Bpelc issues with WSDL schema definition

Question

Hi,
I have been attempting to deploy a relative simple BPEL example, developed using the BPEL Designer Eclipse plugin and deployed on BPEL Process Manager.
The BPEL consists of receiving a SOAP message, copying variables using assign from the input message to a message defined in an external WSDL, invoking that WSDL's service and copying the results of that service into the output message.
To design the external service, I developed a simple Java class in Apache Axis and used the Java2WSDL tool to create all the interfaces. I then copied that WSDL to the BPEL designer and started to design the BPEL.
The problem is to do with the definition of messages within the WSDL, the following snippet is from the WSDL generated in Apache Axis:
<wsdl:types>
<schema xmlns="http://www.w3.org/2001/XMLSchema"
     targetNamespace="http://mdsuk.com/wsdl/example/PSP1">
<import namespace="http://schemas.xmlsoap.org/soap/encoding/"/>
<complexType name="OutputCT">
<sequence>
<element name="message" nillable="true" type="xsd:string"/>
<element name="paymentReference" nillable="true" type="xsd:string"/>
<element name="success" nillable="true" type="xsd:boolean"/>
</sequence>
</complexType>
</schema>
</wsdl:types>
I then tried to create the <assign> statement for the External Service Message -> BPEL Output Message using BPEL Designer using the visual editor, it generated the following code:
<assign name="assign-2">
<copy>
     <from variable="pspOutput" part="outputCT" query="/message"></from>
     <to variable="output" part="payload" query="/tns:OrderTestResponse/tns:result"/>
</copy>
<copy>
     <from variable="pspOutput" part="outputCT" query="/success"></from>
     <to variable="output" part="payload" query="/tns:OrderTestResponse/tns:success"/>
</copy>
</assign>
Trying to compile this generated code resulted in:
[bpelc] [Error ORABPEL-10057]: invalid query
[bpelc] [Description]: in line 94 of "D:\EclipseWorkspace\OrderTest\OrderTest.bpel", query "/message" is invalid, because step 'message' is not valid..
[bpelc] [Potential fix]: Check the XML schema and make sure your query string is valid.
[bpelc]
[bpelc] [Error ORABPEL-10057]: invalid query
[bpelc] [Description]: in line 98 of "D:\EclipseWorkspace\OrderTest\OrderTest.bpel", query "/success" is invalid, because step 'success' is not valid..
[bpelc] [Potential fix]: Check the XML schema and make sure your query string is valid.
So, the generated code from BPEL Designer was failing to compile. This resulted in a long check of the code, finally I realised that it expected the inputCT variable to be present in the XPath, so I manually changed the code to
<assign name="assign-2">
<copy>
     <from variable="pspOutput" part="outputCT" query="/outputCT/message"></from>
     <to variable="output" part="payload" query="/tns:OrderTestResponse/tns:result"/>
</copy>
<copy>
     <from variable="pspOutput" part="outputCT" query="/outputCT/success"></from>
     <to variable="output" part="payload" query="/tns:OrderTestResponse/tns:success"/>
</copy>
</assign>
This allowed to code to compile, so I deployed the BPEL to the Process Manager, and invoked a query using the Web Interface.
The BPEL started up fine, it invoked my external Axis Web Service, Axis produced the output (visible via debugging) however Process Manager tried to process the output, it crashed with the following exception:
06/01/19 16:29:11 com.oracle.bpel.client.BPELFault: faultName: {{http://schemas.xmlsoap.org/ws/2003/03/business-process/}selectionFailure}
messageType: {null}
parts: {{summary=<summary>empty variable/expression result.
xpath variable/expression expression "/outputCT/message" is empty at line 94, when attempting reading/copying it.
Please make sure the variable/expression result "/outputCT/message" is not empty.
</summary>}}
So, the compiled BPEL code, which had the WSDL schema to compare against was failing during execution, I inspected the output from the Axis Web Service, which was:
