Dynamic XPath support?

>-----Original Message-----
>From: Duane Gran [mailto:[hidden email]]
>Sent: 02 January 2006 02:23
>To: [hidden email]
>Subject: [ops-users] Dynamic XPath support?
>
>First off, many thanks for the advice offered on the list concerning
>my previous message (Manipulating the order of elements).  I have a
>prototype working very well, using XUpdate with some hard-coded
>values, but I'm running into what I believe is a common frustration
>with XPath -- the lack of dynamic xpath expressions.  Let me show an
>example of my input document:
>
><form>
>     <xpath>/form/document/mods/titleInfo/subTitle</xpath>
>     <document>
>         <mods>
>             <titleInfo>
>                 <title>Sound and fury</title>
>                 <subTitle>my sub title</subTitle>
>             </titleInfo>
>          </mods>
>     </document>
></form>
>
>I'm trying to create an XUpdate variable ($sub) which uses the data
>found in /form/xpath.  I'm trying the following without success:
>
><xu:variable name="path-to-node" select="/form/xpath"/>
><xu:variable name="sub" select="$path-to-node"/>
>
>I've also tried select="/form/xpath/text()" with no luck -- all
>xu:remove and xu:insert* commands fail silently.  I found the
>following third-party effort to support dynamic XPath, which has an
>evaluate() method to address this issue:
>
>   http://www.exslt.org/dyn/index.html
>
>I believe Saxon has an evaluate() method as well.  My question is
>whether OPS has any support for this feature?  When I try to use the
>evalute() function I get an exception stating "Unsupported type:
>org.jaxen.function.ext.EvaluateFunction".
>
>Duane Gran

> First off, many thanks for the advice offered on the list concerning  my
> previous message (Manipulating the order of elements).  I have a  
> prototype working very well, using XUpdate with some hard-coded  values,
> but I'm running into what I believe is a common frustration  with XPath
> -- the lack of dynamic xpath expressions.  Let me show an  example of my
> input document:
>
> <form>
>     <xpath>/form/document/mods/titleInfo/subTitle</xpath>
>     <document>
>         <mods>
>             <titleInfo>
>                 <title>Sound and fury</title>
>                 <subTitle>my sub title</subTitle>
>             </titleInfo>
>          </mods>
>     </document>
> </form>
>
> I'm trying to create an XUpdate variable ($sub) which uses the data  
> found in /form/xpath.  I'm trying the following without success:
>
> <xu:variable name="path-to-node" select="/form/xpath"/>
> <xu:variable name="sub" select="$path-to-node"/>
>
> I've also tried select="/form/xpath/text()" with no luck -- all  
> xu:remove and xu:insert* commands fail silently.  I found the  following
> third-party effort to support dynamic XPath, which has an  evaluate()
> method to address this issue:
>
>   http://www.exslt.org/dyn/index.html
>
> I believe Saxon has an evaluate() method as well.  My question is  
> whether OPS has any support for this feature?  When I try to use the  
> evalute() function I get an exception stating "Unsupported type:  
> org.jaxen.function.ext.EvaluateFunction".
>
> Duane Gran

> Duane,
>
> With Saxon, you can use saxon:evaluate(). With EXSLT, dyn:evaluate
> (). Both should work with Saxon, and dyn:evaluate() should work  
> with pretty much any XSLT processor out there that implements EXSLT  
> extensions, including Saxon and Xalan. Don't forget to map the  
> "saxon" or "dyn" namespaces correctly.
>
> The XUpdate processor uses Jaxen to perform XPath evaluations. I  
> believe that Jaxen supports the dyn:evaluate() function, so you may  
> want to give this a try (obviously saxon:evaluate() will not work  
> in this case). If that doesn't work, you could use an additional  
> step with XSLT to evaluate the XPath expression.
>
> -Erik
>
> Duane Gran wrote:
>> First off, many thanks for the advice offered on the list  
>> concerning  my previous message (Manipulating the order of  
>> elements).  I have a  prototype working very well, using XUpdate  
>> with some hard-coded  values, but I'm running into what I believe  
>> is a common frustration  with XPath -- the lack of dynamic xpath  
>> expressions.  Let me show an  example of my input document:
>> <form>
>>     <xpath>/form/document/mods/titleInfo/subTitle</xpath>
>>     <document>
>>         <mods>
>>             <titleInfo>
>>                 <title>Sound and fury</title>
>>                 <subTitle>my sub title</subTitle>
>>             </titleInfo>
>>          </mods>
>>     </document>
>> </form>
>> I'm trying to create an XUpdate variable ($sub) which uses the  
>> data  found in /form/xpath.  I'm trying the following without  
>> success:
>> <xu:variable name="path-to-node" select="/form/xpath"/>
>> <xu:variable name="sub" select="$path-to-node"/>
>> I've also tried select="/form/xpath/text()" with no luck -- all  
>> xu:remove and xu:insert* commands fail silently.  I found the  
>> following third-party effort to support dynamic XPath, which has  
>> an  evaluate() method to address this issue:
>>   http://www.exslt.org/dyn/index.html
>> I believe Saxon has an evaluate() method as well.  My question is  
>> whether OPS has any support for this feature?  When I try to use  
>> the  evalute() function I get an exception stating "Unsupported  
>> type:  org.jaxen.function.ext.EvaluateFunction".
>> Duane Gran
>
>
> --
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> For general help: mailto:[hidden email]?subject=help
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> wws

