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From Snehal Khanna <snehal_hari...@yahoo.com>
Subject Re: JXPath Performance
Date Fri, 06 Feb 2004 21:54:53 GMT
Thank you for this bit of input. My group had run
tests using XPathAPI and the numbers were quite bad
compared to JXPath. That is why I was curious to know
what you would gain by integrating with Xalan. I had a
hunch that CachedXPathAPI would probably what you had
in mind. 

However it seems that CachedXPathAPI is good so long
as the source document does not change. To compile
XPath expressions to use over any document, one would
need to use some other low level APIs.

Regards
Snehal

--- Dmitri Plotnikov <dmitri@apache.org> wrote:
> It is a little bit like comparing apples and
> oranges:
> 
> Xalan is an incredible XSLT processor. Its
> implementation of XPath is
> really, really fast (just don't use XPathAPI, use
> CachedXPathAPI instead).
> 
> JXPath is a highly flexible interpreter that applies
> the XPath syntax to
> mixed data models: it is not designed to be the
> fastest on DOM structures.
> Rather, it is optimized for general object graph
> traversal.
> 
> To summarize: if you need a high-performance XPath
> processor for DOM, go
> with Xalan.  If you need to traverse heterogeneous
> object graphs, go with
> JXPath. 'Simple as that.
> 
> I hope this helps.
> 
> - Dmitri
> 
> ----- Original Message ----- 
> From: "Snehal Khanna" <snehal_haridas@yahoo.com>
> To: "Jakarta Commons Users List"
> <commons-user@jakarta.apache.org>;
> <dmitri@apache.org>
> Sent: Friday, February 06, 2004 4:24 PM
> Subject: Re: JXPath Performance
> 
> 
> > Hi Dmitri,
> >
> > Have you done any tests comparing the performance
> of
> > JXPath to Xalan? It is imperative in my project to
> use
> > a really fast XPath engine so, it would be good to
> > know how much gain in performance we are talking
> about
> > here - especially for the case I mentioned
> earlier.
> >
> > Regards,
> > ~Snehal
> >
> >
> > --- Dmitri Plotnikov <dmitri@apache.org> wrote:
> > > JXPath is designed to work with heterogeneous
> > > models, including
> > > JavaBeans, Maps, Collections etc, as well as
> DOM,
> > > JDOM, etc.  To
> > > accomodate all this variety, JXPath inevitable
> > > produces some overhead.
> > > For example it creates a bunch of NodePointer
> > > objects during the
> > > evaluation of an XPath.  You wouldn't need such
> > > objects if you only
> > > worked with XML (DOM, JDOM).  Thus, JXPath is
> slower
> > > than for instance
> > > Xalan, which manages to allocate almost zero
> > > objects.
> > >
> > > I am currently working on some behind-the-scenes
> > > integration between
> > > JXPath and Xalan.  Once that's complete, JXPath
> > > performance will be
> > > similar to that of Xalan, as long as you are
> working
> > > exclusively with
> > > XML.
> > >
> > > I hope this helps.
> > >
> > > - Dmitri
> > >
> > >
> > > --- Snehal Khanna <snehal_haridas@yahoo.com>
> wrote:
> > > > We are in the process of evaluating two
> > > > implementations of XPath namely JXPath and
> > > jd.xpath
> > > > from www.aztecrider.com
> > > >
> > > > In our evaluations we have noticed that for
> XPath
> > > > expressions resulting in a node set with 100
> > > nodes,
> > > > the performance of jd.xpath is superior to the
> > > > performance of JXPath. It looks like JXpath
> loses
> > > out
> > > > on performance while iterating through the
> > > results.
> > > >
> > > > For XPath expressions resulting in a single
> node
> > > > output, the performance is comparable if we
> use
> > > > compiled expressions.
> > > >
> > > > Has anyone else performed a similar analysis?
> Are
> > > > there any known performance issues with JXPath
> > > that
> > > > are currently being addressed? In general what
> is
> > > the
> > > > development plan for JXPath in terms of
> > > performance
> > > > improvements and enhancements?
> > > >
> > > > Regards,
> > > > Snehal
> > > >
> > > >
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> >
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