Re: Got the Issue

[Soumya Chatterjee]

The issue I think is not that it fails multi threading environment in NodeList because the way it does the caching. 
 
If no one is changing any value of the DOM object and only reads from it then setting the following should work in NodeList implementation. 
docBuilderFactory.setAttribute(http://apache.org/xml/features/dom/defer-node-expansion, Boolean.FALSE)
 
But it does not work because the NullPointerException is noting to do with the multi threaded access but it is due to the way it does the caching. Now in the Node implementation when we use getFirstChild and getNextSibling, it is not doing any caching and resolved the issue. I still think that NodeList should not give a null pointer exception because that is not desirable in any enterprise architecture where multi threading and performance have no alternative.
 
Please let me know if I am wrong in my analysis.


Thanks,Soumya ChatterjeeTata Consultancy ServicesMailto: [EMAIL PROTECTED]Website: http://www.tcs.com____________________________________________Experience certainty. IT ServicesBusiness SolutionsOutsourcing____________________________________________ 




Michael Glavassevich <[EMAIL PROTECTED]> 
07/26/2007 09:51 AST

To  
j-users@xerces.apache.org


cc  
Soumya Chatterjee <[EMAIL PROTECTED]>


bcc  



Subject  
Re: Got the Issue


Prashant Reddy <[EMAIL PROTECTED]> wrote on 07/26/2007 02:19:05 AM:> Like someone else suggested earlier have you tried turning off the> Defered node expansion to see if you still face any problems ?>>> Try :> docBuilderFactory.setAttribute("http://apache.> org/xml/features/dom/defer-node-expansion", Boolean.FALSE);>> Be adviced that turning this feature off will mean your code (even if it> works) will have a semantic-lock in to behavior of Xerces XML parser.If you're relying on certain DOM operations being thread-safe you'vealready locked yourself in, perhaps to a specific version of Xerces. Yourcode may not work with other DOM implementations and there's no guaranteethat it will work with future releases of Xerces (even the next bug fixrelease).> > http://issues.apache.org/bugzilla/show_bug.cgi?id=27687>> I am not sure fixing the parser to become thread-safe when it is already> declared to be not a goal is such a good idea. Besides there may be> other places in the xerces code where assumption of no concurrent access> may be made.Indeed there are. At the risk of encouraging folks to write more brittlecode I won't list them here.> -PrashantThanks.Michael GlavassevichXML Parser DevelopmentIBM Toronto LabE-mail: [EMAIL PROTECTED]E-mail: [EMAIL PROTECTED]ForwardSourceID:NT00020E1A =====-----=====-----=====
Notice: The information contained in this e-mail
message and/or attachments to it may contain 
confidential or privileged information. If you are 
not the intended recipient, any dissemination, use, 
review, distribution, printing or copying of the 
information contained in this e-mail message 
and/or attachments to it are strictly prohibited. If 
you have received this communication in error, 
please notify us by reply e-mail or telephone and 
immediately and permanently delete the message 
and any attachments. Thank you