> Erik,
>
> Thanks for the pointer.  I added the namespace (xmlns:dyn="http://
> exslt.org/dynamic") and when issuing a call to dyn:evaluate(/my/ xpath)
> OPS throws a Jaxen exeption.  Below is a snippet:
>
> org.jaxen.UnresolvableException: Function dyn:evaluate
>         at org.jaxen.SimpleFunctionContext.getFunction
> (SimpleFunctionContext.java:142)
>         at org.orbeon.oxf.transformer.xupdate.statement.Utils$5.call
> (Utils.java:149)
>
> This implies to me that Jaxen isn't configured to handle EXSLT  
> functions.  I found the following explanation for how to set it up on  
> the Java side:
>
>   http://jaxen.org/extensions.html
>
> Before I dig into the cvs to try this out myself (and contribute it  
> back, if desired) do you think I'm correct in my assessment of the  
> situation?  Also, I sense some negative tone about using XUpdate.  
> Would I be wiser to move the nodes with XSLT?
>
> Duane
>
> On Jan 2, 2006, at 4:54 PM, Erik Bruchez wrote:
>
>> Duane,
>>
>> With Saxon, you can use saxon:evaluate(). With EXSLT, dyn:evaluate ().
>> Both should work with Saxon, and dyn:evaluate() should work  with
>> pretty much any XSLT processor out there that implements EXSLT  
>> extensions, including Saxon and Xalan. Don't forget to map the  
>> "saxon" or "dyn" namespaces correctly.
>>
>> The XUpdate processor uses Jaxen to perform XPath evaluations. I  
>> believe that Jaxen supports the dyn:evaluate() function, so you may  
>> want to give this a try (obviously saxon:evaluate() will not work  in
>> this case). If that doesn't work, you could use an additional  step
>> with XSLT to evaluate the XPath expression.
>>
>> -Erik
>>
>> Duane Gran wrote:
>>
>>> First off, many thanks for the advice offered on the list  
>>> concerning  my previous message (Manipulating the order of  
>>> elements).  I have a  prototype working very well, using XUpdate  
>>> with some hard-coded  values, but I'm running into what I believe  is
>>> a common frustration  with XPath -- the lack of dynamic xpath  
>>> expressions.  Let me show an  example of my input document:
>>> <form>
>>>     <xpath>/form/document/mods/titleInfo/subTitle</xpath>
>>>     <document>
>>>         <mods>
>>>             <titleInfo>
>>>                 <title>Sound and fury</title>
>>>                 <subTitle>my sub title</subTitle>
>>>             </titleInfo>
>>>          </mods>
>>>     </document>
>>> </form>
>>> I'm trying to create an XUpdate variable ($sub) which uses the  data  
>>> found in /form/xpath.  I'm trying the following without  success:
>>> <xu:variable name="path-to-node" select="/form/xpath"/>
>>> <xu:variable name="sub" select="$path-to-node"/>
>>> I've also tried select="/form/xpath/text()" with no luck -- all  
>>> xu:remove and xu:insert* commands fail silently.  I found the  
>>> following third-party effort to support dynamic XPath, which has  an  
>>> evaluate() method to address this issue:
>>>   http://www.exslt.org/dyn/index.html
>>> I believe Saxon has an evaluate() method as well.  My question is  
>>> whether OPS has any support for this feature?  When I try to use  
>>> the  evalute() function I get an exception stating "Unsupported  
>>> type:  org.jaxen.function.ext.EvaluateFunction".
>>> Duane Gran

