards&Thanks,
> >Murali
>
>Murali
>      if you are refering to RPG (this is the RPG list) , it is
>not an OO programming language. There is no concept of
>a objects/methods etc  unlike Java and others.
>
>Mike
>
>
>
>
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