12 Using Fault Handling in a BPEL Process

This chapter describes how to use fault handling in a BPEL process. Fault handling allows a BPEL process service component to handle error messages or other exceptions returned by outside web services, and to generate error messages in response to business or runtime faults. You can also define a fault management framework to catch faults and perform user-specified actions defined in a fault policy file.

This chapter includes the following sections:

For additional information on creating fault handling in a SOA composite application, see Oracle Fusion Middleware Tutorial for Running and Building an Application with Oracle SOA Suite.

12.1 Introduction to a Fault Handler

Fault handlers define how the BPEL process service component responds when the web services return data other than what is normally expected (for example, returning an error message instead of a number). An example of a fault handler is where the web service normally returns a credit rating number, but instead returns a negative credit message.

provides an example of how a fault handler sets a credit rating variable to -1000.

Figure 12-1 Fault Handling

Description of Figure 12-1 follows
Description of "Figure 12-1 Fault Handling"

The code segment in Example 12-1 defines the fault handler for this operation in the BPEL file:

Example 12-1 Fault Handler Definition

<faultHandlers>
     <catch faultName="services:NegativeCredit" faultVariable="crError">
      <assign name="crin">
         <copy>
           <from expression="-1000">
           </from>
           <to variable="input" part="payload"
               query="/autoloan:loanApplication/autoloan:creditRating"/>
         </copy>
       </assign>
     </catch>
</faultHandlers>

The faultHandlers tag contains the fault handling code. Within the fault handler is a catch activity, which defines the fault name and variable, and the copy instruction that sets the creditRating variable to -1000.

When you select web services for the BPEL process service component, determine the possible faults that may be returned and set up a fault handler for each one.

12.2 Introduction to BPEL Standard Faults

The Business Process Execution Language for Web Services Specification defines the following standard faults in the namespace of http://schemas.xmlsoap.org/ws/2003/03/business-process/:

  • bindingFault

  • conflictingReceive

  • conflictingRequest

  • correlationViolation

  • forcedTermination

  • invalidReply

  • joinFailure

  • mismatchedAssignmentFailure

  • remoteFault

  • repeatedCompensation

  • selectionFailure

  • uninitializedVariable

Standard faults are defined as follows:

  • Typeless, meaning they do not have associated messageTypes

  • Not associated with any Web Services Description Language (WSDL) message

  • Caught without a fault variable:

    <catch faultName="bpws:selectionFailure">

12.3 Introduction to Categories of BPEL Faults

A BPEL fault has a fault name called a Qname (name qualified with a namespace) and a possible messageType. There are two categories of BPEL faults:

  • Business faults

  • Runtime faults

12.3.1 Business Faults

Business faults are application-specific faults that are generated when there is a problem with the information being processed (for example, when a social security number is not found in the database). A business fault occurs when an application executes a throw activity or when an invoke activity receives a fault as a response. The fault name of a business fault is specified by the BPEL process service component. The messageType, if applicable, is defined in the WSDL. A business fault can be caught with a faultHandler using the faultName and a faultVariable.

<catch faultName="ns1:faultName" faultVariable="varName">

12.3.2 Runtime Faults

Runtime faults are the result of problems within the running of the BPEL process service component or web service (for example, data cannot be copied properly because the variable name is incorrect). These faults are not user-defined, and are thrown by the system. They are generated if the process tries to use a value incorrectly, a logic error occurs (such as an endless loop), a Simple Object Access Protocol (SOAP) fault occurs in a SOAP call, an exception is thrown by the server, and so on.

Several runtime faults are automatically provided. These faults are included in the http://schemas.oracle.com/bpel/extension namespace. These faults are associated with the messageType RuntimeFaultMessage. The WSDL file shown in Example 12-2 defines the messageType:

Example 12-2 messageType Definition

<?xml version="1.0" encoding="UTF-8" ?> 
<definitions name="RuntimeFault"
  targetNamespace="http://schemas.oracle.com/bpel/extension"
  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
  xmlns="http://schemas.xmlsoap.org/wsdl/">

  <message name="RuntimeFaultMessage">
   <part name="code" type="xsd:string" /> 
   <part name="summary" type="xsd:string" /> 
   <part name="detail" type="xsd:string" /> 
  </message>
</definitions>

If a faultVariable (of messageType RuntimeFaultMessage) is used when catching the fault, the fault code can be queried from the faultVariable, along with the fault summary and detail.

12.3.2.1 bindingFault

A bindingFault is thrown inside an activity if the preparation of the invocation fails. For example, the WSDL of the process fails to load. A bindingFault is not retryable. This type of fault usually must be fixed by human intervention.

12.3.2.2 remoteFault

A remoteFault is also thrown inside an activity. It is thrown because the invocation fails. For example, a SOAP fault is returned by the remote service.

12.3.2.3 replayFault

A replayFault replays the activity inside a scope. At any point inside a scope, this fault is migrated up to the scope. The server then re-executes the scope from the beginning.

12.4 Using the Fault Management Framework

Oracle SOA Suite provides a generic fault management framework for handling faults in BPEL processes. If a fault occurs during runtime in an invoke activity in a process, the framework catches the fault and performs a user-specified action defined in a fault policy file associated with the activity. If a fault results in a condition in which human intervention is the prescribed action, you perform recovery actions from Oracle Enterprise Manager Fusion Middleware Control Console. The fault management framework provides an alternative to designing a BPEL process with catch activities in scope activities.

This section provides an overview of the components that comprise the fault management framework.

  • The fault management framework catches all faults (business and runtime) for an invoke activity.

  • A fault policy file defines fault conditions and their corresponding fault recovery actions. Each fault condition specifies a particular fault or group of faults, which it attempts to handle, and the corresponding action for it. A set of actions is identified by an ID in the fault policy file.

  • A set of conditions invokes an action (known as fault policy).

  • A fault policy bindings file associates the policies defined in the fault policy file with the following:

    • SOA composite applications

    • BPEL process and Oracle Mediator service components

    • Reference binding components for BPEL process and Oracle Mediator service components

    The framework looks for fault policy bindings in the same directory as the composite.xml file of the SOA composite application or in a remote location identified by two properties that you set.

    Note:

    A fault policy configured with the fault management framework overrides any fault handling defined in catch activities of scope activities in the BPEL process. The fault management framework can be configured to rethrow the fault handling back to the catch activities.

  • The fault policy file (fault-policies.xml) and fault policy bindings file (fault-bindings.xml) are placed in either of the following locations:

    • In the same directory as the composite.xml file of the SOA composite application.

    • In a different location that is specified with two properties that you add to the composite.xml file. This option is useful if a fault policy must be used by multiple SOA composite applications. This option overrides any fault policy files that are included in the same directory as the composite.xml file. Example 12-3 provides details about these two properties. In this example, the fault policy files are placed into the SOA Metadata Service (MDS) shared area.

      Example 12-3 Fault Policies used by Multiple SOA Composite Applications

      <property
 name="oracle.composite.faultPolicyFile">oramds://apps/faultpolicyfiles/
 fault-policies.xml
</property>
<property
 name="oracle.composite.faultBindingFile">oramds://apps/faultpolicyfiles/
 fault-bindings.xml
</property>

See Chapter 20, "Using Mediator Error Handling" for details about Oracle Mediator fault handling capabilities.

