System faults can be handle by setting an exception object by invoking following api:

javax.jbi.messaging.MessageExchange

public void setError(java.lang.Exception error)

The getMessage() method on java.lang.Exception will return an xml instance document which confirm to following xsd:

System Fault Schema

The schema describe a SystemFault element which has version attribute and following child elements:

1. code
2. subcode
3. reason
4. node
5. role
6. detail

The version attribute allow us to evolve the structure of the System Faults.

The description of these elements is shown in the xsd documentation.

Following is a snippet of SystemFault from the schema:

  <xsd:element name="SystemFault" type="tns:SystemFaultType"/$gt;

   
   <xsd:complexType name="SystemFaultType" final="extension">
  <xsd:sequence>
   
   <xsd:element name="code" type="tns:CodeType" minOccurs="0">
    <xsd:annotation>
     <xsd:documentation>
         This would be specify either sender/receiver. 
         sender indicates that component who is setting this error wants to convey that error is due to something wrong at 
         the sender of a message exchange.Example sender has sent wrong message. 
         
         receiver indicates that component who is setting this error wants to convey that error is due to something wrong at 
         this component of a message exchange. Example: receiver can not process message due to some internal error. 
         
     </xsd:documentation>
    </xsd:annotation>
   </xsd:element> 
    <xsd:element name="subcode" type="xsd:string" minOccurs="0">
     <xsd:annotation>
      <xsd:documentation>This would be specify system fault identifer string. Example: "Timed Out" for s time out system fault.</xsd:documentation>
     </xsd:annotation>
    </xsd:element> 
    
    <xsd:element name="reason" type="xsd:string" minOccurs="0">
     <xsd:annotation>
      <xsd:documentation>This would human readable description of system fault. Example:This task is not complete within 2 days and timed out</xsd:documentation>
     </xsd:annotation>
    </xsd:element> 
    
     <xsd:element name="node" type="xsd:string" minOccurs="0">
     <xsd:annotation>
      <xsd:documentation>
          Which component caused the error. This could be an intermediary component.
          A node (component) is identified by a URI.
      </xsd:documentation>
     </xsd:annotation>
    </xsd:element> 
    
     <xsd:element name="role" type="tns:RoleType" minOccurs="0">
     <xsd:annotation>
      <xsd:documentation>This is optional. identifies the role the node was operating in at the point the fault occurred. 
      Valid values are: 
        next
        none
        ultimateReceiver
     </xsd:documentation>
     </xsd:annotation>
    </xsd:element> 
    
   <xsd:element name="detail" type="tns:DetailType" minOccurs="0">
    <xsd:annotation>
     <xsd:documentation>This would be extra details if any for a fault.</xsd:documentation>
    </xsd:annotation>
   </xsd:element>
  </xsd:sequence>
  <xsd:attribute name="version" type="xsd:string" >
      <xsd:annotation>
     <xsd:documentation>Version is helpful in evolution of the structure of the system faults. If there is a change in system fault, it will have a new version.</xsd:documentation>
    </xsd:annotation>
   
  </xsd:attribute>
 </xsd:complexType>

Task Timeout and System Fault:

On Task Timeout WLMSE will set Error on message exchange by creating an java.lang.Exception object which returns following xml instance document when getMessage() is called.

<SystemFault version="1.0" xmlns="http://java.sun.com/xml/ns/jbi/systemfaults" >
   <code>receiver</code>
   <subcode>Timed Out</subcode>
    <reason>This task is not completed within specified time and timed out </reason>
</SystemFault> 

BPEL SE when receive the Error Exception in the message exchange, can optmize to check if the getMessage starts with <SystemFault is so it can then process the System Fault.

Mapping of System Fault to WSDL Message:

Following is the well known WSDL Message which maps the System Fault to a WSDL Message:

System Fault WSDL Message

Following is the snippet of WSDL Message:

<message name="SystemFaultMessage">
        <wsdl:part name="systemFaultPart" element="ns0:SystemFault"/>
    </message>

upon receiving System Fault BPEL SE can map it to SystemFaultMessage. User can use SystemFaultMessage to catch this specific message and deal it appropriately.

This page (revision-4) was last changed on 30-Aug-07 10:38 AM, -0700 by RiteshAdval.
This page was created on 03-Aug-07 10:42 AM, -0700 by RiteshAdval.

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