Hi,
JAXP is just a set of interfaces to isolate you from the parser
implementation class. We use JAXP and have switched from Xerces
to Crimson and back at runtime without restarting the server and
without any problems.
As to the performance of various parsers: you may find that what
matters more than the parser implementation is your approach,
e.g. SAX, DOM, XSLT, etc. Just a couple of days ago, Sun
published a performance comparison of various parsers (including
Crimson and Xerces. I don't remember if aelfred was included)
and various parsing approaches. Check it out on the java.sun.com
site (there's also a link from www.theserverside.com).
Good luck,
Yoav Shapira
John Wadkin wrote:
>
> Rick,
>
> Simple question, here comes the complex answer :)
>
> I'm a student who's working for my Uni for a year. I'm working on a small
> project to look at how best to implement a new Government recommendation -
> that all Higher Education institutions in the UK have some sort of Personal
> Development Planning (PDP) for students.
> The project is funded by the Higher Education Funding Council (HEFC -
> "f-ki"), so we don't have a lot of cash! Unlike America, education in the UK
> hasn't yet sold out to the big multinationals ("Coca Cola day"). This means
> that instead of using a proper server, I'm having to make do with a
> workstation - a Sun Ultra 10. I'm no expert on servers, loads, load
> balancing and all that, but I should imagine that performance will be a
> problem. In view of this, I'm keen to squeeze as much out of the "server" as
> I can. The person who actually wrote the servlet recommends using Aelfred
> because of it's speed, hence my asking about using a parser other than
> Xerces.
> Thanks to Charlie, I checked the bug database - didn't think it would be
> bug, and it isn't. The bug database mentioned postings on the list about XML
> parsers, which I've read. From what I can tell (it isn't too clear):
>
> 4.0.1 only works with xerces.jar in common/lib - no per-WebApp parser is
> permitted
> 4.0.4 will allow per-WebApp parsers so long as it implements something
> called JAXP - i.e. xerces
>
> Looks like the developers have been reading Microsoft's marketing strategy
> :) I might have it totally wrong - I don't fully understand all the stuff
> about parsers and classLoaders - nor should I!
>
> Thanks,
>
> John
>
>
> Quote for the week:
>
> The stupid neither forgive nor forget; the naive forgive and forget; the
> wise forgive but do not forget.
>
> Thomas Szasz, The Second Sin (1973)
>
> -----Original Message-----
> From: Rick K [mailto:[EMAIL PROTECTED]]
> Sent: 13 March 2002 06:09
> To: Tomcat Users List
> Subject: RE: Problems using own XML parser
>
> Maybe you covered this before, but:
> Why doesn't Xerces meet your needs?
>
> I'm not much of an XML expert, I'm just curious.
>
> --- John Wadkin <[EMAIL PROTECTED]> wrote:
> > Charlie,
> >
> > It seems from:
> >
> >
> http://nagoya.apache.org/bugzilla/show_bug.cgi?id=6374
> >
> >
> http://nagoya.apache.org/bugzilla/show_bug.cgi?id=6628
> >
> > That webApps *can't* have their own parser. Stuck
> > with Xerces 1, then! Taken
> > a week to find that out :)
> >
> > Thanks,
> >
> > John
> >
> > Quote for the week:
> >
> > The stupid neither forgive nor forget; the naive
> > forgive and forget; the
> > wise forgive but do not forget.
> >
> > Thomas Szasz, The Second Sin (1973)
> >
> >
> > -----Original Message-----
> > From: Cox, Charlie [mailto:[EMAIL PROTECTED]]
> > Sent: 12 March 2002 16:27
> > To: 'Tomcat Users List'
> > Subject: RE: Problems using own XML parser
> >
> >
> > see the archives or bugzilla as this was addressed
> > in 4.0.3 or 4.0.4b1(I
> > don't remember which one)
> >
> > Charlie
> >
> > > -----Original Message-----
> > > From: John Wadkin [mailto:[EMAIL PROTECTED]]
> > > Sent: Tuesday, March 12, 2002 10:59 AM
> > > To: 'Tomcat Users List'
> > > Subject: RE: Problems using own XML parser
> > >
> > >
> > > I'm not privy to the workings of the servlet.
