Serialising vs modelling

[David Berry]

Doug,

> For example, for SSA we are defining the SSA data model including a
> reference (abstract) XML serialization and schema.  Both of these are
> part of the SSA data model.  The SSA protocol specifies an access protocol
> based on the SSA data model.  The SSA protocol defines a query interface,
> a query response, and standard representations of the SSA data model
> in VOTable, FITS, XML, and text.  The XML version will be closest to
> the serialization defined by the data model, but may include additional
> elements defined by the service.

Sound's like you've got the data model sorted!

> A key point is that all such data representations implement the same data
> model.  Class code would implement the abstract data model, independent of
> any specific representation (including XML).  The transport layer deals with
> encoding and decoding the data model in various external representations.

Yes indeed. The interface defines the model, not a specific XML
serialisation. Once we have a model interface, code can be written which
uses it, and then "plugins" can be written to read and write objects in
a range of specific serialisations. I guess this is how things like Paint
Shop Pro handle different photo formats.

David


David


----------------------------------------------------------------------
Dr David S. Berry    (dsb at ast.man.ac.uk)

STARLINK project		 |	Centre for Astrophysics
(http://www.starlink.ac.uk/)	 |	University of Central Lancashire
Rutherford Appleton Laboratory	 |	PRESTON
DIDCOT				 |	United Kingdom
United Kingdom			 |	PR1 2HE
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