[Grok-dev] Simple adapter question
optilude+lists at gmail.com
Thu Mar 5 23:03:52 EST 2009
Jan Ulrich Hasecke wrote:
> So why the class Home is defined at all?
Home is the actual adapter (or, more precisely, the adapter *factory*:
the thing that Zope calls to get back an instance of the adapter
(calling a class object gives you an instance object)). It needs to be
I think the reason why this is confusing is that the adapter is the
defined in the same code listing as the user of the adapter. The point
of using an adapter is normally that you have multiple possible contexts
coming from different sources, spread over your code base. You adapt
those to an interface you know how to deal with, in order to make your
code more re-usable.
Also, the example isn't terribly realistic, and even then,
multi-adapters are most commonly used as an implementation detail behind
browser views (which multi-adapter a context object and the request).
I've used them in code I've written, but usually only in "framework"
If you have my book, you may find parts of chapter 9 useful reading on
this topic as well.
Author of `Professional Plone Development`, a book for developers who
want to work with Plone. See http://martinaspeli.net/plone-book
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