Re: [Vtd-xml-users] xerces discussion on VTD

[Jimmy Z. <cra...@co...>]

See my comments below

----- Original Message ----- 
From: "Tatu Saloranta" <cow...@ya...>
To: "Jimmy Zhang" <cra...@co...>; "Paul Tomsic" <pt...@gm...>; 
<vtd...@li...>
Sent: Wednesday, January 17, 2007 10:48 AM
Subject: Re: [Vtd-xml-users] xerces discussion on VTD


> --- Jimmy Zhang <cra...@co...> wrote:
>
>> Thanks. It would take sometime to take VTD
>> seriously...
>> Given that DOM and SAX are so bad for so long,
>> people
>> have literally got used to them... and sometime had
>> a tough
>> time getting out of the "cave."
>
> It is true, however, that VTD-XML as well as any other
> tools has its optimal use cases, and limits.
> I think it is useful to be clear about both benefits
> (compact representation, efficient just-in-time
> extraction if only parts of content are needed, fast
> serialization likewise if modifications are small) and
> limitations.
>
> There are really 2 major limitations I think:
>
> (a) It does not (and probably will not) handle DTDs:
> validation is not the problem (it could be
> implemented), but entities are, and perhaps things
> like attribute defaulting and normalization. This may
> be problematic for document-centric approaches, but
> usually is not for data-centric (like SOAP messages
> etc)

DTD seems to have been depleted somewhat, e.g.
in SOAP, various types of industry specific vocabularies,
RDFs... XPath and XQuery doesn't even have the notion
of DTD anymore...

> (b) Namespace handling is not very complete, nor
> efficient; this because the way namespaces work is
> somewhat conflicting with the way VTD-XML does its
> processing, to obtain high speed. So I am not sure if
> it should be used for documents with namespaces.
>

The name space handling is quite efficient... most cases
I have not seen much difference at all... as to the completion
part, I have two thoughts, one is that the namespace spec
itself has issues, the second is that adding complete support
of it should not be difficult nor inefficient...

> There are still many use cases where neither above is
> a problem: but there are also cases where it is.
> Clearly understanding limitations and benefits, and
> choosing right tools based on this is essential.
>

I don't know why some kept thinking VTD is compressed
DOM...does it look like compressed DOM to you?


> -+ Tatu +-
>
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