[COMPONENTS] Gnome's OAF allows `Capability-based activation'...

Some of the previous emails talked about connecting components without
exactly knowing their interfaces. The OAF (Object Activation
Framework) within Gnome implements such a feature (and KParts in KDE,
if I am not mistaken):
``Oaf allows arbitrary fields and lists of fields to be associated
with a component via an XML description file. For instance, this
allows us to use a single command to "find an object that can handle a
certain MIME type, implement certain named interfaces, be edited and
render a certain version of HTML." this capability is exposed
via the SQL-like query language.''
(from
<http://www-106.ibm.com/developerworks/components/library/co-bnbo1.html>)
<http://developer.gnome.org/doc/API/liboaf/book1.html>

==========================

I also tried to come up with a description of "component" on the
glossary page <http://www.orocos.org/glossary.html>. Please comment on
this trial:

``A unit of composition with clearly specified interfaces and
functionality. It can depend on context, but this dependence is made
explicit. A software component is an independent unit, consisting of
different modules, should be reusable, exceeding the concept of
``small'' entities such as classes, be able to interrogate other
components to find their interfaces (and be interroated itself), be
able to generate and handle events, and deliverable by third parties
on the basis of its interface specification only.''

One of the important things is this "interrogateability", I think...

Herman

-- 
"I decry the current tendency to seek patents on algorithms. There are
 better ways to earn a living than to prevent other people from making
 use of one's contributions to computer science."  D.E. Knuth, TAoCP 3