perfsonar development work

[Jochen Reinwand <>]

Hi Maciej,

On Tuesday 10 April 2007 14:59, Maciej Glowiak wrote:
> Jochen Reinwand wrote:
> > On Thursday 05 April 2007 15:39, Maciej Glowiak wrote:
> >> There are NMWG classes for Message construction and Axis functionality
> >> for SOAP. Unfortunately Axis uses DOM Document to store date, so our
> >> NMWG "DOM representation" must be converted into DOM Document. That's
> >> the performance issue to be resolved in the future.
> >
> > Yes, DOM can cause performance problems... Seems like the Perl
> > implementation of SOAP uses its own parsers. Perhaps they encountered
> > similar problems by just using some DOM module. But we are also using DOM
> > for our perfSONAR Perl implementation. So far the performance seems to be
> > acceptable. The DOM implementation we're using is more or less the Perl
> > interface to the standard Open Source C/C++ XML library libxml. This
> > library seems to be quite fast and C/C++ always tends to be faster than
> > Java ;-)
> >
> > But, anyway, seems like there is no "disagreement" on API design itself.
> > So we can most likely close this discussion.
>
> Yes, but the topic will be coming back... :)
>
> DOM itself is not a problem. The problem is with multiple conversions.
> Axis uses DOM Document. Our services use NMWG classes.

The NMWG classes are not using DOM? Our Perl implementation uses DOM. Somehow 
you can see it as an additional layer above DOM. This is very portable and by 
now fast enough for us.
If Axis provides access to the (internal) DOM structure, it might be useful 
to 
use these DOM structures within the NMWG classes... But, of course, you now a 
lot more about your code than I do ;-)

> > I'm still thinking about using the Java extension of Perl to directly use
> > the perfSONAR classes from within our Perl code...
>
> That could be interesting to investigate.

It's on my to do list for years now. Because of the Java reflection API and 
the very flexible Perl module system, it's very easy to use Java classes from 
within Perl. There are at least two implementations I'm aware of:
http://search.cpan.org/~metzzo/Java-4.7/Java.pm
http://search.cpan.org/~rusekd/Java-Import-0.03/lib/Java/Import.pm

It should be quite interesting to play around with these "mechanisms"...

Because of these easy mechanisms it might be a good idea to use the Java 
perfSONAR core functionality from within Perl. Compatibility between Java and 
Perl services would be very simple this way ;-)

greetings,
Jochen

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Jochen Reinwand                                 Tel: +49 9131 852-8689
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