Robust Workflow Systems Flexible Geoprocessing Services Geo-enabled Model Web? - Geographical Information Systems: Trends and Technologies - page 182

Fig. 3. Graphical representation of a WS-BPEL process.

01 <?xml version = “1.0” encoding = “UTF-8” ?>
02 <process name=“HolaMundo” targetNamespace=“http://xmlns.oracle.com/HolaMundo”
03 xmlns=“http://schemas.xmlsoap.org/ws/2003/03/business-process/”
04 xmlns:client=“http://xmlns.oracle.com/HolaMundo”>
05
06 <!-- PARTNERLINKS: List of services participating in this BPEL process -->
07 <partnerLinks>
08 <partnerLink name=“client” partnerLinkType=“client:HolaMundo”
09 myRole=“HolaMundoProvider”/>
10 </partnerLinks>
11
12 <!-- VARIABLES: List of messages and XML documents used within this BPEL process -->
13 <variables>
14 <variable name=“inputVariable”
15 messageType=“client:HolaMundoRequestMessage”/>
16 <variable name=“outputVariable”
17 messageType=“client:HolaMundoResponseMessage”/>
18 </variables>
19
20 <!-- ORCHESTRATION LOGIC: Set of activities coordinating the fl ow of messages across the
21 services integrated within this business process -->

22
23 <sequence name=“main”>
24 <receive name=“receiveInput” partnerLink=“client”
25 portType=“client:HolaMundo” operation=“process”
26 variable=“inputVariable” createInstance=“yes”/>
27 <reply name=“replyOutput” partnerLink=“client” portType=“client:HolaMundo”
28 operation=“process” variable=“outputVariable”/>
29 </sequence>
30 </process>

Fig. 4. XML description of the WS-BPEL process in Fig. 3.

WS-BPEL is supported by various workfl ow enactment engines either
commercial like ActiveVOS 15 or open source based implementations such
like Apache ODE. 16 Interested readers can fi nd more information on the
primer document 17 and in Vasiliev (2007).

15 http://activevos.com/products/activevos/overview
16 Apache ODE (Orchestration Director Engine), http://ode.apache.org/
17 http://docs.oasis-open.org/wsbpel/2.0/Primer/wsbpel-v2.0-Primer.htm