[AccessD] Framework Discussion - Implements

Ryan,

I can't help you with Implements because, in the stuff that I have been
doing, I can't find a use for it.  It seems to be a method of declaring that
a specific object belongs to a higher level class of objects, ad allow you
to dimension that object as that higher level object.

In other words, you define a class with PUBLIC variables (generally
considered a no-no) and a bunch of method and property STUBS.  Once you have
done that you create other classes that "implements" the parent class.  It
appears that the parent class' public variables magically become private in
the class that implements the parent object.  So from that perspective it
would be useful (If I could figure out how to do it) as a means of defining
a set of variables so that I don't have to define them again in other
similar objects.

The methods in the "parent" class have no code in them.  They are just an
empty declaration with a name and the parameters (with their type) that you
expect to be using in this parent object.  So... AFAICT you have managed
true inheritance for a small set of variables and defined that you will
provide a small set of methods.

I am quite sure that this is useful to some people.  It seems that the
argument is that you now can dimension your object as an instance of the
parent object and have early binding, able to see all of the properties
defined in that parent object etc.  What isn't clear (since I haven't ever
used them) is that whether I can also see all of my own custom properties
not defined in the parent object using early binding.  If so then using this
stuff would at least have a use to me.

OOP and what is called "implementation inheritance" means that you take a
parent class and "inherit" all of the code and variables in that parent.  If
the parent is a dog, and that parent class has a bark method, I can inherit
dog and not write a line of code have a barking dog.  I can now add "dance"
and I now have a dancing barking dog, but all I had to do is write the dance
method.  I have inherited the whole kit and caboodle including the
implementation of existing code in the parent.

Remember that Access' version has no code at all in that parent object
because it can't be inherited by the child object.

There are others on the list that actually use this stuff, at least out in
VB.  It would be nice if they could write a demo (in Access) that shows us
how this stuff all works, but no one has ever offered to do that.  I don't
know how so I can't do it for you.

8-(

John W. Colby
www.ColbyConsulting.com

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com]On Behalf Of
rsmethurst at uk.ey.com
Sent: Tuesday, March 16, 2004 11:06 AM
To: Access Developers discussion and problem solving
Subject: RE: [AccessD] Framework Discussion - Implements


Hi All,

In light of all the mails about classes, frameworks and implementation
etc. (most of which I am finding very interesting).

Could someone explain to me the difference between the  'Implements'
statement and how this is differs from inheritance.

Thanks
Ryan



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