<?xml version="1.0" encoding="utf-8"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<soapenv:Body>
<processPaymentResponse xmlns="http://mdsuk.com/wsdl/example/PSP1">
<outputCT xmlns="">
<ns1:message xmlns:ns1="http://mdsuk.com/wsdl/example/PSP1">Payment Succesful</ns1:message>
<ns2:paymentReference xmlns:ns2="http://mdsuk.com/wsdl/example/PSP1">1137688175137</ns2:paymentReference>
<ns3:success xmlns:ns3="http://mdsuk.com/wsdl/example/PSP1">true</ns3:success>
</outputCT>
</processPaymentResponse>
</soapenv:Body>
</soapenv:Envelope>
The key difference was that the message / paymentReference and success attributes were prefixed with the namespace "http://mdsuk.com/wsdl/example/PSP1" , this makes sense as the schema has the attribute targetNamespace="http://mdsuk.com/wsdl/example/PSP1".
However, when I tried to modify the BPEL to read:
<assign name="assign-2">
<copy>
     <from variable="pspOutput" part="outputCT" query="/outputCT/nsxml1:message"></from>
     <to variable="output" part="payload" query="/tns:OrderTestResponse/tns:result"/>
</copy>
<copy>
     <from variable="pspOutput" part="outputCT" query="/outputCT/nsxml1:success"></from>
     <to variable="output" part="payload" query="/tns:OrderTestResponse/tns:success"/>
</copy>
</assign>
It complained:
[bpelc] [Error ORABPEL-10057]: invalid query
[bpelc] [Description]: in line 94 of "D:\EclipseWorkspace\OrderTest\OrderTest.bpel", query "/outputCT/nsxml1:message" is invalid, because step 'nsxml1:message' is not valid..
[bpelc] [Potential fix]: Check the XML schema and make sure your query string is valid.
[bpelc]
[bpelc] [Error ORABPEL-10057]: invalid query
[bpelc] [Description]: in line 98 of "D:\EclipseWorkspace\OrderTest\OrderTest.bpel", query "/outputCT/nsxml1:sucess" is invalid, because step 'nsxml1:sucess' is not valid..
[bpelc] [Potential fix]: Check the XML schema and make sure your query string is valid.
[bpelc] .
So, the BPEL would not validate against the WSDL schema that was being produced, I read up on the W3 Schema specification, and found that the schema can take the attribute elementFormDefault - this attribute takes the values 'qualified' or 'unqualified'. If qualified, then it explicitly states that all children elements should be beloning to the namespace of this element.
So, I changed the schema to read:
<wsdl:types>
<schema xmlns="http://www.w3.org/2001/XMLSchema"
     targetNamespace="http://mdsuk.com/wsdl/example/PSP1"
     elementFormDefault="qualified">
<import namespace="http://schemas.xmlsoap.org/soap/encoding/"/>
<complexType name="OutputCT">
<sequence>
<element name="message" nillable="true" type="xsd:string"/>
<element name="paymentReference" nillable="true" type="xsd:string"/>
<element name="success" nillable="true" type="xsd:boolean"/>
</sequence>
</complexType>
</schema>
</wsdl:types>
The BPEL compiled and ran succesfully.
However, the problem/issue here is, Oracle bpelc assumed that if the elementFormDefault attribute was missing from the schema definition, it defaulted to unqualified, even with the targetNamespace attribute present.
Axis and <oXygen/> XML Editors, in which I tested the WSDL code, assumed that if the elementFormDefault attribute was missing, it defaulted to qualified.
I cannot find anything in the Schema Specification to say which is correct - can anyone shed any light on this? I also want to make Oracle BPEL users aware of this issue.
Regards,
Peter Dolukhanov

Answer 1

I resolved this issue by adding the following to the 2nd schema in the wsdl
xmlns:xsdLocal1="urn:/crmondemand/xml/integrationevent"
inside the 2nd schema
<xsd:schema
elementFormDefault="qualified"
attributeFormDefault="unqualified"
xmlns:xsdLocal1="urn:/crmondemand/xml/integrationevent"
targetNamespace="urn:crmondemand/ws/integrationevent/" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
and this line immediately below it
<xsd:import namespace="urn:/crmondemand/xml/integrationevent" />
I could then create a proxy class using wsdl.exe