Hi, Thank you for your explanation.
Bill McCusker wrote: > > Hi, > > Variables need to be initialized before they are assigned from or when > assigned to using a query or an expression or if they are used as to > input to an invoke or in conditional expressions. If you are just > assigning directly to a variable's message part with no query then no > initialization is needed. Thats why the second example needs no > initialization. > > Bill McCusker > > phanlesang wrote: >> Hi Everyone! >> I'm getting confused about when we need to initialize a variable in BPEL >> 2.0 >> though BPEL 2.0 standard says that every variable must be initialized >> before >> using. >> For example: >> In the HelloBPELProcess example, I see the variable output is >> initialized: >> >> <bpel:assign validate="no" name="createResponse"> >> <bpel:copy> >> <bpel:from> >> <bpel:literal >> xml:space="preserve"><tns:HelloBPELProcessResponse >> xmlns:tns="http://www.se.uni-hannover.de/soa08/tutorial/HelloBPELProcess"; >> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";> >> <tns:result></tns:result> >> </tns:HelloBPELProcessResponse> >> </bpel:literal> >> </bpel:from> >> <bpel:to variable="output" part="payload"></bpel:to> >> </bpel:copy> >> <bpel:copy> >> <bpel:from part="payload" variable="input"> >> <bpel:query >> queryLanguage="urn:oasis:names:tc:wsbpel:2.0:sublang:xpath1.0"><![CDATA[tns:input]]></bpel:query> >> </bpel:from> >> <bpel:to part="payload" variable="output"> >> <bpel:query >> queryLanguage="urn:oasis:names:tc:wsbpel:2.0:sublang:xpath1.0"><![CDATA[tns:result]]></bpel:query> >> </bpel:to> >> </bpel:copy> >> </bpel:assign> >> >> But in the SimpleInvokeProcess process, the variable output is not >> initialized: >> >> <bpel:assign validate="no" name="PrepareRandomHelloRequest"> >> <bpel:copy> >> <bpel:from> >> <bpel:literal xml:space="preserve"><impl:sayHello >> xmlns:impl="http://randomHelloService.tutorial.soa08.se.unihannover.de"; >> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";> >> <impl:withSpace></impl:withSpace> >> </impl:sayHello> >> </bpel:literal> >> </bpel:from> >> <bpel:to variable="RandomHelloRequest" >> part="parameters"></bpel:to> >> </bpel:copy> >> <bpel:copy> >> <bpel:from> >> <bpel:literal >> xml:space="preserve">true</bpel:literal> >> </bpel:from> >> <bpel:to part="parameters" variable="RandomHelloRequest"> >> <bpel:query >> queryLanguage="urn:oasis:names:tc:wsbpel:2.0:sublang:xpath1.0"><![CDATA[ns1:withSpace]]></bpel:query> >> </bpel:to> >> </bpel:copy> >> </bpel:assign> >> <bpel:invoke name="GetGreeting" partnerLink="RandomHelloPL" >> operation="sayHello" portType="ns1:RandomHelloService" >> inputVariable="RandomHelloRequest" >> outputVariable="RandomHelloResponse"></bpel:invoke> >> <bpel:assign validate="no" name="PrepareOutput"> >> <bpel:copy> >> <bpel:from xmlns:http="urn:http:namesapce"> >> >> <![CDATA[concat(bpel:getVariableData('RandomHelloResponse', 'parameters', >> '/'), bpel:getVariableData('input', 'payload', '/'))]]> >> </bpel:from> >> <bpel:to variable="output" part="payload"></bpel:to> >> </bpel:copy> >> </bpel:assign> >> >> Thanks for any help! >> >> ----- >> Sang PL http://www.nabble.com/file/u1501219/20.gif >> > > > ----- Sang PL -- View this message in context: http://www.nabble.com/When-we-need-to-initialize-a-variable-tp24403747p24410292.html Sent from the Apache Ode User mailing list archive at Nabble.com.
