Re: Interesting but sensitive topic to discuss (HELP: - OOP and CASE tools)

[piercarl@sabi.demon.co.uk (Piercarlo Grandi)]

>>> "menio" == Anthony Menio <menio@earhart.montclair.edu> writes:

menio> On 18 Nov 1996, Piercarlo Grandi wrote:
>>>>>> "menio" == Anthony Menio <menio@pegasus.montclair.edu> writes:

menio> On 11 Nov 1996 > 

piercarl> Do OO programs by and large describe static relationships
piercarl> between modules (or parts thereof like interfaces)? Or do they
piercarl> describe collections of instances/clones of those modules (or
piercarl> their types) and how they interact?

menio> I think the answer to this can be found in the analysis model.
menio> The analysis model descibes the objects that will be existance
menio> during the systems existance. In this model and thus the
menio> functioning system your interested in definate articals ie actual
menio> entities not classes of entities(ie currentProcess, ActiveWindow,
menio> nextTransaction, rather than definitions of the types which these
menio> are instances of) . The relationships expressed are dynamic ones
menio> as the effects of the messaging between these objects will be
menio> related to thier state.

piercarl> According to your argument, which has already been seen in
piercarl> slightly different guises, if a bank has a customer list
piercarl> application, then the analysis model will describe N million
piercarl> objects if the bank has N million customers. If the bank
piercarl> acquires a new customer, or loses a customer, then the
piercarl> analysis model will have to be revised, for the "objects that
piercarl> will be in existance during the system existance" will have
piercarl> changed.

menio> A system in which a 1:N object relationship exists

I am not familair with this concept: what is an 1:N object relationship?

A customer list application has N million customer objects, which can be
related among them in many ways; for example there might be a
"provided_reference" relationships between one object and many others,
or a "cosignatory" relationships between several customer objects (and
an account object, presumably).

menio> and often undergoes large changes in the n side of this
menio> relationship requires a structure capable of handling these
menio> changes. An analysis model which describes the system as dynamic
menio> interactions and relations between objects is fundamental in
menio> creating such a structure.

Why is it fundamental to model N million objects, as opposed to just
modeling their type/class/prototype?

menio> The example you mention can only be though of in terms of varying
menio> numbers of instances of a customer class, thus in terms of
menio> objects.

I frankly cannot think in those terms; I can only think of it in terms
of classes, for otherwise one has to keep track of all the individual
relationships among individual objects. That's sometthing computers are
good at; when I write a program i want to deal with abstractions, be
they classes or prototypes.

menio> The behavior being modeled is in terms of messages between some
menio> subset of the N customers and the list object.

Which list object? I haven't seen any mention of a list object. What I
have seen mentioned is a list of N million customers; this list may be
implemented as a list object, or anything else; then there may be M
million customer accounts, X million transactions between those
accounts, and so on.

menio> The very concept of sending messages to multiple copies of the
menio> same class

Which concept? Where has this concept arosen?

menio> by definition requires you to think in terms of objects.

Why? It seems to me that to model relationships between groups of
essentially similar entities one should well describe them abstractly in
terms of the types of those entities.

menio> Even in class definition your thinking is in terms of a typical
menio> instance of the class being created.

Really? Consider some sort of 'complex' class: what is a ``typical''
complex number?

menio> Implementation of behavior is defined in terms of state, state is
menio> a characteristic of objects.

Really? What is the state of the object representing the complex number
(2,3i)?