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Subject: Re: AW: [wsbpel] Issue - 147 - Serial and Parallel For-Each
I also think that we should make it possible to directly edit the iterator variable itself. We would specify the iterator variable as effectively a pointer at the information item in the source variable. The programmer would then be able to edit that variable directly and thus change the source document. Alex Yiu wrote: > > > Hi, > > Regarding to Frank's question: "How is the output of the set of > activities running in parallel combined?": > > If I understand what he means correctly, he may mean how to aggregrate > individual data pieces received / generated by individual parallel flow > into one bigger data E.g. aggregating the results of different RFQ into > one business doc. In some cases, the order of aggregration / document > order matters. > > Potential answers are: [sorry ... kind of heading back to Issue 11 :-) ]. > (1) a sequential forEach to initialize a sequence of empty quotation in > a particular order. > e.g. <quotation supplier="..."> ...</quotation> > (2) The parallel forEach will assign the data to specified location by > looking up by supplier attribute: > <to ...$var/quotation[@supplier=$supplierVar] /> > > If the aggregration order does not matter, we don't need to intialize a > sequence. We just need to use "append" within the parallel forEach > (Issue 11 here again ...) > > > Thanks! > > > Regards, > Alex Yiu > > > Yaron Y. Goland wrote: > > > Please see below > > > > Frank Leymann wrote: > > > >> > >> > >> Yaron – initial questions: > >> > >> > >> > >> How is the output of the set of activities running in parallel > combined? > >> > > > > I'm not sure I understand what you mean. None of our activities have > > return values so what would we be combining? > > > >> > >> > >> What is the fault model, i.e. what happens if a subset of the forked > >> activities fail? > >> > > > > The parallel for-each is effectively a dynamic flow. The same fault > > and completion conditions that apply to flows also apply to parallel > > for-each. > > > >> > >> > >> > >> > >> Best regards, > >> > >> Frank Leymann > >> > >> Phone:......+49-711-7816 470 > >> > >> Mobile:.....+49-162-322 4444 > >> > >> e-Mail: Frank.Leymann@informatik.uni-stuttgart.de > >> > >> > >> > >> -----Ursprüngliche Nachricht----- > >> *Von:* ws-bpel issues list editor [mailto:peter.furniss@choreology.com] > >> *Gesendet:* Friday, July 16, 2004 3:10 PM > >> *An:* wsbpel@lists.oasis-open.org > >> *Betreff:* [wsbpel] Issue - 147 - Serial and Parallel For-Each > >> > >> > >> > >> This issue has been added to the wsbpel issue list. The issues list > >> is posted as a Technical Committee document to the OASIS WSBPEL TC > >> pages <http://www.oasis-open.org/apps/org/workgroup/wsbpel> on a > >> regular basis. The current edition, as a TC document, is the most > >> recent version of the document entitled in the "Issues" folder of the > >> WSBPEL TC document list > >> <http://www.oasis-open.org/apps/org/workgroup/wsbpel/documents.php> - > >> the next posting as a TC document will include this issue. The list > >> editor's working copy, which will normally include an issue when it > >> is announced, is available at this constant URL > >> <http://www.choreology.com/external/WS_BPEL_issues_list.html>. > >> > >> > >> * Issue - 147 - Serial and Parallel For-Each * > >> > >> * Status: * open > >> *Categories:* Syntax and validation <#category_syntax_and_validation> > >> *Date added:* 16 Jul 2004 > >> *Submitter:* Yaron Y. Goland <mailto:ygoland@bea.com> > >> *Date submitted:* 15 June 2004 > >> *Description:* For-each is a very common control structure that has > >> special appropriateness to BPEL where one can routinely expect BPELs > >> to need to iterate through XML structures. One can easily imagine two > >> flavors of for-each. Serial and parallel. Note: These same ideas have > >> been proposed in issue 63 <#Issue63> and issue 4 <#Issue4> but both > >> of those issues could be resolved in ways that do not necessarily use > >> the for-each construct. Therefore I am proposing for-each on its own. > >> If 63 and 4 are closed by introducing serial and parallel for-each > >> then this issue can also be closed. > >> *Submitter's proposal:* > >> > >> > >> <foreach iteratorVariableName="ncname" iteratorVariableType="qname"\ > >> parallel="xs:Boolean" standard-attributes> > >> standard-elements > >> <expression expressionLanguage="anyURI">...