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Posted to user@commons.apache.org by Rahul Akolkar <ra...@gmail.com> on 2009/10/26 04:10:04 UTC
Re: [SCXML] XPathEvaluator / Error accessing complex event payload
On Sun, Oct 25, 2009 at 11:47 AM, Jaroslav Pullmann
<ja...@fit.fraunhofer.de> wrote:
> Hello Rahul,
> although not yet officially released I like using the J6 branch
> (commons-scxml-1.0-SNAPSHOT.jar) because of its XPath support.
> Recently I experience problems when accessing the complex event
> payload (Node: <payload><data><status>started</status></data></payload>,
> plain string payload is o.k.)
>
> This works fine with JexlEvaluator:
>
> <transition event="statuschange">
> <log label="Status changed to"
> expr="Data(_eventdata.payload,'/data/status')"/>
> </transition>
>
> but is broken with XPathEvaluator:
>
> <transition event="statuschange">
> <log label="Message" expr="$_eventdata/data/status"/>
> </transition>
>
<snip/>
The two evaluators handle XPath processing differently, so in order to
track down the error below, please say more as to how you obtained the
Node that became the event payload. For example, if the
DocumentBuilder API is used to parse the above XML, I'd expect it to
work in either cases. I would, however, expect the expression when
using the XPath evaluator in this case to be either
"$_eventdata/payload/data/status" or "$_eventdata//data/status" (note
two /s before data). As an aside, for good measure, specifying an
xmlns on payloads is also recommended practice i.e. <payload
xmlns="">...</payload>.
Also say something about the environment and how we're seeing xalan
classes in the traces that aren't repackaged. The J6 branch requires
JDK 1.6 where, for example, I'd expect to see something like
com.sun.org.apache.xpath.internal.XPath as against
org.apache.xpath.XPath in the traces.
In order for us to reproduce this, if you can produce a small JUnit
test case in the Commons SCXML test suite (see existing ones in
src/test/java/...oacse.../xpath) that produces the trace below, that
can also help.
-Rahul
>
> javax.xml.transform.TransformerException: org.apache.xpath.objects.XObject
> incompatible with org.apache.xpath.objects.XNodeSet
> at org.apache.xpath.XPath.execute(Unknown Source)
> at org.apache.xpath.jaxp.XPathExpressionImpl.evaluate(Unknown Source)
> at org.apache.xpath.jaxp.XPathImpl.evaluate(Unknown Source)
> at
> org.apache.commons.scxml.env.xpath.XPathEvaluator.eval(XPathEvaluator.java:90)
> at org.apache.commons.scxml.model.Log.execute(Log.java:107)
> at
> org.apache.commons.scxml.semantics.SCXMLSemanticsImpl.executeActions(SCXMLSemanticsImpl.java:223)
> at
> org.apache.commons.scxml.SCXMLExecutor.triggerEvents(SCXMLExecutor.java:131)
>
> Caused by: java.lang.ClassCastException: org.apache.xpath.objects.XObject
> incompatible with org.apache.xpath.objects.XNodeSet
> at
> org.apache.xpath.axes.FilterExprIteratorSimple.executeFilterExpr(Unknown
> Source)
> at org.apache.xpath.axes.FilterExprWalker.setRoot(Unknown Source)
> at org.apache.xpath.axes.WalkingIterator.setRoot(Unknown Source)
> at org.apache.xpath.axes.NodeSequence.setRoot(Unknown Source)
> at org.apache.xpath.axes.LocPathIterator.execute(Unknown Source)
> ... 13 more
>
>
> Is this may be due to an incorrect variable naming or whichever user
> error ?
>
> Many thanks for your help!
> Jaro
>
>
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Re: [SCXML] XPathEvaluator / Error accessing complex event payload
Posted by Rahul Akolkar <ra...@gmail.com>.
On Tue, Nov 3, 2009 at 6:52 AM, Jaroslav Pullmann
<ja...@fit.fraunhofer.de> wrote:
>
>
> Hello Rahul,
> sorry for the late response, I've been out of office last week.
> I looked at the code once again and found the error cause. The payload
> was in deed wrapped into a bean with a dedicated accessor method
> Node getPayload(), instead of passing the node directly. This worked
> only with the Jexl-evaluator..
>
<snip/>
Cool, makes sense.
-Rahul
> Please find attached the extended test suite for XPath. This may
> be of interest for other users in a comparative documentation of
> the XPath-based access to event payload and data models .
