From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 109fba,7f8fc37d854731d6 X-Google-Attributes: gid109fba,public X-Google-Thread: 114809,7f8fc37d854731d6 X-Google-Attributes: gid114809,public X-Google-Thread: 1108a1,7f8fc37d854731d6 X-Google-Attributes: gid1108a1,public X-Google-Thread: 103376,7f8fc37d854731d6 X-Google-Attributes: gid103376,public From: piercarl@sabi.demon.co.uk (Piercarlo Grandi) Subject: Re: Interesting but sensitive topic to discuss (HELP: - OOP and CASE tools) Date: 1996/11/27 Message-ID: #1/1 X-Deja-AN: 200950496 x-nntp-posting-host: sabi.demon.co.uk x-disclaimer: Contents reflect my personal views only references: <32813322.41C6@kyebek3.kjist.ac.kr> <55pqr5$136a@grimsel.zurich.ibm.com> <328109CD.6685@concentric.net> content-type: text/plain; charset=US-ASCII mime-version: 1.0 (generated by tm-edit 7.94) newsgroups: comp.object,comp.lang.c++,comp.lang.ada,comp.lang.smalltalk Date: 1996-11-27T00:00:00+00:00 List-Id: >>> "menio" == Anthony Menio writes: menio> On 18 Nov 1996, Piercarlo Grandi wrote: >>>>>> "menio" == Anthony Menio 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)?