12.4.1 How to Design a Fault Policy

This section describes how to design a fault policy.

Note:

The Facades API enables you to programmatically perform the abort, retry (with a success action), continue, rethrow, and replay recovery options.

12.4.1.1 Understanding How Fault Policy Binding Resolution Works

A fault policy bindings file associates the policies defined in a fault policy file with the SOA composite application or the component (service component or reference binding component). The framework attempts to identify a fault policy binding in the following order:

  • Reference binding component defined in the composite.xml file.

  • BPEL process or Oracle Mediator service component defined in the composite.xml file.

  • SOA composite application defined in the composite.xml file.

During the resolution process, if no action is found that matches the condition, the framework assumes that resolution failed and moves to the next resolution level.

For example, assume an invoke activity faults with faultname="abc". There is a policy binding specified in the fault-binding.xml file:

  • SOA composite application binds to policy-id-1

  • BPEL process or Oracle Mediator service component or reference binding component binds to policy-id-2

In the fault-bindings.xml file, the following bindings are also specified:

  • SOA composite application binds to policy-id-3

  • Reference binding component or service component binds to policy-id-4

The fault management framework behaves as follows:

  • First match the resolve binding (in this case, policy-id-2).

  • If the fault resolution fails, go to the next possible match (policy-id-4).

  • If the fault resolution fails, go to the next possible match (policy-id-3).

  • If the fault resolution fails, go to the next possible match (in this case, policy-id-1).

  • If the fault resolution still fails, the fault is sent to the BPEL fault catch activity.

12.4.1.2 Creating a Fault Policy File for Automated Fault Recovery

  1. Create a fault policy file (for example, named fault-policies.xml). This file includes condition and action sections for performing specific tasks.

  2. Place the file in the same directory as the composite.xml file or place it in a different location and define the oracle.composite.faultPolicyFile property. Example 12-4 provides details.

    Example 12-4 Defining Properties

    <property
 name="oracle.composite.faultPolicyFile">oramds://apps/faultpolicyfiles/
 fault-policies.xml
</property>
<property
 name="oracle.composite.faultBindingFile">oramds://apps/faultpolicyfiles/
 fault-bindings.xml
</property>

  3. Define the condition section of the fault policy file.

    • Note the following details about the condition section:

      • This section provides a condition based on faultName.

      • Multiple conditions may be configured for a faultName.

      • Each condition has one test section (an XPath expression) and one action section.

      • The test section (XPath expression) is evaluated for the fault variable available in the fault.

      • The action section has a reference to the action defined in the same file.

      • You can only query the fault variable available in the fault.

      • The order of condition evaluation is determined by the sequential order in the document.

      Table 12-1 provides examples of condition section use in the fault policy file. All actions defined in the condition section must be associated with an action in the action section.

      Table 12-1 Use of the condition Section in the Fault Policy File

      Condition Example Fault Policy File Syntax

      This condition is checking a fault variable for code = "WSDLFailure"

      An action of ora-terminate is specified.

      		 
      <condition>
  <test>$fault.code="WSDLReading Error"
  </test>
  <action ref="ora-terminate"/>
</condition>

      No test condition is provided. This is a catch all condition for a given faultName.

      		 
      <condition>
   <action ref="ora-rethrow"/>
</condition>

      If the faultName name attribute is missing, this indicates a catch all activity for faults that have any QName.

      		 
      <faultName > . . . </faultName>

  4. Define the action section of the fault policy file. Note that validation of fault policy files is done during deployment. If you change the fault policy, you must redeploy the SOA composite application that includes the fault policy.

    Table 12-2 provides several examples of action section use in the fault policy file. You can provide automated recovery actions for some faults. In all recovery actions except retry and human intervention, the framework performs the actions synchronously.

    Table 12-2 Use of action Section in the Fault Policy File

    Recovery Actions Fault Policy File Syntax

    Retry: Provides the following actions for retrying the activity.

    • Retry a specified number of times.

    • Provide a delay between retries (in seconds).

    • Increase the interval with an exponential back off.

    • Chain to a retry failure action if retry N times fails.

    • Chain to a retry success action if a retry is successful.

    Note: Exponential back off indicates the next retry attempt is scheduled at 2 x the delay, where delay is the current retry interval. For example, if the current retry interval is 2 seconds, the next retry attempt is scheduled at 4, the next at 8, and the next at 16 seconds until the retryCount value is reached.

    		 
    <Action id="ora-retry">
   <Retry>
      <retryCount>3</retryCount>
      <retryInterval>2</retryInterval>
      <exponentialBackoff/>
      <retryFailureAction ref="ora-java"/>
      <retrySuccessAction ref="ora-java"/>
   </Retry>
</Action>

    Note the following details:

    • The framework chains to the retry success action if the retry attempt is successful.

    • If all retry attempts fail, the framework chains to the retry failure action.

    Human Intervention: Causes the current activity to stop processing. You can now go to Oracle Enterprise Manager Fusion Middleware Control Console and perform manual recovery actions on this instance.

    		 
    <Action id="ora-human-intervention">
 <humanIntervention/></Action>

    Terminate Process: Terminates the process

    		 
    <Action id="ora-terminate"><abort/></Action>

    Java Code: Enables you to execute an external Java class.

    returnValue: The implemented Java class must implement a method that returns a string. The policy can chain to a new action based on the returned string.

    For additional information, see Section 12.4.3, "How to Use a Java Action Fault Policy"

    		 
    <Action id="ora-java">
<!-- this is user provided custom java
 class-->
<javaAction className="mypackage.myClass"
 defaultAction="ora-terminate">
   <returnValue value="REPLAY"
    ref="ora-terminate"/>
   <returnValue value="RETRHOW"
    ref="ora-rethrow-fault"/>
   <returnValue value="ABORT"
    ref="ora-terminate"/>
   <returnValue value="RETRY" ref="ora-retry"/>
   <returnValue value="MANUAL"
    ref="ora-human-intervention"/>
</javaAction>
</Action>

    Rethrow Fault: The framework sends the fault to the BPEL fault handlers (catch activities in scope activities). If none are available, the fault is sent up.

    		 
    <Action id="ora-rethrow-fault"><rethrowFault/></Action>

    Replay Scope: Raises a replay fault.

    		 
    <Action id="ora-replay-scope"><replayScope/></Action>

Note:

The preseeded recovery action tag names (ora-retry, ora-human-intervention, ora-terminate, and so on) are only samples. You can substitute these names with ones appropriate to your environment.

Example 12-5 shows a fault policy file with fully-defined condition and action sections.

Notes:

  • Fault policy file names are not restricted to one specific name. However, they must conform to the fault-policy.xsd schema file.

