[ODE-71] AsyncProcess2 test ported to Axis2 deployment not functioning properly do to an error when evaluating the XPath10 expression

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0-incubating
• Fix Version/s: 1.1
• Component/s: BPEL Compilation/Parsing, BPEL Runtime
• Environment: win32_x86, windows xp, Tomcat with ode's generated axis2 war, debugging with Eclipse dev environment
• Assignee: Matthieu Riou
• Reporter: Dave MacLean
• Created: 19/Oct/06 20:11
• Updated: 09/Aug/07 23:18
• Resolved: 09/Aug/07 23:18

Description

(Pasting post from mailing list, will attach unit test in a zip)

Following up, I think a more correct change would be to pursue what I listed as "a)" below:

In org.apache.ode.bpel.engine.BpelRuntimeContextImpl, under the method "getPartData", we currently have the code:

public Node getPartData(Element message, Part part) {
Element partEl = DOMUtils.findChildByName(
(Element) message,
new QName(null, part.name),
false);

if (partEl == null)
return null;

Node container = DOMUtils.getFirstChildElement(partEl);

if (container == null)
container = partEl.getFirstChild(); // either a text node / element

return container;
}

This seems incorrect. Shouldn't part data return the actual part and not the part's first child?

I would propose to change this to:

public Node getPartData(Element message, Part part)

{ return DOMUtils.findChildByName( (Element) message, new QName(null, part.name), false); }

For a wsdl that contains a message like this:

<message name="ProcessInputMessage">
<part name="payload" element="typ:AllOrders"/>
</message>

The dom-parsed xml structure ends up looking like:

<?xml version="1.0" encoding="UTF-8"?>
<message>
<payload>
<AllOrders xmlns="uri:com.bptest.types">
<Order>
<OrderId>1161286397524-1</OrderId>
<OrderType>BookOrder</OrderType>
<!-- etc... -->

The current version of the method getPartData method returns the "AllOrders" tag, the proposed version would return the "payload" tag.
Does this make sense? With this change, the xpath evaluation works correctly, since when the XPath10 libaries start their evaluation of "/typ:AllOrders" on the first child of "payload", it matches "AllOrders"
correctly.

I guess it just makes more sense that "getPartData" would actually get the part instead of getting the part's first child...

Any comments on this?

Thanks,

Dave

----Original Message----
From: Dave MacLean [e-mail]
Sent: Thursday, October 19, 2006 12:06 PM
To: [e-mail]
Subject: XPath10 expression evaluation and the AsyncProcess2 example - potential fix

Hello,
I've been working on getting the AsyncProcess2 example to work under an axis 2 deployment, and I think I ran into a bug.

The xpath evaluation was failing when trying to evaluate this "from"
line of the first assign in the bpel:

<from
expressionLanguage="urn:oasis:names:tc:wsbpel:2.0:sublang:xpath1.0">
count(bpws:getVariableData('Input', 'payload',
'/typ:AllOrders')/typ:Order)
</from>

In particular, it had trouble evaluating the /typ:AllOrders expression.
The actual xml I'm using for the soap message is the one that appears in subversion for the example, and starts like this:

<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
<SOAP-ENV:Body>
<AllOrders xmlns="uri:com.bptest.types">
<Order >
<!-- etc... -->

Tracing into
org.apache.ode.bpel.elang.xpath10.runtime.XPath10ExpressionRuntime, in the createContext method, the code instantiates a new ContextSupport with a BpelDocumentNavigator created using:

new BpelDocumentNavigator(ctx.getRootNode())

where ctx is the EvaluationContext passed in.

The problem is the root node returned here points to the AllOrders element. That would appear to be ok, but when tracing into the jaxen evaluation later on, it starts comparisons with the first child of the root node given - That is, the order of the nodes returned by the AxisNodeIterator used in the jaxen source never returns the root node itself, just the children and siblings.

This leads to the first comparison being against that first "<Order>"
tag, which causes no matches to occur and an empty array resulting from the evaluation (when it should match that first "<AllOrders>" tag and return that one match. Since I'm assuming the jaxen evaluation code is correct, it looks like we need to have some document wrapping the root node in this case or we need to have the EvaluationContext's root node returning a "parent" node of the node we're actually interested in...

For example, changing the createContext method to the below did fix the problem I was having (but I'm worried this exact change may cause other unexpected behavior):

private Context createContext(OXPath10Expression oxpath, EvaluationContext ctx) {
JaxenContexts bpelSupport = new JaxenContexts(oxpath, _extensionFunctions, ctx);
Node rootNode = ctx.getRootNode();
if (rootNode!=null && rootNode.getParentNode()!=null)

{ rootNode = rootNode.getParentNode(); }

ContextSupport support = new ContextSupport(new JaxenNamespaceContextAdapter(oxpath.namespaceCtx),
bpelSupport, bpelSupport,
new BpelDocumentNavigator(rootNode));
Context jctx = new Context(support);

if (ctx.getRootNode() != null)
jctx.setNodeSet(Collections.singletonList(ctx.getRootNode()));

return jctx;
}

Basically, it just sets the BpelDocumentNavigator to use the parent node of the root node returned by the EvaluationContext, if available. With this change and a proper deploy.xml file (and a few minor wsdl changes), the AsyncProcess2 example runs and returns correctly in the Axis2 environment.

Can any one provide guidance on the "proper" way to be doing something equivalent?

a) Should the EvaluationContext.getRootNode() method return a wrapping document/parent node?

Or,
b) Should we be doing something like I have above, where we pass in the proper root node when creating the navigator?

Or,
c) Should the navigator somehow be modified so that it uses the correct root node when calling the jaxen libraries to find matches to the expression?

I'm going to attach another thread below that might be related to this
same issue, although it's related to XPath20 and not XPath10.

Thanks in advance,

Dave

From "Matthieu Riou" <[e-mail]>
Subject Re: XPath 20
Date Tue, 19 Sep 2006 17:45:38 GMT

Ok, I've found it. Your part is a type, not an element. And the
expression
$request.requestMessageData points to the part itself, any XPath
expression
will therefore be evaluated on the nodeset of the part child nodes. So
the
full expression should be $request.requestMessageData/requestID, you
don't
need to repeat the part name in there as there's no element for it.

On 9/18/06, Lance Waterman <[e-mail]> wrote:
>
>
>
> On 9/18/06, Matthieu Riou <[e-mail]> wrote:
>
> > Hi Lance,
> >
> > See my comments inline...
> >
> > 1) XPath20ExpressionRuntime ( line 173 )
> > >
> > > Object evalResult =
expr.evaluate(DOMUtils.newDocument(),
> > > type);
> > >
> > > Does this imply that all xpath syntax must contain a variable
> > reference?
> >
> >
>