</query> > >> activity > >> </foreach> > >> The expression element would be responsible for returning a node-set > >> with 0 or more nodes in it. Each node MUST be of the type specified > >> by iteratorVariableType. > >> > >> If parallel equals false then each node would be assigned, serially > >> and in document order, to the variable created in an implicit local > >> scope by the attribute iteratorVariableName and the activity would be > >> executed. After the activity successfully completes the variable > >> would be assigned to the next node and the activity run again. > >> > >> If parallel equals true then a series of parallel scopes, with the > >> same operational semantics as parallel executing event handlers, > >> equal in number to the number of nodes in the node-set would be > >> created and each node would be assigned to a variable local to each > >> of the scopes. > >> > >> Note that the scope in which the iterator variable is defined is > >> local to the foreach activity and does not contain either an implicit > >> fault or compensation handler. The lack of these handlers is very > >> similar to the logic that was discuss at the 6/2004 F2F for issue 126 > >> <#Issue126>. > >> > >> For example: > >> > >> > >> foreach iteratorVariableName="anOrder" iteratorVariableType="b:ar"/ > >> expression > >> > >> expressionLanguage="http://www.w3.org/TR/1999/REC-xpath-19991116"; > >> parallel="false" > >> $orderManifest/somePart/ordermanifest/orders > >> ... > >> Would be equivalent to: > >> > >> > >> scope > >> variables > >> variable name="anOrder" type="b:ar" > >> variable name="currentInstanceNum" type="xs:int" > >> sequence > >> assign > >> replace > >> from expressionLanguage="static" > >> "1" > >> to expressionLanguage="xpath" > >> $currentInstanceNum > >> while > >> condition expressionLanguage="xpath" > >> $currentInstanceNum <= > >> count($orderList/somePart/ordermanifest/orders) > >> sequence > >> assign > >> replace > >> from expressionLanguage="xpath" > >> > >> $orderList/somePart/(ordermanifest/orders)[$currentInstanceNum] > >> to expressionLanguage="xpath" > >> $anOrder > >> assign > >> replace > >> from expressionLanguage="xpath" > >> $currentInstanceNum+1 > >> to expressionLanguage="xpath" > >> $currentInstanceNum > >> ... > >> > >> *Links:* Yaron Y. Goland, 25 Mar 2004 > >> <http://lists.oasis-open.org/archives/wsbpel/200403/msg00215.html> > >> Yaron Y. Goland, 25 Mar 2004 > >> <http://lists.oasis-open.org/archives/wsbpel/200403/msg00216.html> > >> *Changes:* 16 Jul 2004 - new issue > >> > >> To comment on this issue, please follow-up to this announcement on > >> the wsbpel@lists.oasis-open.org list (replying to this message should > >> automatically send your message to that list), or ensure the subject > >> line as you send it *starts* "Issue - 147 - [anything]" or is a reply > >> to such a message. If you want to formally propose a resolution, > >> please start the subject line "Issue - 147 - Proposed resolution", > >> without any Re: or similar. > >> > >> To add a new issue, see the issues procedures document (but the > >> address for new issue submission is the sender of this announcement). > >> > >> To unsubscribe from this mailing list (and be removed from the roster > >> of the OASIS TC), go to > >> > http://www.oasis-open.org/apps/org/workgroup/wsbpel/members/leave_workgroup.php. > > >> > > > > > > To unsubscribe from this mailing list (and be removed from the roster > > of the OASIS TC), go to > > > http://www.oasis-open.org/apps/org/workgroup/wsbpel/members/leave_workgroup.php. > > > > > > >
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