“In his previous column, George Lebl talked about handling
multiple application documents using GnomeMDI. In this and the next
few columns, he will discuss Bonobo and other related
component-model technologies. This series begins with an
introduction to some Bonobo basics like the C API for CORBA.”
“In starting to talk about Bonobo, I’d like to recycle the
concept of a component model from my previous column. Component
models focus a user’s attention on documents rather than on
applications. But what exactly are components? Well, a component is
an object, much like a GTK+ widget or the Java string object, with
one important difference. Rather than being a single
implementation, a component is a piece of software separate from
the application. The component supports a set of well-defined
interfaces (but different components can implement the same
interface). So if an application knows how to embed components
(generally) with an embedding interface, it will be able to embed
any particular component that implements this embedding interface.
Then when someone writes a new program that handles new kinds of
documents, the application will be able to embed them without
requiring any changes to its code.”
“Components can also do things like display HTML text, in which
case the application uses the component only as a widget. This has
the advantage of making the application independent of any HTML
component installed on the user’s system, rather than having to
rely on a “hard-coded” component.”