  • Example 12-5 provides an example of catching faults based on fault names. You can also catch faults based on message types, or on both:

    <fault name="myfault" type="fault:faultType">

Example 12-5 Fault Policy File

<?xml version="1.0" encoding="UTF-8"?>
<faultPolicies xmlns="http://schemas.oracle.com/bpel/faultpolicy"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <faultPolicy version="0.0.1" id="FusionMidFaults"
 xmlns:env="http://schemas.xmlsoap.org/soap/envelope/"
 xmlns:xs="http://www.w3.org/2001/XMLSchema"
 xmlns="http://schemas.oracle.com/bpel/faultpolicy"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <Conditions>
      <faultName xmlns:medns="http://schemas.oracle.com/mediator/faults"
 name="medns:mediatorFault">
        <condition>
          <action ref="MediatorJavaAction"/>
        </condition>
      </faultName>
      <faultName xmlns:bpelx="http://schemas.oracle.com/bpel/extension"
 name="bpelx:remoteFault">
        <condition>
          <action ref="BPELJavaAction"/>
        </condition>
      </faultName>
      <faultName xmlns:bpelx="http://schemas.oracle.com/bpel/extension"
 name="bpelx:bindingFault">
        <condition>
          <action ref="BPELJavaAction"/>
        </condition>
      </faultName>
      <faultName xmlns:bpelx="http://schemas.oracle.com/bpel/extension"
 name="bpelx:runtimeFault">
        <condition>
          <action ref="BPELJavaAction"/>
        </condition>
      </faultName>
    </Conditions>
    <Actions>
      <!-- Generics -->
      <Action id="default-terminate">
        <abort/>
      </Action>
      <Action id="default-replay-scope">
        <replayScope/>
      </Action>
      <Action id="default-rethrow-fault">
        <rethrowFault/>
      </Action>
      <Action id="default-human-intervention">
        <humanIntervention/>
      </Action>
      <Action id="MediatorJavaAction">
        <!-- this is user provided class-->
        <javaAction className="MediatorJavaAction.myClass"
 defaultAction="default-terminate">
          <returnValue value="MANUAL" ref="default-human-intervention"/>
        </javaAction>
      </Action>
      <Action id="BPELJavaAction">
        <!-- this is user provided class-->
        <javaAction className="BPELJavaAction.myAnotherClass"
 defaultAction="default-terminate">
          <returnValue value="MANUAL" ref="default-human-intervention"/>
        </javaAction>
      </Action>
    </Actions>
  </faultPolicy>
</faultPolicies>

12.4.1.3 Associating a Fault Policy with Fault Policy Binding

Note:

The fault policy file binding file must be named fault-bindings.xml. This conforms to the fault-bindings.xsd schema file.

  1. Create a fault policy binding file (fault-bindings.xml) that associates the policies defined in the fault policy file with the level of fault policy binding you are using (either a SOA composite application or a component (reference binding component or BPEL process or Oracle Mediator service component).

  2. Place the file in the same directory as the composite.xml file or place it in a remote location and define the oracle.composite.faultBindingFile property as shown in Step 2.

    Example 12-6 shows a fault policy bindings file that associates the fault policies defined in the fault-policies.xml file with the FusionMidFaults SOA composite application.

Example 12-6 fault-buildings.xml File

<?xml version="1.0" encoding="UTF-8" ?>
<faultPolicyBindings version="0.0.1"
 xmlns="http://schemas.oracle.com/bpel/faultpolicy"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <composite faultPolicy="FusionMidFaults"/>
    <!--<composite faultPolicy="ServiceExceptionFaults"/>-->
    <!--<composite faultPolicy="GenericSystemFaults"/>-->
</faultPolicyBindings>

12.4.1.4 Additional Fault Policy and Fault Policy Binding File Samples

This section provides additional samples of fault policy and fault policy binding files. Example 12-7 shows the fault-policies.xml file contents.

Example 12-7 fault-policies.xml File

<?xml version="1.0" encoding="UTF-8"?>
<faultPolicies xmlns="http://schemas.oracle.com/bpel/faultpolicy">
<faultPolicy version="2.0.1" 
                   id="CRM_ServiceFaults" 
                   xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" 
                   xmlns:xs="http://www.w3.org/2001/XMLSchema"
                   xmlns="http://schemas.oracle.com/bpel/faultpolicy" 
                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
                       <Conditions>
        <!-- Fault if wsdlRuntimeLocation is not reachable -->
        <faultName xmlns:bpelx="http://schemas.oracle.com/bpel/extension"
 name="bpelx:remoteFault">
            <condition>
                <test>$fault.code="WSDLReadingError"</test>
                <action ref="ora-terminate"/>
            </condition>
            <condition>
                <action ref="ora-java"/>
            </condition>
        </faultName>
        <!-- Fault if location port is not reachable-->
        <faultName xmlns:bpelx="http://schemas.oracle.com/bpel/extension"
 name="bpelx:bindingFault">
            <!--ORA-00001: unique constraint violated on insert-->
            <condition>
                <test>$fault.code="1"</test>
                <action ref="ora-java"/>
            </condition>
            <!--ORA-01400: cannot insert NULL -->
            <condition>
                <test xmlns:test="http://test">$fault.code="1400"</test>
                <action ref="ora-terminate"/>
            </condition>
            <!--ORA-03220: required parameter is NULL or missing -->
            <condition>
                <test>$fault.code="3220"</test>
                <action ref="ora-terminate"/>
            </condition>
            <condition>
                <action ref="ora-retry-crm-endpoint"/>
            </condition>
        </faultName>
        <!-- Business faults -->
        <!-- Fault comes with a payload of error, make sure the name space is
 provided here or at root level -->
        <faultName xmlns:credit="http://services.otn.com"
 name="credit:NegativeCredit">
            <!-- we get this fault when SSN starts with 0-->
            <condition>
                <test>$fault.payload="Bankruptcy Report"</test>
                <action ref="ora-human-intervention"/>
                <!--action ref="ora-retry"/-->
            </condition>
            <!-- we get this fault when SSN starts with 1-->
            <condition>
                <test>$fault.payload="Bankruptcy Report-abort"</test>
                <action ref="ora-terminate"/>
            </condition>
            <!-- we get this fault when SSN starts with 2-->
            <condition>
                <test>$fault.payload="Bankruptcy Report-rethrow"</test>
                <action ref="ora-rethrow-fault"/>
            </condition>
            <!-- we get this fault when SSN starts with 3-->
            <condition>
                <test>$fault.payload="Bankruptcy Report-replay"</test>
                <action ref="ora-replay-scope"/>
            </condition>
            <!-- we get this fault when SSN starts with 4-->
            <condition>
                <test
 xmlns:myError="http://services.otn.com">$fault.payload="Bankruptcy
 Report-human"</test>
                <action ref="ora-human-intervention"/>
            </condition>
            <!-- we get this fault when SSN starts with 5-->
            <condition>
                <test>$fault.payload="Bankruptcy Report-java"</test>
                <action ref="ora-java"/>
            </condition>
        </faultName>
                       
