On Jul 25, 2005, at 7:00 AM, Tim Ellison wrote:
Tom Tromey wrote:
"Tim" == Tim Ellison <[EMAIL PROTECTED]> writes:
Just some random thoughts on this.
Tim> The goal is to (a) stimulate discussion, and (b) think about the
Tim> components that we should declare with well-defined
interfaces to other
Tim> components (I'm thinking of OSGi bundles here).
In most cases I think places where one package needs another can be
implemented solely with the public API. However there do seem to be
a few cases where it is convenient to share across package
boundaries.
I don't think that a _package_ is the right level of componentization,
which is why I tried to group sets of packages into a single
component.
I agree that in most places the implementation of a component is
primarily though public APIs on other components. So, for example,
the
public APIs would be exported from the OSGi bundle, but the
implementation would remain mostly hidden.
I assume that what we really need is two kinds of component export,
the public app level API (java.util.*) and a public-yet-not-for-app-
but-fellow-traveler API, such as what other conspiring modules would
export to each other to provide the full public API.
Kinda like "friend API" w/o the horror of having to declare who your
friends are...
Some of this depends on exactly how you want to implement things.
E.g., in Classpath we implement java.io primitives in terms of
java.nio. You could do this differently of course, but maybe you'd
want to somehow share the native layer. (A similar example has to do
with charset conversion; in Classpath everything is done with nio,
but
libgcj for instance has its own approach *and* the nio code.)
Agreed, and if we are explicit about what a particular component
provides by its public API, and what it needs to import from others'
public API, we can mix and match implementations (i.e. versions)
robustly.
Sure - Can we also version the supported public-for-friend API in
some way? (I need to go read the OSGi spec...)
--
Geir Magnusson Jr +1-203-665-6437
[EMAIL PROTECTED]
