Re: OO Design induces an existential crisis


"AndyW" <foo_@xxxxxxxxxxxxxxxx> wrote in message
news:kmree1t4emdsqbin8pv9bmfr86ouo7cddv@xxxxxxxxxx
>
> You have described an abstraction by calling it a container not an
> object. The purpose of the discussion is to be able to tell the
> difference and once thus knowing the difference being able to modle
> them using different techniques.
>
The object you were describing is a container. Containers are one
of the most common objects in OOP. It is not improper to ask what
kind of object is it.

Each object has changeable attributes and non-changeable attributes.
The color of the container is probably non-changeable. If so, we
don't need methods related to color. The handle does not change.
Therefore we don't need methods for the handle. The state of
the container does change. It either contains something or it does
not. We need methods to reflect that.

Software is about change. If nothing changes, there is usually no
point in creating a software object. OOP is about encapsulating
that change and providing an interface (public methods) to effect
and inspect those changes. If nothing changes, we don't need
methods. Does the handle change? Probably not.

Failure to understand the importance of change, how to reflect
change, and how to design for change, is a fundamental problem
for novices in object technology. It seems this is also a frequent
problem for those who have a long experience with object
technology.

Once this is understood, there is no existential crisis.

Richard Riehle


.

Relevant Pages

  • Re: OO Design induces an existential crisis
    ... First, Andy, I do not have a fixation on containers. ... We have many categories of classes in object technology. ... One of those categories is the container class. ... We can create instances of class Stack. ...
    (comp.object)
  • Re: OO Design induces an existential crisis
    ... >The object you were describing is a container. ... A container is not an object, its an abstraction. ... >change, and how to design for change, is a fundamental problem ... >for novices in object technology. ...
    (comp.object)