Very good stuff, Dmitri!
I'm using your excellent JXPath library in my jpath.xsl XSP
logicsheet, in conjunction with the continuations-based control flow
layer.
I've got a small suggestion for an optimization, if you don't mind. In
the implementation I have, 0.1-dev from Jakarta's CVS, I noticed
there's no way to compile an XPath, before using it. Having a way to
compile the XPaths to be used later, would considerably improve the
performance in repeated operations.
E.g. right now you have something like this:
Object bean = ...;
JPathContext context = JPathContext.newContext(bean);
context.getValue("some XPath");
I'd like to also have the ability to do:
Object bean = ...;
JPathContext context = JPathContext.newContext(bean);
XPathObject xpath = new XPathObject("some XPath");
context.getValue(xpath);
With this approach, I can setup a dictionary of already compiled XPath
expressions, and use compiled XPaths, instead of having Xalan
interpret the XPath all the time.
Last time I checked, Xalan did have the ability to precompile XPaths
in its internal format, so maybe this is easy to achieve.
Best regards,
--
Ovidiu Predescu <[EMAIL PROTECTED]>
http://www.geocities.com/SiliconValley/Monitor/7464/ (GNU, Emacs, other stuff)
On Wed, 10 Apr 2002 21:18:47 -0500, "Ivelin Ivanov" <[EMAIL PROTECTED]> wrote:
>
> "Ask and you shall receive"
>
> Dmitri makes us another great present with the new JXPath.
> Some of the features are just what I needed to make form handling more
> transparent.
>
> Enjoy,
>
> Ivelin
>
>
> ----- Original Message -----
> From: "Dmitri Plotnikov" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Wednesday, April 10, 2002 8:06 AM
> Subject: [jxpath] New features, bug fixes and documentation
>
>
> > In preparation for its first release, JXPath is undergoing some clean-up.
> >
> > There is now documentation: a tutorial, which is included with the binary
> > distribution. It is in the CVS repository, but not yet accessible via the
> > Jakarta website - read it at
> >
> > http://www.plotnix.com/jxpath/docs/users-guide.html
> >
> >
> > I have committed several bug fixes and added some new features.
> >
> > JXPath can now create objects! You just provide an implementation of the
> > AbstractFactory interface and call createPath(path, value) on
> JXPathContext.
> > It will behave the same way as setValue, except it will call the factory
> as
> > needed. An interesting idea would be to write one of those factories that
> > would take Struts mapping configuration and create form beans as needed.
> >
> > Support for diversity object models is now complete with the introduction
> of
> > NodePointerFactory. We can now have modules that support DynaBeans, JDOM
> > etc. In fact, I plan to write some of them in the near future. JDOM
> sounds
> > like the most interesting alternative to DOM to work with.
> >
> > There is a minor type conversion change: JXPath will now cast a
> > single-element array or collection to its first element. This feature can
> > be used for instance with HttpRequest parameters. How do you know if a
> > parameter is a singular or a collection? Now you don't need to - extract
> it
> > as a collection, give the collection to JXPath, it will convert the type
> if
> > needed.
> >
> > There are two incompatible changes, both having to do with extension
> > functions. First of all, the API of Function changed (there is now an
> > additional argument, ExpressionContext). Second, the behavior of
> > ExpressionContext has changed. It now behaves properly. I hope these
> > changes don't break anybody's builds. If they do, I apologize in advance.
> >
> > One of the fixes improves an optimization, which up until now was just
> > there, not actually optimizing anything.
> >
> > Behavior of getContextNodePointer has been fixed - it used to be
> destructive
> > in some cases.
> >
> > There are many other minor fixes.
> >
> > JXPath is getting ready for its first official release!
> >
> >
> > - Dmitri Plotnikov
> > PLOTNIX, Inc
> >
> >
> >
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