Re: [xml-dev] XPackage: RDF/XLink-based packaging format

["Rick Jelliffe" <ricko@allette.com.au>]

From: "Garret Wilson" <garret@globalmentor.com>

> The OEB Publication Structure Working group values any comments you may have
> about our current XPackage draft, and we would welcome anyone who wants to
> participate more closely with the OEBF as we complete this specification.

XPackage looks like it would be a suitable and comprehensive packaging format to use 
in XAR (a mooted XML Application Archive format). 

I think DZIP[1] (my particular suggestion for XAR) addresses four areas that 
can distinguish itself from XPackage.

1)  XPackage is primarily concerned with packaging documents.

   XAR is not for sending documents bundled with metadata. It is for sending
   configuration, schema, templates and application files only, with no document, for the purpose
   of configuring generic XML applications. 

 2) XPackage does not specify any "physical bundling mechanism".

  DZIP specifies a particular physical bundling mechanism: ZIP/JAR.

 3) XPackage has a big buy-in, as far as its technology is concerned: parsing
   XML/RDF, linking with XLink, integrating to MIME etc., but is very flexible and 
   can handle things like fallback when resources are not required.

   DZIP has a low buy-in: just look in well-known directories of the 
   archive for files with well-known extensions.  A person who wants to
   create an XAR should only need to use WinZIP with no metadata
    required. There is no need to support internal versions or fallback.
   
  4) XPackage is aimed at describing the relationship between bits.
   
    DZIP is only interested in providing conventions for well-known
    roles.  Vendors/integrators may add arbitrary files whose
    purpose and format is only of interest to their particular tools;
    Jo Public does not need to know and the vendor does not need
    to explain. 

Given those very limited aims of XAR, XPackage is overkill and I think 
DZIP has clear advantages of straightforwardness and convenience.  

However, DZIP is not incompatible with XPackage. Any DZIP archive could
have an XPackage description document, just as it could have a RDDL
directory and SOCAT catalog.  In fact, an automated tool could be 
constructed to create the XPackage description document for any
particular DZIP archive.

Actually, I am assuming that DZIP is not incompatible with XPackage.
The RDF seems to let one say that "this is the XSLT stylesheet for that
XML document" but it is not clear to me how it can say "this is the XSLT
stylesheet for the future XML documents that use this XAR" 
Can I use XPackage for that? 

Cheers
Rick Jelliffe

[1] First draft at  http://www.topologi.com/public/dzip.html with pretty
similar aims to WAR web archives and JAR libraries.