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Subject: AW: AW: [wsbpel] Issue - 147 - Serial and Parallel For-Each
Oh, I didn't catch that, Yaron: Are saying that the activity nested in a <foreach> must not have output variables? Mit besten Grüßen, Frank Leymann Phone:......+49-711-7816 470 Mobile:.....+49-162-322 4444 e-Mail: Frank.Leymann@informatik.uni-stuttgart.de -----Ursprüngliche Nachricht----- Von: Yaron Y. Goland [mailto:ygoland@bea.com] Gesendet: Friday, July 16, 2004 6:37 PM An: Frank Leymann Cc: wsbpel@lists.oasis-open.org Betreff: Re: AW: [wsbpel] Issue - 147 - Serial and Parallel For-Each 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. >
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