                       </Conditions>
                       <Actions>
                           <Action id="ora-retry">
            <retry>
                <retryCount>3</retryCount>
                <retryInterval>2</retryInterval>
                <exponentialBackoff/>
                <retryFailureAction ref="ora-java"/>
                <retrySuccessAction ref="ora-java"/>
            </retry>
        </Action>
        <Action id="ora-retry-crm-endpoint">
            <retry>
                <retryCount>5</retryCount>
                <retryFailureAction ref="ora-java"/>
                <retryInterval>5</retryInterval>
                <retrySuccessAction ref="ora-java"/>
            </retry>
        </Action>
        <Action id="ora-replay-scope">
            <replayScope/>
        </Action>
        <Action id="ora-rethrow-fault">
            <rethrowFault/>
        </Action>
        <Action id="ora-human-intervention">
            <humanIntervention/>
        </Action>
        <Action id="ora-terminate">
            <abort/>
        </Action>
        <Action id="ora-java">
            <!-- this is user provided class-->
            <javaAction
 className="com.oracle.bpel.client.config.faultpolicy.TestJavaAction"
 defaultAction="ora-terminate" propertySet="prop-for-billing">
                <returnValue value="REPLAY" ref="ora-terminate"/>
                <returnValue value="RETRHOW" ref="ora-rethrow-fault"/>
                <returnValue value="ABORT" ref="ora-terminate"/>
                <returnValue value="RETRY" ref="ora-retry"/>
                <returnValue value="MANUAL" ref="ora-human-intervention"/>
            </javaAction>
        </Action>
                       
                       </Actions>
                   <Properties>
                           <propertySet name="prop-for-billing">
            <property name="user_email_recipient">bpeladmin</property>
            <property name="email_recipient">joe@abc.com</property>
            <property name="email_recipient">mike@xyz.com</property>
            <property name="email_threshold">10</property>
            <property name="sms_recipient">+429876547</property>
            <property name="sms_recipient">+4212345</property>
            <property name="sms_threshold">20</property>
            <property name="user_email_recipient">john</property>
        </propertySet>
        <propertySet name="prop-for-order">
            <property name="email_recipient">john@abc.com</property>
            <property name="email_recipient">jill@xyz.com</property>
            <property name="email_threshold">10</property>
            <property name="sms_recipient">+42222</property>
            <property name="sms_recipient">+423335</property>
            <property name="sms_threshold">20</property>
        </propertySet>
                   
                   </Properties>                   
</faultPolicy>
<faultPolicy version="2.0.1" 
                   id="Billing_ServiceFaults" 
                   xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" 
                   xmlns:xs="http://www.w3.org/2001/XMLSchema"
        
                   xmlns="http://schemas.oracle.com/bpel/faultpolicy" 
                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<Conditions>
    <faultName>
    <condition>
       <action ref="ora-manual"/>
    </condition>
    </faultName>
</Conditions>
<Actions>
        <Action id="ora-manual">
            <humanIntervention/>
        </Action>
</Actions>
</faultPolicy>
</faultPolicies>

Example 12-8 shows the fault-buildings.xml file that associates the fault policies defined in fault-policies.xml.

Example 12-8 Fault Policy Bindings File

<?xml version="1.0" encoding="UTF-8"?>
<faultPolicyBindings version="2.0.1"
 xmlns="http://schemas.oracle.com/bpel/faultpolicy"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <composite faultPolicy="ConnectionFaults"/>
    <component faultPolicy="ServiceFaults">
        <name>Component1</name>
        <name>Component2</name>
    </component>
    <!-- Below listed component names use polic CRM_SeriveFaults --> 
    <component faultPolicy="CRM_ServiceFaults">
        <name>HelloWorld</name>
        <name>ShippingComponent</name>
        <name>AnotherComponent"</name>
    </component>
    <!-- Below listed reference names and port types use polic CRM_ServiceFaults
 --> 
    <reference faultPolicy="CRM_ServiceFaults">
        <name>creditRatingService</name>
        <name>anotherReference</name>
        <portType
 xmlns:credit="http://services.otn.com">credit:CreditRatingService</portType>
        <portType
 xmlns:db="http://xmlns.oracle.com/pcbpel/adapter/db/insert/">db:insert_
plt</portType>
    </reference>
    <reference faultPolicy="test1">
        <name>CreditRating3</name>
    </reference>
</faultPolicyBindings>

12.4.1.5 Designing a Fault Policy with Multiple Rejection Handlers

If you design a fault policy that uses the action handler for rejected messages, note that only one write action can be performed. Multiple write actions cannot be performed, even if you define multiple rejection handlers, as shown in Example 12-9. In this case, only the first rejection handler defined (for this example, ora-queue) is executed.

Example 12-9 Fault Policy with Multiple Rejection Handlers

<faultName xmlns:rjm="http://schemas.oracle.com/sca/rejectedmessages" 
name="rjm:FileIn"> 
        <condition> 
           <action ref="ora-queue"/> 
           
        </condition> 
       </faultName> 
        <faultName xmlns:rjm="http://schemas.oracle.com/sca/rejectedmessages" 
name="rjm:FileIn"> 
        <condition> 
           <action ref="ora-file"/> 
           
        </condition> 
       </faultName>

12.4.2 How to Execute a Fault Policy

You deploy a fault policy as part of a SOA composite application. After deployment, you can perform the following fault recovery actions from Oracle Enterprise Manager Fusion Middleware Control Console:

  • Retry the activity

  • Modify a variable (available to the faulted activity)

  • Continue the instance (mark the activity as a success)

  • Rethrow the exception

  • Abort the instance

  • Throw a replay scope exception

For additional information, see Oracle Fusion Middleware Administrator's Guide for Oracle SOA Suite for the following:

  • Instructions on executing a fault policy in Oracle Enterprise Manager Fusion Middleware Control Console

  • Use cases in which you define a fault policy that uses human intervention

12.4.3 How to Use a Java Action Fault Policy

Note the following details when using the Java action fault policy:

  • The Java class provided follows a specific interface. This interface returns a string. Multiple values can be provided for output and fault policy to take after execution.

  • Additional fault policy can be executed by providing a mapping from the output value (return value) of implemented methods to a fault policy.

  • If no ReturnValue is specified, the default fault policy is executed, as shown in Example 12-10.

Example 12-10 Java Action Fault Policy

<Action id="ora-java">
  <JavaAction ClassName="mypackage.myclass"
    defaultAction="ora-human-intervention" propertySet="prop-for-billing">
   <!--defaultAction is a required attribute, but propertySet is optional-->
   <!-- attribute-->
     <ReturnValue value="RETRY" ref="ora-retry"/>   
     <!--value is not nilable attribute & cannot be empty-->
     <ReturnValue value="RETRHOW" ref="ora-rethrow-fault"/>
  </JavaAction>
</Action>

Table 12-3 provides an example of ReturnValue use.

Table 12-3 System Interpretation of Java Action Fault Policy

Code Description 
<ReturnValue value="RETRY"
 ref="ora-retry"/>

Execute the ora-retry action if the method returns a string of RETRY.

 
<ReturnValue value="”
  ref=”ora-rethrow”/>

Fails in validation.

 
<JavaAction
 ClassName="mypackage.myclass"
 defaultAction="ora-human-intervention">

Execute ora-human-intervention after Java code execution. This attribute is used if the return from the method does not match any provided ReturnValue.

