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Re: deadlocks

On Sat, 20 Nov 1999, Zvi Avraham wrote:
> >%_
> 
> Falko Braeutigam wrote:
> 
> > On Fri, 19 Nov 1999, Zvi Avraham wrote:
> > > Hi,
> > >
> > > I retested my Cocoon OzoneProducer with Ozone 0.3.2.
> > > The problem now that when I accessing already stored documnet not by
> > > DOMConverter,
> > > Ozone client entres to deadlock ...
> > >
> > > So all this examples of printing XML document using OpenXML, XSL:P printers just
> > > stuck and nothing going on ...
> >
> > You can produce deadlocks with just one client connection????
> 
> maybe this is not "deadlock" as I studied it in OS course :)
> when I connecting to Ozone server, from other clients (Load.java with DOMConverter -
> it's ok), but when I connecting from Cocoon or just Load.java modified to print
> document using OpenXML or XSL:P printer - it's just stuck , but other clients still
> work.
> 
> > The problem of ozone and cocoon is that coccon assumes that the DOM is an
> > in-memory DOM - its entire architecture is based on this idea. So it is not
> > possible for the OzoneProducer to just retrieve the DOM from ozone and give it
> > to cocoon because cocoon will probable change the DOM tree before it will
> > finally change ot to HTML and give it to the client. When using the DOM
> > retrieved from the ozone DB this will change the db content too! And this is
> > probably not what you want. Zvi, how did you address this problem?
> 
> I know this - 
...and I know that you know this ;) I just wanted to describe some ideas
behind cocoon to list members that are not that familiar with cocoon.

> Cocoon removing PIs from the document sometimes,
> but I was successfully working with IPSI PDOM from Cocoon.
> Cocoon 2 will address this issues, so source document will not be modified
> (it will use SiteMap, instead of PIs).
What about DCP? With DCP I can add as many nodes to the DOM as I like. Using
ozone DOM this would change the database!

> 
> BTW: this reproducing without Cocoon too, just try to print document using OpenXML or
> XSL:P printer ...
> 
> > Can you send us the code of your OzoneProducer? We may better find the problem this
> > way. You know cocoon, we know ozone - maybe it's a good idea to work together on the
> >
> > OzoneProducer.
> 
> Sure, Ann, sent me source code of her Cocoon OzoneProducer, but b/c it's her first
> experience with servlets - I completely rewrote it :-)
> There are still many things to implement:
> 1. Configurable interface - so user will be able to put database username, password,
> host and port into Cocoon config file
> 2. XPath query support
> 3. XSLT processor support
> it's not big deal, but I still unable to get basic PDOMt to work with Ozone :)
> 
> I attaching OzoneProducer source to this email, you can put there whatever license you
> want :), after this will work you can put it to ozone XML samples directory ...

Thank you Zvi and Ann. I made a new "Cocoon" sample. Hopefully the OzoneProducer
will evolve overtime to become a to a real usefull tool to use ozone as data
source of cocoon.

First of all, we will try to get the OzoneProducer to work ;)


Falko
-- 
______________________________________________________________________
Falko Braeutigam                         mailto:falko@softwarebuero.de
softwarebuero m&b (SMB)                    http://www.softwarebuero.de