Re: Custom Xpath Selector

[Joerg Heinicke <jo...@gmx.de>]

Hi Richard,

It's actually not possible by design. Matchers, selectors and actions 
are evaluated in the pipeline setup phase to find the pipeline 
components. Only when the setup is finished the pipeline is executed and 
the SAX events sent through the pipeline. That's why you don't have 
access to pipeline content in a selector. Transformer (with access to 
SAX events) and flowscript (splitting the pipeline into 2) are the 2 
already mentioned alternatives.

Joerg

On 23.07.2008 09:04, Richard McKenzie wrote:
> Cheers Peter
> 
> Thanks for the advice, we are trying to avoid using flow script if
> possible. I just thought I'd post the question in case anybody had
> created a selector which did something similar, after decompiling all
> the cocoon selectors I suspected that it was not possible to do
> elegantly.  
> 
> Many Thanks 
> 
> -----Original Message-----
> From: Peter Hunsberger [mailto:peter.hunsberger@gmail.com] 
> Sent: 22 July 2008 16:28
> To: dev@cocoon.apache.org
> Subject: Re: Custom Xpath Selector
> 
> On Tue, Jul 22, 2008 at 10:04 AM, Richard McKenzie
> <Ri...@bbc.co.uk> wrote:
> 
> <snip/>
> 
>> Perhaps I am barking up the wrong tree and a selector is not the best 
>> solution, it would be nice to be able to do different things bassed on
> 
>> the contents of the xml passed through a pipeline
>>
> 
> If you have complicated use cases I suspect you're going to want to use
> a Java transformer to inspect the XML in the pipeline and have it make
> the decisions on what should be done.  This can be done from flow script
> by firing off the pipeline at that point and then inspecting some
> returned result.  I'm not sure about 2.1 but in 2.0 this looks like
> 
>  var sourceURI = "run/_checkXML/";
>     var destinationURI = "xmodule:request-attr:checkXMLresult";
> 
>     var resolver = null;
>     var destination = null;
>     var output = null;
>     try {
>         resolver = cocoon.getComponent(
> Packages.org.apache.cocoon.environment.SourceResolver.ROLE );
>         destination = resolver.resolveURI( destinationURI );
>         output = destination.getOutputStream();
>         cocoon.processPipelineTo( sourceURI, {}, output );
>         output.close();
> 
>         if ( cocoon.request.getAttribute( "checkXMLresult" ) == ...) {
>   //see what happened in the XML checking pipeline
>            // Do whatever should be done based on the results...
> 
>             return true;
>         }
>     }
>     finally {
>         if (destination != null) {
>             resolver.release( destination );
>         }
>         cocoon.releaseComponent( resolver );
>     }
> --
> Peter Hunsberger