Invoke

• The <invoke> construct allows the business process to invoke a one-way or request-response operation on a portType offered by a partner.

<invoke partnerLink="ncname" portType="qname" operation="ncname"
        inputVariable="ncname"? outputVariable="ncname"?
        standard-attributes>
  standard-elements
  <correlations>?
     <correlation set="ncname" initiate="yes|no"? 
                  pattern="in|out|out-in"/>+
  </correlations>
  <catch faultName="qname" faultVariable="ncname"?>*
    activity
  </catch>
  <catchAll>?
    activity
  </catchAll>
  <compensationHandler>?
    activity
  </compensationHandler>
</invoke>

<!--- for example -->
<invoke partnerLink="Seller" portType="SP:Purchasing" 
        operation="SyncPurchase" 
        inputVariable="sendPO" 
        outputVariable="getResponse">
  <compensationHandler>
      <invoke partnerLink="Seller" portType="SP:Purchasing" 
              operation="CancelPurchase" 
              inputVariable="getResponse"
              outputVariable="getConfirmation">
  </compensationHandler>
</invoke>

• We are invoking a web service!