 
<ReturnValue value="RETRY"
 ref="ora-retry"/>
<ReturnValue value="” ref=””/>

Fails in validation.

 
<JavaAction
 ClassName="mypackage.myclass"
 defaultAction=" ora-human-intervention">
<ReturnValue></ReturnValue>

Fails in validation.

To invoke a Java class, you can provide a class that implements the IFaultRecoveryJavaClass interface. This interface has two methods, as shown in Example 12-11.

Example 12-11 implementation of IFaultRecoveryJavaClass

public interface IFaultRecoveryJavaClass
{
public void handleRetrySuccess( IFaultRecoveryContext ctx );
public String handleFault( IFaultRecoveryContext ctx );
}

Note the following details:

  • handleRetrySuccess is invoked upon a successful retry attempt. The retry policy chains to a Java action on retrySuccessAction.

  • handleFault is invoked to execute a policy of type javaAction.

Example 12-12 shows the data available with IFaultRecoveryContext:

Example 12-12 Data Available with IFaultRecoveryContext

public interface IFaultRecoveryContext {

/**
 * Gets implementation type of the fault.
 * @return
 */
public String getType();

/**
 * @return Get property set of the fault policy action being executed.
 */
public Map getProperties();

/**
 * @return Get fault policy id of the fault policy being executed.
 */
public String getPolicyId();

/**
 * @return Name of the faulted partner link.
 */
public String getReferenceName();

/**
 * @return Port type of the faulted reference .
 */
public QName getPortType();
}

The service engine implementation of this interface provides more information (for example, Oracle BPEL Process Manager). Example 12-13 provides details.

Example 12-13 Service Engine Implementation of IFaultRecoveryContext

public class BPELFaultRecoveryContextImpl extends BPELXExecLetUtil implements
IBPELFaultRecoveryContext,  IFaultRecoveryContext{
...
}

Oracle BPEL Process Manager-specific data is available with IBPELFaultRecoveryContext, as shown in Example 12-14.

Example 12-14 Oracle BPEL Process Manager-Specific Data

public interface IBPELFaultRecoveryContext {
public void addAuditTrailEntry(String message);

public void addAuditTrailEntry(String message, Object detail);

public void addAuditTrailEntry(Throwable t);
/**
 * @return Get action id of the fault policy action being executed.
 */
public String getActionId();

/**
 * @return Type of the faulted activity.
 */
public String getActivityId();

/**
 * @return Name of the faulted activity.
 */
public String getActivityName();

/**
 * @return Type of the faulted activity.
 */
public String getActivityType();

/**
 * @return Correleation id of the faulted activity.
 */
public String getCorrelationId();

/**
 * @return BPEL fault that caused the invoke to fault.
 */
public BPELFault getFault();

/**
 * @return Get index value of the instance
 */
public String getIndex(int i);

/**
 * @return get Instance Id of the current process instance of the faulted
 *         activity.
 */
public long getInstanceId();

/**
 * @return Get priority of the current process instance of the faulted
 *         activity.
 */
public int getPriority();

/**
 * @return Process DN.
 */
public ComponentDN getProcessDN();

/**
 * @return Get status of the current process instance of the faulted
 *         activity.
 */
public String getStatus();

/**
 * @return Get title of the current process instance of the faulted
 *         activity.
 */
public String getTitle();

public Object getVariableData(String name) throws BPELFault;

public Object getVariableData(String name, String partOrQuery)
throws BPELFault;

public Object getVariableData(String name, String part, String query)
throws BPELFault;

/**
 * @param priority
 *            Set priority of the current process instance of the faulted
 *            activity.
 * @return
 */
public void setPriority(int priority);

/**
 * @param status
 *            Set status of the current process instance of the faulted
 *            activity.
 */
public void setStatus(String status);

/**
 * @param title
 *            Set title of the current process instance of the faulted
 *            activity.
 * @return
 */
public String setTitle(String title);

public void setVariableData(String name, Object value) throws BPELFault;

public void setVariableData(String name, String partOrQuery, Object value)
throws BPELFault;

public void setVariableData(String name, String part, String query,
Object value) throws BPELFault;
}

Example 12-15 provides an example of javaAction implementation.

Example 12-15 Implementation of a javaAction

public class TestJavaAction implements IFaultRecoveryJavaClass {
public void handleRetrySuccess(IFaultRecoveryContext ctx) {
System.out.println("This is for retry success");
handleFault(ctx);
}
public String handleFault(IFaultRecoveryContext ctx) {           
System.out.println("-----Inside handleFault-----\n" + ctx.toString());

                dumpProperties(ctx.getProperties());
/* Get BPEL specific context here */
BPELFaultRecoveryContextImpl bpelCtx = (BPELFaultRecoveryContextImpl) ctx;
bpelCtx.addAuditTrailEntry("hi there");
System.out.println("Policy Id" + ctx.getPolicyId());
         ...
        }

12.4.4 What You May Need to Know About Fault Management Behavior When the Number of Instance Retries is Exceeded

When you configure a fault policy to recover instances with the ora-retry action and the number of specified instance retries is exceeded, the instance is marked as open.faulted (in-flight state). The instance remains active.

Marking instances as open.faulted ensures that no instances are lost. You can then configure another fault handling action following the ora-retry action in the fault policy file, such as the following:

  • Configure an ora-human-intervention action to manually perform instance recovery from Oracle Enterprise Manager Fusion Middleware Control Console.

  • Configure an ora-terminate action to close the instance (mark it as closed.faulted) and never retry again.

However, if you do not set an action to be performed after an ora-retry action in the fault policy file and the number of instance retries is exceeded, the instance remains marked as open.faulted, and recovery attempts to handle the instance.

For example, if no action is defined in the following fault policy file after ora-retry:

<Action id="ora-retry">
       <retry>
          <retryCount>2</retryCount>
          <retryInterval>2</retryInterval>
          <exponentialBackoff/>
       </retry>
  </Action>

The following actions are performed:

  • The invoke activity is attempted (using the above-mentioned fault policy code to handle the fault).

  • Two retries are attempted at increasing intervals (after two seconds, then after four seconds).

  • If all retry attempts fail, the following actions are performed:

    • A detailed fault error message is logged in the audit trail

    • The instance is marked as open.faulted (in-flight state)

    • The instance is picked up and the invoke activity is re-attempted

  • Recovery may also fail. In that case, the invoke activity is re-executed. Additional audit messages are logged.

