perfsonar development work

[Maciej Glowiak <>]

Hi Jochen

Jochen Reinwand wrote:
> Hello Maciej,
>
> On Thursday 05 April 2007 15:39, Maciej Glowiak wrote:
> > I have similar impression how the client API should look like.
>
> > From the examples you gave I can see that what you have in Java and also what 
> you're planning to do is really exactly what I had in mind ;-)
> I wonder what the problem was during the discussion in Utrecht...

Hmm, I think there were several discussions on that topic. One was 
Client API for LS. In general, people wanted:
1) definitely to have it
2) to have it quite generic (to be re-used in other services)
3) to have also API for other services - without discussing on what,
   when and how. That were more or less fuzzy discussions.

> > 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. So we need to 
convert twice to and from NMWG. We could get rid one of two:

a) NMWG classes and use just DOM Document
b) Axis and use HTTP+NMWG classes

We had quite long discussion on it but in fact we need both of them. 
Axis for security (we agreed not to remove Axis until we decide how to 
implement AA, perhaps using WS-Security). NMWG classes are useful for 
developing our services in Java. We don't care about all the syntax of 
NMWG, we just create objects.


> 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.

Maciej

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| Maciej Glowiak        Network Research and Development            ||
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