In the last mail I sent (was Re: more integration) I promised to
send an email to Ralph Johson asking him for the meaning of the
term dynamic interface of an object in the following paragraph
of a paper by him on application frameworks:

----- by R. Johnson ----

Current PLs are good at describing the static interface of an object,
it is hard for developpers to learn the collaborative patterns of ah PL's,
framework by reading it.
Instead, they depend on other documentation and talking to experts. Patterns
are one approach to improving the documentation. Another approach is to
describe the constraints and interactions between components formally, such
as with contracts [Holland et al.].
But since part of the strength of frameworks is
the fact that the framework is expressed in code, it might be better to
improve OOPLs so that they can express patterns of collaboration more
clearly.

---- end of reference to Johnson --------

In the following is his answer on this subject.                               

> To: Mira Mezini <mira@ccs.neu.edu>
> From: johnson@cs.uiuc.edu (Ralph E. Johnson)
> Subject: Re: paper on application frameworks
>
> At 4:33 PM 1/22/98, Mira Mezini wrote:
> >I want to be sure about the meaning of "dynamic interface" in this
> >paragraph. My understanding is:
> >
> >        static interface == the set of methods defined on an object
> >
> >        dynamic interface == collaborative patterns encoded in the
> >                             behavior of an object, i.e. the set of
> >                             paths through which responsibilities
> >                             flow during run-time  -
>                               in other words the protocol
> >
> >Is my understaning of the terms you use right?
>
> Yes, that is a good explanation.
>
> -Ralph