> Duane,
>
> I guess the "dyn:evaluate" function is not hooked up by default. FWIW,
> the XUpdate processor uses Dom4jUtils.createXPath() to create XPath
> expressions, which is not the "modern" to do this in OPS anymore.
>
> However I found out that we do hook-up a proprietery "evaluate" function
> in the XUpdate processor, called simply "evaluate". It takes three
> arguments:
>
> 1. The XPath expression to evaluate (string)
> 2. A list of namespaces in scope (namespace nodes)
> 3. A context node (node)
>
> Example:
>
> <xu:value-of select="evaluate('123',
>      /*/my-context-node/namespace::*,
>      /*/my-context-node)"/>
>
> You can give this a try.
>
> -Erik
>
> Duane Gran wrote:
> > Erik,
> >
> > Thanks for the pointer.  I added the namespace (xmlns:dyn="http://
> > exslt.org/dynamic") and when issuing a call to dyn:evaluate(/my/ xpath)
> > OPS throws a Jaxen exeption.  Below is a snippet:
> >
> > org.jaxen.UnresolvableException: Function dyn:evaluate
> >         at org.jaxen.SimpleFunctionContext.getFunction
> > (SimpleFunctionContext.java:142)
> >         at org.orbeon.oxf.transformer.xupdate.statement.Utils$5.call
> > (Utils.java:149)
> >
> > This implies to me that Jaxen isn't configured to handle EXSLT
> > functions.  I found the following explanation for how to set it up on
> > the Java side:
> >
> >   http://jaxen.org/extensions.html
> >
> > Before I dig into the cvs to try this out myself (and contribute it
> > back, if desired) do you think I'm correct in my assessment of the
> > situation?  Also, I sense some negative tone about using XUpdate.
> > Would I be wiser to move the nodes with XSLT?
> >
> > Duane
> >
> > On Jan 2, 2006, at 4:54 PM, Erik Bruchez wrote:
> >
> >> Duane,
> >>
> >> With Saxon, you can use saxon:evaluate(). With EXSLT, dyn:evaluate ().
> >> Both should work with Saxon, and dyn:evaluate() should work  with
> >> pretty much any XSLT processor out there that implements EXSLT
> >> extensions, including Saxon and Xalan. Don't forget to map the
> >> "saxon" or "dyn" namespaces correctly.
> >>
> >> The XUpdate processor uses Jaxen to perform XPath evaluations. I
> >> believe that Jaxen supports the dyn:evaluate() function, so you may
> >> want to give this a try (obviously saxon:evaluate() will not work  in
> >> this case). If that doesn't work, you could use an additional  step
> >> with XSLT to evaluate the XPath expression.
> >>
> >> -Erik
> >>
> >> Duane Gran wrote:
> >>
> >>> First off, many thanks for the advice offered on the list
> >>> concerning  my previous message (Manipulating the order of
> >>> elements).  I have a  prototype working very well, using XUpdate
> >>> with some hard-coded  values, but I'm running into what I believe  is
> >>> a common frustration  with XPath -- the lack of dynamic xpath
> >>> expressions.  Let me show an  example of my input document:
> >>> <form>
> >>>     <xpath>/form/document/mods/titleInfo/subTitle</xpath>
> >>>     <document>
> >>>         <mods>
> >>>             <titleInfo>
> >>>                 <title>Sound and fury</title>
> >>>                 <subTitle>my sub title</subTitle>
> >>>             </titleInfo>
> >>>          </mods>
> >>>     </document>
> >>> </form>
> >>> I'm trying to create an XUpdate variable ($sub) which uses the  data
> >>> found in /form/xpath.  I'm trying the following without  success:
> >>> <xu:variable name="path-to-node" select="/form/xpath"/>
> >>> <xu:variable name="sub" select="$path-to-node"/>
> >>> I've also tried select="/form/xpath/text()" with no luck -- all
> >>> xu:remove and xu:insert* commands fail silently.  I found the
> >>> following third-party effort to support dynamic XPath, which has  an
> >>> evaluate() method to address this issue:
> >>>   http://www.exslt.org/dyn/index.html
> >>> I believe Saxon has an evaluate() method as well.  My question is
> >>> whether OPS has any support for this feature?  When I try to use
> >>> the  evalute() function I get an exception stating "Unsupported
> >>> type:  org.jaxen.function.ext.EvaluateFunction".
> >>> Duane Gran
>
>
>
>
> --
> You receive this message as a subscriber of the [hidden email] mailing list.
> To unsubscribe: mailto:[hidden email]
> For general help: mailto:[hidden email]?subject=help
> ObjectWeb mailing lists service home page: http://www.objectweb.org/wws
>
>
>