[jdom-interest] [Fwd: JDOM ?]
dms at sosnoski.com
Mon Mar 11 18:07:49 PST 2002
You can subclass SAXBuilder and override the createParser method to only
create a parser the first time through. That's probably the simplest
solution to get reusability (though I haven't looked into whether there
might be other issues).
It seems like this is a reasonable thing for SAXBuilder to do by
default, though. Is there any reason you'd want the code to always build
a new parser? I can't think of any.
Jason Hunter wrote:
>Please include Kim on any replies.
> JDOM ?
> "K.Gillies" <kgillies at gemini.edu>
> Mon, 11 Mar 2002 16:28:14 -0700
> jhunter at acm.org
> Hi Jason,
> I apologize for writing you directly. I'm not a regular watcher of
> the JDOM
> lists although I'm use JDOM -- and I like it! So if you like, please
> give me
> I have an application that reads many XML files that must be
> validated to
> several DTDs. Someone suggested that creating XML parsers and
> every time a new file must be parsed was rather expensive and that
> should be cached like JDBC connections are often cached. A new parser
> isn't needed for every document. I didn't do any measurements since
> it seemed like a reasonable statement.
> So I built a class to provide a central cache of SAXBuilders (one to
> start with) and allowed clients of the cache to add EntityResolver
> to locally return entities. My single EntityResolver just goes through
> all the client EntityResolvers one by one.
> All was good until I tried parsing multiple documents, then I got a
> JDOMException "Error in building: Stream closed"
> I then went to the SAXBuilder source to look around. What I found
> is that
> SAXBuilder always creates a new parser in the build method. So all my
> were misplaced. It appears that SAXBuilder can't be resued.
> Do you have any comments on this? Shouldn't I be concerned about
> the cost of
> creating/configuring parsers every time a new document must be
> parsed? One
> case where this seems important is a web service that needs to handle XML
> messages (like a service using SOAP).
> Is there a way to reuse a SAXBuilder and not create a new parser for
> Thanks for any advice you have.
> Kim Gillies
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