12.4.5 What You May Need to Know About Binding Level Retry Execution Within Fault Policy Retries

If you are testing retry actions on adapters with both JCA-level retries for the outbound direction and a retry action in the fault policy file for outbound failures, the JCA-level (or binding level) retries are executed within the fault policy retries. For example, assume you have designed the application shown in Figure 12-2:

Figure 12-2 SOA Composite Application

Description of Figure 12-2 follows
Description of "Figure 12-2 SOA Composite Application"

You specify the following retry parameters in the composite.xml file:

<property name="jca.retry.count" type="xs:int" many="false"
  override="may">2</property>
<property name="jca.retry.interval" type="xs:int" many="false"
  override="may">2</property>
<property name="jca.retry.backoff" type="xs:int" many="false"
  override="may">2</property>

In the fault policy file for the EQ reference binding component for the outbound direction, you specify the following actions:

<retryCount>3</retryCount>
<retryInterval>3</retryInterval>

If an outbound failure occurs, the expected behavior is for the JCA retries to occur within the fault policy retries. When the first retry of the fault policy is executed, the JCA retry is called. In this example, a JCA retry of 2 with an interval of 2 seconds and exponential back off of 2 is executed for every retry of the fault policy:

  • Fault policy retry 1:

    • JCA retry 1 (with 2 seconds interval)

    • JCA retry 2 (with 4 seconds interval)

  • Fault policy retry 2:

    • JCA retry 1 (with 2 seconds interval)

    • JCA retry 2 (with 4 seconds interval)

  • Fault policy retry 3:

    • JCA retry 1 (with 2 seconds interval)

    • JCA retry 2 (with 4 seconds interval)

12.5 Catching BPEL Runtime Faults

BPEL runtime faults can be caught as a named BPEL fault. The bindingFault and remoteFault can be associated with a message. This action enables the faultHandler to get details about the faults.

12.5.1 How to Catch BPEL Runtime Faults

The following procedure shows how to use the provided examples to generate a fault and define a fault handler to catch it. In this case, you modify a WSDL file to generate a fault, and create a catch attribute to catch it.

To catch BPEL runtime faults:

  1. Import RuntimeFault.wsdl into your process WSDL. RuntimeFault.wsdl is seeded into the MDS from soa.mar inside soa-infra-wls.ear during its deployment.You may see a copy of soa.mar in the deployed SOA Infrastructure in the Oracle WebLogic Server domain, which is a JAR/ZIP file containing RuntimeFault.wsdl.

  2. Declare a variable with messageType bpelx:RuntimeFaultMessage.

  3. Catch it using the following syntax:

     <catch faultName="bpelx:remoteFault"  | "bpelx:bindingFault" faultName="varName">

12.6 Getting Fault Details with the getFaultAsString XPath Extension Function

The catchAll activity is provided to catch possible faults. However, BPEL does not provide a method for obtaining additional information about the captured fault. Use the getFaultAsString() XPath extension function to obtain additional information.

12.6.1 How to Get Fault Details with the getFaultAsString XPath Extension Function

Example 12-16 shows how to use this function.

Example 12-16 getFaultAsString() XPath Extension Function

<catchAll>
   <sequence>
      <assign>
         <from expression="bpelx:getFaultAsString()"/>
         <to variable="faultVar" part="message"/>
      </assign>
      <reply faultName="ns1:myFault" variable="faultVar" .../>
   </sequence>
</catchAll>

12.7 Throwing Internal Faults

A BPEL application can generate and receive fault messages. The throw activity has three elements: its name, the name of the fault, and the fault variable. If you add a throw activity to your BPEL process service component, it automatically includes a copy rule that copies the fault name and type into the output payload. The fault thrown by a throw activity is internal to BPEL. You cannot use a throw activity on an asynchronous process to communicate with a client.

12.7.1 How to Create a Throw Activity

To create a throw activity:

  1. From the Component Palette, drag a Throw activity into the designer.

  2. Double-click and define the Throw activity.

  3. Optionally enter a name or accept the default value.

  4. To the right of the Namespace URI field, click the Search icon to select the fault to monitor.

  5. Select the fault in the Fault Chooser dialog, and click OK.

    The namespace URI for the selected fault displays in the Namespace URI field. Your fault selection also automatically displays in the Local Part field.

    Figure 12-3 provides an example of a completed Throw dialog. This example shows the Throw_Fault_CC_Denied throw activity of the Scope_AuthorizeCreditCard scope activity in the WebLogic Fusion Order Demo application. This activity throws a fault for orders that are not approved.

    Figure 12-3 Throw Dialog

    Description of Figure 12-3 follows
    Description of "Figure 12-3 Throw Dialog"

  6. Click OK.

12.7.2 What Happens When You Create a Throw Activity

Example 12-17 shows the throw activity in the .bpel file after design completion. The OrderProcessor process terminates after executing this throw activity.

Example 12-17 Throw Activity

<throw name="Throw_Fault_CC_Denied"
    faultName="client:OrderProcessorFault"/>

12.8 Returning External Faults

A BPEL process service component can send a fault to another application to indicate a problem, as opposed to throwing an internal fault. In a synchronous operation, the reply activity can return the fault. In an asynchronous operation, the invoke activity performs this function.

12.8.1 How to Return a Fault in a Synchronous Interaction

The syntax of a reply activity that returns a fault in a synchronous interaction is shown in Example 12-18:

Example 12-18 Reply Activity

<reply partnerlinke="partner-link-name"
       portType="port-type-name"
       operation="operation-name"
       variable="variable-name" (optional)
       faultName="fault-name">
</reply>

Always returning a fault in response to a synchronous request is not very useful. It is better to make the activity part of a conditional branch, in which the first branch is executed if the data requested is available. If the requested data is not available, then the BPEL process service component returns a fault with this information.

For more information, see the following chapters:

12.8.2 How to Return a Fault in an Asynchronous Interaction

In an asynchronous interaction, the client does not wait for a reply. The reply activity is not used to return a fault. Instead, the BPEL process service component returns a fault using a callback operation on the same port type that normally receives the requested information, with an invoke activity.

For more information about asynchronous interactions, see Chapter 9, "Invoking an Asynchronous Web Service from a BPEL Process."

12.9 Using a Scope Activity to Manage a Group of Activities

A scope activity provides a container and a context for other activities. A scope provides handlers for faults, events, compensation, data variables, and correlation sets. Using a scope activity simplifies a BPEL flow by grouping functional structures. This grouping allows you to collapse them into what appears to be a single element in Oracle BPEL Designer.

Example 12-19 shows a scope named Scope_FulfillOrder from the WebLogic Fusion Order Demo application. This scope invokes the FulfillOrder mediator component, which determines the shipping method for the order.

Example 12-19 Scope Activity

<scope name="Scope_FulfillOrder">
    <variables>
        <variable name="lFulfillOrder_InputVariable"
        messageType="ns17:requestMessage"/>
    </variables>
    <sequence>
        <assign name="Assign_OrderData">
            <copy>
                <from variable="gOrderInfoVariable"
                    query="/ns4:orderInfoVOSDO"/>
                <to variable="lFulfillOrder_InputVariable"
                    part="request" query="/ns4:orderInfoVOSDO"/>
            </copy>
        </assign>
        <invoke name="Invoke_FulfillOrder"
            inputVariable="lFulfillOrder_InputVariable"
            partnerLink="FulfillOrder.FulfillOrder"
            portType="ns17:execute_ptt" operation="execute"/>
    </sequence>
</scope>

12.9.1 How to Create a Scope Activity

To create a scope activity:

  1. From the Component Palette, drag a Scope activity into the designer.

  2. Open the scope activity by double-clicking it or by single-clicking the Expand icon.

  3. From the Component Palette, drag and define activities to build the functionality within the scope.

    Figure 12-4 Expanded Scope Activity

    Description of Figure 12-4 follows
    Description of "Figure 12-4 Expanded Scope Activity"

  4. Click OK.

    When complete, scope activity design can look as shown in . This example shows the Scope_AuthorizeCreditCard scope activity of the WebLogic Fusion Order Demo application.

