Re: XML + Audit trails ?

Hi Nicolas-

Nicolas Ocquidant wrote:
Hello,

I have some general question about visAD.

Does visAD support XML format to store display informations ?
If no, is there a plan to make an XML adapter ?

Besides the work that Bill mentioned, Unidata is using XML
to store most information used in the Integrated Data Viewer
(IDV) that is built upon VisAD.  We store color tables used
by ColorControl, configuration info as well as persisting
the state of a VisAD display (e.g. map projection, display
projection matrix) in a "bundle" (xidv) file.  These xidv
files allow one to restore the state of the IDV from a
previously saved state.  It does not store the data, but
stores enough info to recreate the data from info in the
file.  Although we don't save all the data in an xidv file,
we do have the capability of persisting many VisAD objects
(Data, MathTypes, CoordinateSystems) in XML.  We do this
by saving off the information needed to recreated the
object.  Tags in the XML indicate whether data elements
are passed to constructors or (as in the case of ScalarTypes)
static methods used to create new objects.  So for a
RealType, we encode the name, default unit, default Set,
and attribute mask and when we decode the XML, the delegate
for RealType uses the RealType.getRealType method with
these elements. If there is no delegate for a particular
VisAD object, we resort to serializing the object and
storing that in a CDATA block in the XML (not the greatest
solution, but until we have delegates for all VisAD objects,
it works (mostly)).  The IDV source code is available at
http://my.unidata.ucar.edu/modules.php?name=Downloads)
and this is all done through the ucar.unidata.xml.*
and ucar.visad.VisADPersistence classes.  These could
be used independently from the IDV.

What about audit trails as it was mentioned in the "scientific data model
for interactive and distributed visualization" (www.csit.fsu.edu) ?
It wasn't released in 2000. And now ?

If you look at section 3.7 of the VisAD Programmer's Reference
(http://www.ssec.wisc.edu/~billh/guide.html#3.7) you'll see
that the AuditTrail class is mentioned, but not implemented.
It would be a nice addition if anyone in the development
community wants to tackle that.

Thanks a lot for your great job.

Don
*************************************************************
Don Murray                               UCAR Unidata Program
dmurray@xxxxxxxxxxxxxxxx                        P.O. Box 3000
(303) 497-8628                              Boulder, CO 80307
http://www.unidata.ucar.edu/staff/donm
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