OO design

["David Baelde" <david.baelde@gmail.com>]

Hi,

I'm no OO guru, so my question may be irrelevant, or there just might
not be an answer, which wouldn't hurt..

Let's say that I have a base class, with some kind of activation
procedure: anybody wanting to use the class must call #enter before,
and then call #leave for releasing. Internally, the methods #do_enter
and #do_leave are called respectively at the first #enter and last
#leave.

Nobody should call the #do_* directly, and I'd also like to make sure
the #enter and #leave are never overriden, since their behaviour is
important and actually much more complex than what I said.

I could just rely on the user who derives my base class, but let's see
what we can do. First the #do_* should be made private, so they can be
defined in the derived classes, but never called from the outside. To
avoid the overriding of #enter and #leave the only solution seems to
make them normal functions instead of methods. But then how could
#enter call #do_enter ? I tried to first define the class with public
#enter and make that method private in the interface, but OCaml told
me that was impossible.

I'm just curious if anybody has an opinion/idea about that.
--
David