The code segment in the .bpel file defines the specific operation after design completion.

For example, the XPath expression shown in the following code, when evaluated to true (for example, input is 20), causes the assign activity to be skipped.

<sequence name="main">
. . .
. . .
<assign name="Assign_1"
                bpelx:skipCondition="number(bpws:getVariableData('inputVariable','payload','/client:
 process/client:input')) > 10">
    <copy>
       <from expression="'Assign Block is not Skipped'"/>
          <to variable="inputVariable" part="payload"
             query="/client:process/client:input"/>
    </copy>
</assign>
. . .
. . .
</sequence>

The bpelx:skipCondition attribute is equivalent to a switch/case structured activity with a single case element with a condition that is the opposite of the skip condition.

The following example shows the bpelx:skipCondition attribute in BPEL 1.1. If myvalue is 0, the expression evaluates to true, and the assign activity is skipped. If myvalue is 10, the expression evaluates to false, and the copy operation of the assign activity is executed.

<assign bpelx:skipCondition="bpws:getVariableData('input',
 'payload','/tns:inputMsg/tns:myvalue') <= 0">
    <copy>
        <from expression="'Value is greater than zero'"/>
        <to variable="output" part="payload"
 query="/tns:resultMsg/tns:valueResult"/>
    </copy>
</assign>

The equivalent functionality used with a switch activity is shown in the following example.

<switch>
    <case condition="bpws:getVariableData('input',
 'payload','/tns:inputMsg/tns:value') > 0">
        <assign>
            <copy>
                <from expression="'Value is greater than zero'"/>
                <to variable="output" part="payload"
 query="/tns:resultMsg/tns:valueResult"/>
            </copy>
        </assign>
    </case>
</switch>

In BPEL 2.0, the bpelx:skipCondition syntax appears as a child element of an activity. The following code provides an example of an assign activity with this convention.

<assign name="Assign4">
<bpelx:skipCondition>ora:getNodeValue($inputVariable.payload/client:input) > 5
</bpelx:skipCondition><copy>
            <from>"dummy result"</from>
            <to>$outputVariable.payload/client:result</to>
          </copy></assign>

You can also use built-in and custom XPath functions within the skip condition expression. The following code provides several examples.

<assign bpelx:skipCondition="bpws:getVariableData( 'crOutput', 'payload',
 '/tns:rating' ) > 0">

<assign bpelx:skipCondition="custom:validateRating()" ... />

<assign xmlns:fn='http://www.w3.org/2005/xpath-functions'
 bpelx:skipCondition="fn:false()" ... />

If an error is thrown by the XPath expression evaluation, the error is wrapped with a BPEL fault and thrown from the activity.

An event is added to the BPEL instance audit trail for activities that are bypassed due to the skip condition expression evaluating to true. Even if the skip condition evaluates to false (meaning the activity is performed), the fact that a skip condition expression was evaluated is still logged to the audit trail for debugging purposes.

If the XPath engine fails to evaluate the boolean value, bpws:subLanguageFault is thrown. This is the same fault thrown when a switch/case condition does not evaluate to a boolean value. This is also logged to the audit trail for debugging purposes.