    Figure 12-5 Scope Activity After Design Completion

    Description of Figure 12-5 follows
    Description of "Figure 12-5 Scope Activity After Design Completion"

12.9.2 What Happens After You Create a Scope Activity

Example 12-20 shows the throw activity in the .bpel file after design completion. The Scope_AuthorizeCreditCard scope activity consists of activities that perform the following actions:

  • A catch activity for catching faulted orders in which the credit card number is not provided or the credit type is not valid.

  • A throw activity that throws a fault for orders that are not approved.

  • An assign activity that takes the credit card type, credit card number, and purchase amount, and assigns it to the input variable for the CreditCardAuthorizationService service.

  • An invoke activity that calls a CreditCardAuthorizationService service to retrieve customer information.

  • A switch activity that checks the results of the credit card validation.

Example 12-20 Scope Activity

<scope name="Scope_AuthorizeCreditCard">
    <variables>
        <variable name="lCreditCardInput"
            messageType="ns2:CreditAuthorizationRequestMessage"/>
        <variable name="lCreditCardOutput"
            messageType="ns2:CreditAuthorizationResponseMessage"/>
    </variables>
    <faultHandlers>
        <catch faultName="bpws:selectionFailure">
            <sequence>
                 <assign name="Assign_noCCNumber">
                     <copy>
                         <from expression="string('CreditCardCheck - NO
                             CreditCard')"/>
                         <to variable="gOrderProcessorFaultVariable"
                             part="code"/>
                     </copy>
                 </assign>
                 <throw name ="Throw_NoCreditCard"
                     faultVariable="gOrderProcessorFaultVariable"
                     faultName="ns9:OrderProcessingFault"/>
            </sequence>
        </catch>
        <catch faultName="ns2:InvalidCredit">
            <sequence>
                <assign name="Assign_InvalidCreditFault">
                    <copy>
                        <from expression="concat(bpws:getVariableData
                             ('gOrderInfoVariable','/ns4:orderInfoVOSDO/
                             ns4:CardTypeCode'), ' is not a valid 
                             creditcard type')"/>
                        <to variable="gOrderProcessorFaultVariable"
                            part="summary"/>
                    </copy>
                    <copy>
                        <from expression="string('CreditCardCheck - NOT VALID')"/>
                        <to variable="gOrderProcessorFaultVariable"
                            part="code"/>
                    </copy>
                </assign>
                <throw name="Throw_OrderProcessingFault"
                    faultName="ns9:OrderProcessingFault"
                    faultVariable="gOrderProcessorFaultVariable"/>
            </sequence>
        </catch>
    </faultHandlers>
    <sequence>
        <assign name="Assign_CreditCheckInput">
            <copy>
                <from variable="gOrderInfoVariable"
                    query="/ns4:orderInfoVOSDO/ns4:OrderTotal"/>
                <to variable="lCreditCardInput" part="Authorization"
                    query="/ns8:AuthInformation/ns8:PurchaseAmount"/>
            </copy>
            <copy>
                <from variable="gOrderInfoVariable"
                    query="/ns4:orderInfoVOSDO/ns4:CardTypeCode"/>
                        <to variable="lCreditCardInput" part="Authorization"
                             query="/ns8:AuthInformation/ns8:CCType"/>
            </copy>
            <copy>
                <from variable="gOrderInfoVariable"
                    query="/ns4:orderInfoVOSDO/ns4:AccountNumber"/>
                <to variable="lCreditCardInput" part="Authorization"
                    query="/ns8:AuthInformation/ns8:CCNumber"/>
                    </copy>
        </assign>
        <invoke name="InvokeCheckCreditCard"
            inputVariable="lCreditCardInput"
            outputVariable="lCreditCardOutput"
            partnerLink="CreditCardAuthorizationService"
            portType="ns2:CreditAuthorizationPort"
            operation="AuthorizeCredit"/>
        <switch name="Switch_EvaluateCCResult">
            <case condition="bpws:getVariableData('lCreditCardOutput','status','
                /ns8:status') != 'APPROVED'">
                <bpelx:annotation>
                    <bpelx:pattern>status &lt;&gt; approved</bpelx:pattern>
                </bpelx:annotation>
                <throw name="Throw_Fault_CC_Denied"
                    faultName="client:OrderProcessorFault"/>
            </case>
        /switch>
    </sequence>
</scope>

12.9.3 What You May Need to Know About Scopes

Scopes can use a significant amount of CPU and memory and should not be overused. Sequence activities use less CPU and memory and can be used to make large BPEL flows more readable.

12.9.4 How to Use a Fault Handler within a Scope

If a fault is not handled, it creates a faulted state that migrates up through the application and can throw the entire process into a faulted state. To prevent this, contain the parts of the process that have the potential to receive faults within a scope. The scope activity includes the following fault handling capabilities:

  • The catch activity works within a scope to catch faults and exceptions before they can throw the entire process into a faulted state. You can use specific fault names in the catch activity to respond in a specific way to an individual fault.

  • The catchAll activity catches any faults that are not handled by name-specific catch activities.

Example 12-21 shows the syntax for catch and catch all activities. Assume that a fault named x:foo is thrown. The first catch is selected if the fault carries no fault data. If there is fault data associated with the fault, the third catch is selected if the type of the fault's data matches the type of variable bar. Otherwise, the default catchAll handler is selected. Finally, a fault with a fault variable whose type matches the type of bar and whose name is not x:foo is processed by the second catch. All other faults are processed by the default catchAll handler.

Example 12-21 Catch and Catch All Activities

<faulthandlers>
   <catch faultName="x:foo">
         <empty/>
      </catch>
   <catch faultVariable="bar">
         <empty/>
      </catch>
   <catch faultName="x:foo" faultVariable="bar">
         <empty/>
      </catch>
   <catchAll>
         <empty/>
      </catchAll>
</faulthandlers>

12.9.5 How to Create a Catch Activity

To create a catch activity:

  1. In the expanded Scope activity, click Add Catch Branch.

    Figure 12-6 Add Catch Branch

    Description of Figure 12-6 follows
    Description of "Figure 12-6 Add Catch Branch"

    This creates a catch activity in the right side of the scope activity.

  2. Double-click the Catch activity.

  3. Optionally enter a name.

  4. To the right of the Namespace URI field, click the Search icon to select the fault.

  5. Select the fault in the Fault Chooser dialog, and click OK.

    The namespace URI for the selected fault displays in the Namespace URI field. Your fault selection also automatically displays in the Local Part field.

    Figure 12-7 provides an example of a Catch dialog. This example shows the selectionFailure catch activity of the Scope_AuthorizeCreditCard scope activity in the WebLogic Fusion Order Demo application. This catch activity catches orders in which the credit card number is not provided.