> Best regards
> Jaro
>
>
>
>
> Rahul Akolkar wrote:
>>
>> On Sun, Oct 25, 2009 at 11:47 AM, Jaroslav Pullmann
>> <ja...@fit.fraunhofer.de> wrote:
>>>
>>> Hello Rahul,
>>> although not yet officially released I like using the J6 branch
>>> (commons-scxml-1.0-SNAPSHOT.jar) because of its XPath support.
>>> Recently I experience problems when accessing the complex event
>>> payload (Node: <payload><data><status>started</status></data></payload>,
>>> plain string payload is o.k.)
>>>
>>> This works fine with JexlEvaluator:
>>>
>>> <transition event="statuschange">
>>> <log label="Status changed to"
>>> expr="Data(_eventdata.payload,'/data/status')"/>
>>> </transition>
>>>
>>> but is broken with XPathEvaluator:
>>>
>>> <transition event="statuschange">
>>> <log label="Message" expr="$_eventdata/data/status"/>
>>> </transition>
>>>
>> <snip/>
>>
>> The two evaluators handle XPath processing differently, so in order to
>> track down the error below, please say more as to how you obtained the
>> Node that became the event payload. For example, if the
>> DocumentBuilder API is used to parse the above XML, I'd expect it to
>> work in either cases. I would, however, expect the expression when
>> using the XPath evaluator in this case to be either
>> "$_eventdata/payload/data/status" or "$_eventdata//data/status" (note
>> two /s before data). As an aside, for good measure, specifying an
>> xmlns on payloads is also recommended practice i.e. <payload
>> xmlns="">...</payload>.
>>
>> Also say something about the environment and how we're seeing xalan
>> classes in the traces that aren't repackaged. The J6 branch requires
>> JDK 1.6 where, for example, I'd expect to see something like
>> com.sun.org.apache.xpath.internal.XPath as against
>> org.apache.xpath.XPath in the traces.
>>
>> In order for us to reproduce this, if you can produce a small JUnit
>> test case in the Commons SCXML test suite (see existing ones in
>> src/test/java/...oacse.../xpath) that produces the trace below, that
>> can also help.
>>
>> -Rahul
>>
>>
>>> javax.xml.transform.TransformerException:
>>> org.apache.xpath.objects.XObject
>>> incompatible with org.apache.xpath.objects.XNodeSet
>>> at org.apache.xpath.XPath.execute(Unknown Source)
>>> at org.apache.xpath.jaxp.XPathExpressionImpl.evaluate(Unknown
>>> Source)
>>> at org.apache.xpath.jaxp.XPathImpl.evaluate(Unknown Source)
>>> at
>>>
>>> org.apache.commons.scxml.env.xpath.XPathEvaluator.eval(XPathEvaluator.java:90)
>>> at org.apache.commons.scxml.model.Log.execute(Log.java:107)
>>> at
>>>
>>> org.apache.commons.scxml.semantics.SCXMLSemanticsImpl.executeActions(SCXMLSemanticsImpl.java:223)
>>> at
>>>
>>> org.apache.commons.scxml.SCXMLExecutor.triggerEvents(SCXMLExecutor.java:131)
>>>
>>> Caused by: java.lang.ClassCastException: org.apache.xpath.objects.XObject
>>> incompatible with org.apache.xpath.objects.XNodeSet
>>> at
>>> org.apache.xpath.axes.FilterExprIteratorSimple.executeFilterExpr(Unknown
>>> Source)
>>> at org.apache.xpath.axes.FilterExprWalker.setRoot(Unknown Source)
>>> at org.apache.xpath.axes.WalkingIterator.setRoot(Unknown Source)
>>> at org.apache.xpath.axes.NodeSequence.setRoot(Unknown Source)
>>> at org.apache.xpath.axes.LocPathIterator.execute(Unknown Source)
>>> ... 13 more
>>>
>>>
>>> Is this may be due to an incorrect variable naming or whichever
>>> user
>>> error ?
>>>
>>> Many thanks for your help!
>>> Jaro
>>>
>>>
>
>
> --
> Jaroslav Pullmann
> Web Compliance Center - Fraunhofer FIT
> Schloss Birlinghoven, D-53757 Sankt Augustin, Germany
> Phone: +49-2241-142623 Fax: +49-2241-142065
>
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To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
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Re: [SCXML] XPathEvaluator / Error accessing complex event payload
Posted by Jaroslav Pullmann <ja...@fit.fraunhofer.de>.
