Re: XPath 2.0 support for Synapse

[Kasun Indrasiri <ka...@gmail.com>]

+1 for adding XPath 2.0 support.

On Mon, Jul 25, 2011 at 11:23 AM, Heshan Suriyaarachchi <
heshan.suriyaarachchi@gmail.com> wrote:

> Thanks Indika and Andreas for the feedback. Let's see what others have to
> say about $subject.
>
> On Sun, Jul 24, 2011 at 5:56 AM, indika kumara <in...@gmail.com>wrote:
>
>> Thank Andreas for the detailed information.
>>
>> I think the option 2 is great but seems a long-term solution.  The
>> option 1 is an acceptable solution if there is an XPATH 2.0 engine
>> supporting custom object models effectively.
>>
>> ~ Indika
>>
>> On Sun, Jul 24, 2011 at 2:23 AM, Andreas Veithen
>> <an...@gmail.com> wrote:
>> > Axiom uses Jaxen for its XPath support because Jaxen has an
>> > abstraction layer that allows to plug in any object model. The
>> > javax.xml.xpath API is also designed to support multiple object
>> > models, however AFAIK existing implementations only support DOM. That
>> > means that one would have to convert the entire message to DOM every
>> > time an XPath expression is evaluated. Obviously that is not a good
>> > thing to do.
>> >
>> > Since building and maintaining an XPath 2.0 implementation is out of
>> > the scope of the Axiom project, this leaves us with two reasonable
>> > options:
>> >
>> > 1. Find an existing XPath 2.0 implementation that has the same level
>> > of object model independence as Jaxen. If such an implementation
>> > exists, one would only have to write the glue code to integrate it
>> > with Axiom.
>> >
>> > 2. Use an Axiom implementation that not only implements enough of the
>> > Axiom API to support the Axis2 and Synapse runtime, but also provides
>> > a decent implementation of the DOM API so that an existing
>> > implementation of the javax.xml.xpath API can be used. This is not the
>> > case for DOOM: it doesn't implement the Axiom API well enough to run
>> > Axis2. I've been working for some time on a project [1] that provides
>> > this kind of implementation. It is making steady progress, but it is
>> > still very experimental and is only able to run some parts of the
>> > Axis2 runtime.
>> >
>> > Andreas
>> >
>> > [1] http://code.google.com/p/ddom/
>> >
>> > On Fri, Jul 15, 2011 at 05:01, indika kumara <in...@gmail.com>
>> wrote:
>> >> Heshan, I think the better option is to use the standard
>> >> javax.xml.xpath API, and try to avoid AXIOMXPath.  It seems that saxon
>> >> supports javax.xml.xpath API. It should be a matter of configuring a
>> >> property to force to use Saxon implementation - just like XSLT
>> >> transformation, Schema validation.
>> >>
>> >> There may be a trade-off between flexibility and performance with the
>> >> selection of a standard API or AXIOMXPath. However, with OMSource
>> >> [3-4] or similar thing, you should be able to plug AXIOM XML model to
>> >> the XPATH engine in a standard way. So, effectively, you may be able
>> >> to get any performance gain (if there are) from the use of AXIOMXPath
>> >> with the standard way too.  BTW, anything needs to be validated.
>> >>
>> >> Thanks,
>> >>
>> >> Indika
>> >>
>> >> [1]
>> http://download.oracle.com/javase/1.5.0/docs/api/javax/xml/xpath/package-frame.html
>> >> [2] http://www.saxonica.com/documentation/javadoc/index.html
>> >> [3]
>> http://svn.apache.org/viewvc/synapse/trunk/java/modules/core/src/main/java/org/apache/synapse/util/jaxp/
>> >> [4]
>> http://ws.apache.org/axiom/apidocs/org/apache/axiom/om/impl/jaxp/OMSource.html
>> >>
>> >> On Fri, Jul 15, 2011 at 12:15 PM, Heshan Suriyaarachchi
>> >> <he...@gmail.com> wrote:
>> >>> Hi Devs,
>> >>> Synapse currently does not support XPath 2.0. I am looking into a way
>> of
>> >>> adding this support for Synapse.
>> >>> SynapseXPath is written by extending AXIOMXPath which is using Jaxen.
>> Jaxen
>> >>> does not support XPath 2.0. That is the reason that we can not use
>> XPath 2.0
>> >>> in Synapse.
>> >>> I would like to get your valuable feedback on the way to go with
>> $subject.
>> >>>
>> >>> [1]
>> >>> -
>> http://mail-archives.apache.org/mod_mbox/ws-dev/201107.mbox/%3CCAMtOT2qSuF2vB7pas_HLN29_k3aNWnYWycEoLQ_S6yGtAaSihA@mail.gmail.com%3E
>> >>> [2] - https://issues.apache.org/jira/browse/AXIOM-367
>> >>> --
>> >>> Regards,
>> >>> Heshan Suriyaarachchi
>> >>>
>> >>> http://heshans.blogspot.com/
>> >>>
>> >>
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>> >>
>> >>
>> >
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>> >
>>
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>>
>
>
> --
> Regards,
> Heshan Suriyaarachchi
>
> http://heshans.blogspot.com/
>



-- 
Kasun Indrasiri
Senior Software Engineer,
WSO2 Inc. - "Lean . Enterprise . Middleware" - http://www.wso2.com/
Blog : http://kasunpanorama.blogspot.com/