    Figure 12-7 Catch Dialog

    Description of Figure 12-7 follows
    Description of "Figure 12-7 Catch Dialog"

  6. Design additional fault handling functionality.

  7. Click OK.

    Figure 12-8 provides an example of two catch activities for the Scope_AuthorizeCreditCard scope activity. The second catch activity catches credit types that are not valid.

    Figure 12-8 Catch Activities in the Designer

    Description of Figure 12-8 follows
    Description of "Figure 12-8 Catch Activities in the Designer"

12.9.6 What Happens When You Create a Catch Branch

Figure 12-8 shows the catch activity in the .bpel file after design completion. The selectionFailure catch activity catches orders in which the credit card number is not provided and the InvalidCredit catch activity catches credit types that are not valid.

Example 12-22 Catch Branch

<faultHandlers>
    <catch faultName="bpws:selectionFailure">
        <sequence>
            <assign name="Assign_noCCNumber">
                <copy>
                    <from expression="string('CreditCardCheck - NO CreditCard')"/>
                    <to variable="gOrderProcessorFaultVariable"
                        part="code"/>
                </copy>
            </assign>
            <throw name ="Throw_NoCreditCard"
               faultVariable="gOrderProcessorFaultVariable"
               faultName="ns9:OrderProcessingFault"/>
    </sequence>
 </catch>
 <catch faultName="ns2:InvalidCredit">
    <sequence>
        <assign name="Assign_InvalidCreditFault">
           <copy>
              <from expression="concat(bpws:getVariableData
                 ('gOrderInfoVariable','/ns4:orderInfoVOSDO/ns4:CardTypeCode'), '
                 is not a valid creditcard type')"/>
              <to variable="gOrderProcessorFaultVariable"
                 part="summary"/>
           </copy>
           <copy>
               <from expression="string('CreditCardCheck - NOT VALID')"/>
               <to variable="gOrderProcessorFaultVariable"
                   part="code"/>
           </copy>
        </assign>
        <throw name="Throw_OrderProcessingFault"
           faultName="ns9:OrderProcessingFault"
           faultVariable="gOrderProcessorFaultVariable"/>
    </sequence>
  </catch>
</faultHandlers>

12.9.7 How to Create an Empty Activity to Insert No-Op Instructions into a Business Process

There is often a need to use an activity that does nothing. An example is when a fault must be caught and suppressed. In this case, you can use the empty activity to insert a no-op instruction into a business process.

To create an empty activity:

  1. From the Component Palette, drag an Empty activity into the designer.

  2. Double-click the Empty activity.

    The Empty dialog appears, as shown in Figure 12-9.

    Figure 12-9 Empty Activity

    Description of Figure 12-9 follows
    Description of "Figure 12-9 Empty Activity"

  3. Optionally enter a name.

  4. Click OK.

12.9.8 What Happens When You Create an Empty Activity

The syntax for an empty activity is shown in Example 12-23.

Example 12-23 Empty Activity

 <empty standard-attributes>
    standard-elements
  </empty>

If no catch or catchAll is selected, the fault is not caught by the current scope and is rethrown to the immediately enclosing scope. If the fault occurs in (or is rethrown to) the global process scope, and there is no matching fault handler for the fault at the global level, the process terminates abnormally. This is as though a terminate activity (described in Section 12.11, "Using the Terminate Activity to Stop a Business Process Instance") had been performed.

12.10 Using Compensation After Undoing a Series of Operations

Compensation occurs when the BPEL process service component cannot complete a series of operations after some have completed, and the BPEL process service component must backtrack and undo the previously completed transactions. For example, if a BPEL process service component is designed to book a rental car, a hotel, and a flight, it may book the car and the hotel and then be unable to book a flight for the right day. In this case, the BPEL flow performs compensation by going back and unbooking the car and the hotel.

12.10.1 How to Use Compensation After Undoing a Series of Operations

You can invoke a compensation handler by using the compensate activity, which names the scope for which the compensation is to be performed (that is, the scope whose compensation handler is to be invoked). A compensation handler for a scope is available for invocation only when the scope completes normally. Invoking a compensation handler that has not been installed is equivalent to using the empty activity (it is a no-op). This ensures that fault handlers do not have to rely on state to determine which nested scopes have completed successfully. The semantics of a process in which an installed compensation handler is invoked multiple times are undefined.

The ability to explicitly invoke the compensate activity is the underpinning of the application-controlled error-handling framework of Business Process Execution Language for Web Services Specification. You can use this activity only in the following parts of a business process:

  • In a fault handler of the scope that immediately encloses the scope for which compensation is to be performed.

  • In the compensation handler of the scope that immediately encloses the scope for which compensation is to be performed.

For example:

<compensate scope="RecordPayment"/>

If a scope being compensated by name was nested in a loop, the BPEL process service component invokes the instances of the compensation handlers in the successive iterations in reverse order.

If the compensation handler for a scope is absent, the default compensation handler invokes the compensation handlers for the immediately enclosed scopes in the reverse order of the completion of those scopes.

The compensate form, in which the scope name is omitted in a compensate activity, explicitly invokes this default behavior. This is useful when an enclosing fault or compensation handler must perform additional work, such as updating variables or sending external notifications, in addition to performing default compensation for inner scopes. The compensate activity in a fault or compensation handler attached to the outer scope invokes the default order of compensation handlers for completed scopes directly nested within the outer scope. You can mix this activity with any other user-specified behavior except for the explicit invocation of the nested scope within the outer scope. Explicitly invoking a compensation for such a scope nested within the outer scope disables the availability of default-order compensation.

12.10.2 How to Create a Compensate Activity

To create a compensate activity:

  1. From the Component Palette, drag an Compensate activity into the designer.

  2. Double-click the Compensate activity.

  3. Select a scope activity in which to invoke the compensation handler.

    Figure 12-10 Compensate Activity

    Description of Figure 12-10 follows
    Description of "Figure 12-10 Compensate Activity"

  4. Click OK.

12.10.3 What Happens When You Create a Compensate Activity

If an invoke activity has a compensation handler defined inline, then the name of the activity is the name of the scope to be used in the compensate activity. The syntax is shown in Example 12-24:

Example 12-24 Compensation Handler

<compensate scope="ncname"? standard-attributes>
    standard-elements
  </compensate>

12.11 Using the Terminate Activity to Stop a Business Process Instance

The terminate activity immediately terminates the behavior of a business process instance within which the terminate activity is performed. All currently running activities must be terminated as soon as possible without any fault handling or compensation behavior. The terminate activity does not send any notifications of the status of a BPEL process service component. If you are going to use the terminate activity, first program notifications to the interested parties.

12.11.1 How to Create a Terminate Activity

To create a terminate activity:

  1. From the Component Palette in Oracle JDeveloper, drag a Terminate activity into the designer. Figure 12-11 provides an example.

    Figure 12-11 Terminate Activity

    Description of Figure 12-11 follows
    Description of "Figure 12-11 Terminate Activity"

  2. Double-click the terminate activity.

  3. Optionally enter a name.

  4. Click OK.

12.11.2 What Happens When You Create a Terminate Activity

The syntax for the terminate activity is shown in Example 12-25. This stops the business process instance.

Example 12-25 Terminate Activity

<terminate standard-attributes>
    standard-elements
</terminate>