Hello Rahul,
sorry for the late response, I've been out of office last week.
I looked at the code once again and found the error cause. The payload
was in deed wrapped into a bean with a dedicated accessor method
Node getPayload(), instead of passing the node directly. This worked
only with the Jexl-evaluator..
Please find attached the extended test suite for XPath. This may
be of interest for other users in a comparative documentation of
the XPath-based access to event payload and data models .
Best regards
Jaro
Rahul Akolkar wrote:
> On Sun, Oct 25, 2009 at 11:47 AM, Jaroslav Pullmann
> <ja...@fit.fraunhofer.de> wrote:
>> Hello Rahul,
>> although not yet officially released I like using the J6 branch
>> (commons-scxml-1.0-SNAPSHOT.jar) because of its XPath support.
>> Recently I experience problems when accessing the complex event
>> payload (Node: <payload><data><status>started</status></data></payload>,
>> plain string payload is o.k.)
>>
>> This works fine with JexlEvaluator:
>>
>> <transition event="statuschange">
>> <log label="Status changed to"
>> expr="Data(_eventdata.payload,'/data/status')"/>
>> </transition>
>>
>> but is broken with XPathEvaluator:
>>
>> <transition event="statuschange">
>> <log label="Message" expr="$_eventdata/data/status"/>
>> </transition>
>>
> <snip/>
>
> The two evaluators handle XPath processing differently, so in order to
> track down the error below, please say more as to how you obtained the
> Node that became the event payload. For example, if the
> DocumentBuilder API is used to parse the above XML, I'd expect it to
> work in either cases. I would, however, expect the expression when
> using the XPath evaluator in this case to be either
> "$_eventdata/payload/data/status" or "$_eventdata//data/status" (note
> two /s before data). As an aside, for good measure, specifying an
> xmlns on payloads is also recommended practice i.e. <payload
> xmlns="">...</payload>.
>
> Also say something about the environment and how we're seeing xalan
> classes in the traces that aren't repackaged. The J6 branch requires
> JDK 1.6 where, for example, I'd expect to see something like
> com.sun.org.apache.xpath.internal.XPath as against
> org.apache.xpath.XPath in the traces.
>
> In order for us to reproduce this, if you can produce a small JUnit
> test case in the Commons SCXML test suite (see existing ones in
> src/test/java/...oacse.../xpath) that produces the trace below, that
> can also help.
>
> -Rahul
>
>
>> javax.xml.transform.TransformerException: org.apache.xpath.objects.XObject
>> incompatible with org.apache.xpath.objects.XNodeSet
>> at org.apache.xpath.XPath.execute(Unknown Source)
>> at org.apache.xpath.jaxp.XPathExpressionImpl.evaluate(Unknown Source)
>> at org.apache.xpath.jaxp.XPathImpl.evaluate(Unknown Source)
>> at
>> org.apache.commons.scxml.env.xpath.XPathEvaluator.eval(XPathEvaluator.java:90)
>> at org.apache.commons.scxml.model.Log.execute(Log.java:107)
>> at
>> org.apache.commons.scxml.semantics.SCXMLSemanticsImpl.executeActions(SCXMLSemanticsImpl.java:223)
>> at
>> org.apache.commons.scxml.SCXMLExecutor.triggerEvents(SCXMLExecutor.java:131)
>>
>> Caused by: java.lang.ClassCastException: org.apache.xpath.objects.XObject
>> incompatible with org.apache.xpath.objects.XNodeSet
>> at
>> org.apache.xpath.axes.FilterExprIteratorSimple.executeFilterExpr(Unknown
>> Source)
>> at org.apache.xpath.axes.FilterExprWalker.setRoot(Unknown Source)
>> at org.apache.xpath.axes.WalkingIterator.setRoot(Unknown Source)
>> at org.apache.xpath.axes.NodeSequence.setRoot(Unknown Source)
>> at org.apache.xpath.axes.LocPathIterator.execute(Unknown Source)
>> ... 13 more
>>
>>
>> Is this may be due to an incorrect variable naming or whichever user
>> error ?
>>
>> Many thanks for your help!
>> Jaro
>>
>>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: user-unsubscribe@commons.apache.org
> For additional commands, e-mail: user-help@commons.apache.org
>
--
Jaroslav Pullmann
Web Compliance Center - Fraunhofer FIT
Schloss Birlinghoven, D-53757 Sankt Augustin, Germany
Phone: +49-2241-142623 Fax: +49-2241-142065