Flow and Web Services - Putting Together the Flow Sample

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Having said all that, let's get back to SkatesTown's flow as outlined in Figure 12.5. Listing 12.2 shows how this flow is expressed using the BPEL flow activity. The definition of a flow activity always starts with the specification of its links. Activities of a flow become the source and/or target of these links by referencing them via the standard activity elements source and target. The transition condition is an optional attribute of the activity's source element:

Listing 12.2 Flow Activity

<flow>
<links>
<link name="validPurchaseOrder"/>
<link name="invalidPurchaseOrder"/>
<link name="inLocalStock_initiateDelivery"/>
<link name="inLocalStock_createInvoice"/>
<link name="notInLocalStock"/>
<link name="stockReplenished_initiateDelivery"/> 
<link name="stockReplenished_createInvoice"/>
</links>
<invoke partnerLink="local"

portType="skt:skatestownPortType"
operation="validatePurchaseOrder" 
inputVariable="poSubmissionRequest"
outputVariable=

"validatePurchaseOrderResponse">
<source linkName="validPurchaseOrder"

transitionCondition=
"bpws:getVariableData

('validatePurchaseOrderResponse','valid')=true"/>
<source linkName="invalidPurchaseOrder"

transitionCondition=
"bpws:getVariableData

('validatePurchaseOrderResponse','valid')=false"/>
</invoke>
<throw faultName="pos:invalidPO">
<target linkName="invalidPurchaseOrder"/>
</throw>
<invoke partnerLink="local"

portType="skt:skatestownPortType"
operation="checkLocalStock" 
inputVariable="poSubmissionRequest"
outputVariable="checkLocalStockResponse">
<target linkName="validPurchaseOrder"/>
<source linkName="inLocalStock_createInvoice"

transitionCondition=
"bpws:getVariableData

('checkLocalStockResponse','available')=true"/>
<source

linkName="inLocalStock_initiateDelivery"

transitionCondition=
"bpws:getVariableData

('checkLocalStockResponse','available')=true"/>
<source linkName="notInLocalStock"

transitionCondition=
"bpws:getVariableData

('checkLocalStockResponse','available')=false"/>
</invoke>  
<sequence name="replenishStock">
<target linkName="notInLocalStock"/>
<source

linkName="stockReplenished_initiateDelivery"/>
<source

linkName="stockReplenished_createInvoice"/>
...
</sequence>
<invoke partnerLink="local"

portType="skt:skatestownPortType"
operation="initiateDelivery" 
inputVariable="poSubmissionRequest">
<target

linkName="inLocalStock_initiateDelivery"/>
<target

linkName="stockReplenished_initiateDelivery"/>
</invoke>
<invoke partnerLink="local"

portType="skt:skatestownPortType"
operation="createInvoice" 
inputVariable="poSubmissionRequest" 
outputVariable="poSubmissionResponse">
<target linkName="inLocalStock_createInvoice"/>
<target

linkName="stockReplenished_createInvoice"/>
</invoke>
</flow>

Please check back next week for the continuation of this article.

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