Fwd: Interesting Observation

for the record.

---------- Forwarded message ----------
From: Geoff Longman <[email protected]>
Date: Feb 19, 2006 3:13 PM
Subject: Interesting Observation
To: Tapestry development <[email protected]>


Did you know that the namespaces for Framework and Contrib overlap?

I'm writing some code to detect when namespaces (based on the location
of the spec file) overlap and as a lark I added a test case that
checks if Framework and Contrib clash. They do.

Of course Framework is "special" and you couldn't exploit the overlap like this:

@framework:contrib/components/Choose

and Contrib.library is a package below Framework. You can't refer to a
framework component from contrib unless this was legal:

@contrib:../form/Button [General Q] illegal in classpath? - what about
in the context?

So I guess it's no big deal. But an interesting example of the
boundary crossing stuff I've been blathering about lately.

Note though that user libraries do not have the special status of
Framework and thus no protection from strange behaviour based on name
choice.

ahh, but the following are both legal even though the inspector
library is 'private' to Contrib.

@contrib:inspector/DumpObject
@contrib:DumpObject

In that case no immedaite ill effects would be observed as both
libraries refer to the same .jwc file and the meta's for
'org.apache.tapestry.component-class-packages' are the same in both
Contrib.libary and Inspector.library. ie:

  <meta key="org.apache.tapestry.component-class-packages"
value="org.apache.tapestry.contrib.components"/>

I think this is a very unusual case though as I've not seen two
libraries declare the same component this way.

These are also legal and serve only to expose components/pages  in
Inspector that are not for public use:

@contrib:inspector/ShowProperties
@contrib:inspector/ShowDescription
@contrib:inspector/ShowEngine

<span jwcid="@PageLink" page="contrib:inspector/Inspector"/>

etc.

Geoff

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--
The Spindle guy.          http://spindle.sf.net
Get help with Spindle:   
http://lists.sourceforge.net/mailman/listinfo/spindle-user
Blog:                     http://jroller.com/page/glongman
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