> > There's a
> > > properties file I
> > > edit to indicate the name of the SAX driver:
> > >
> > > #Xerces
> > >
> > sax.driver.name=org.apache.xerces.parsers.SAXParser
> > >
> > > OR
> > >
> > > #Aelfred
> > > sax.driver.name=com.microstar.xml.SAXDriver
> > >
> > > Xerces works fine, but Aelfred doesn't. The driver
> > names are
> > > correct and as
> > > I said, TomCat does load aelfred.jar
> > >
> > > Yes - I too would like to know if it's possible to
> > use another parser!
> > >
> > > Thanks,
> > >
> > > John
> > >
> > > Quote for the week:
> > >
> > > The stupid neither forgive nor forget; the naive
> > forgive and
> > > forget; the
> > > wise forgive but do not forget.
> > >
> > > Thomas Szasz, The Second Sin (1973)
> > >
> > >
> > > -----Original Message-----
> > > From: Evguenia Krylova
> > [mailto:[EMAIL PROTECTED]]
> > > Sent: 12 March 2002 15:52
> > > To: Tomcat Users List
> > > Subject: RE: Problems using own XML parser
> > >
> > >
> > > Isn't it that udner Tomcat 4x you can specify
> > class path for a
> > > context in server.xml. I saw something like this
> > in the
> > > comments portion of server.xml. I have not tried
> > this, but would
> > > like to know if you found a way to use another
> > parser with Tomcat.
> > >
> > > I assume you don't use JAXP API's but call
> > alphred's classes
> > > directly.
> > >
> > > Ev
> > >
> > > -----Original Message-----
> > > From: John Wadkin [mailto:[EMAIL PROTECTED]]
> > > Sent: Tuesday, March 12, 2002 9:31 AM
> > > To: Tomcat Users List (E-mail)
> > > Subject: RE: Problems using own XML parser
> > >
> > >
> > > All,
> > >
> > > I'd appreciate a response on this otherwise I'll
> > just have to
> > > assume that
> > > TomCat allows only xerces.jar as a parser.
> > > The "jsp errors" I mention relate to the default
> > servlet for
> > > jsp. I tried
> > > commenting out (in conf/web.xml) all references to
> > this
> > > servlet - it just
> > > created more errors!
> > > The docs give the impression that it's a "simple"
> > case of
> > > moving xerces.jar
> > > and putting your own parser in /WEB-INF/lib, but
> > this just
> > > doesn't work.
> > >
> > > Thanks,
> > >
> > > John
> > >
> > >
> > > -----Original Message-----
> > > From: John Wadkin
> > > Sent: 09 March 2002 03:04
> > > To: Tomcat Users List (E-mail)
> > > Subject: Problems using own XML parser
> > >
> > >
> > > All,
> > >
> > > Tomcat 4.0.1
> > > Apache 1.3
> > > mod_WebApp
> > > Solaris 8
> > >
> > > I'm trying to use the aelfred parser in a servlet.
> > I've read
> > > the docs on
> > > class loaders and XML but no luck so far.
> > >
> > > I moved xerces.jar from common/lib to server/lib
> > and
> > > re-started TomCat. A
> > > couple of errors appeared in catalina.out relating
> > to the
> > > default servlet
> > > for jsp's. So I put xerces.jar back in common/lib.
> > > I put the aelfred.jar in my web app's WEB-INF/lib
> > directory
> > > and re-started
> > > TomCat. I expected errors relating to the fact
> > that two XML
> > > parsers existed
> > > - there weren't any. The logs show that
> > aelfred.jar has loaded but the
> > > servlet throws a ClassNotFoundException.
> > >
> > > Any ideas? The servlet does work with Aelfred at
> > another site
> > > and it works
> > > fine with the xerces parser in common/lib.
> > >
> > > The reason I'm trying to use Aelfred is that I'm
> > told it's faster than
> > > Xerces. Is this a fair comment?
> > >
> > > Thanks,
> > >
> > > John
>
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