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Subject: Re: [wsbpel] Issue - 252 - Behaviour when return value of expressionsis incorrect is not defined
Hi DK and Danny, Actually after more thinking, there may be a reasonable (not too heavy handed) way to *define* when a runtime fault is thrown when values from an expression cannot be converted into a target schema type. However, I think we should address this definition in the context of default XPath1.0-to-WSBPEL2.0 binding/handshaking (i.e. "urn:oasis:names:tc:wsbpel:2.0:sublang:xpath1.0"), not in the context of general WS-BPEL expression handling. Because in XPath 2.0 data model, we have more tools to deal with this problem in a more appropriate way. For XPath1.0 data model, it has Number (Double) and Boolean to deal with these expression. Boolean expressions (in transition, join, while, and if conditions) Unsigned Integer expressions (in startCounterValue, finalCounterValue, and branches in forEach) On the other hand, we need to use string in XPath 1.0. Deadline expressions (in until expression of onAlarm and wait) Duration expressions (in for expression of onAlarm and wait, repeatEvery expression of onAlarm) Thanks! Regards, Alex Yiu Dieter Koenig1 wrote: Hi Alex, I am not sure if we have to go this far. Today, we can detect and throw "mismatchedAssignmentFailure" when incompatible types are detected (see 8.4.3) during assignment. This handles any "type incompatibility between from-spec and to-spec". The question is whether we can also detect and throw a new fault during expression evaluation: Boolean expressions (in transition, join, while, and if conditions) Deadline expressions (in until expression of onAlarm and wait) Duration expressions (in for expression of onAlarm and wait, repeatEvery expression of onAlarm) Unsigned Integer expressions (in startCounterValue, finalCounterValue, and branches in forEach) This would address any "type incompatibility between the specified expression and the expectation of BPEL implementation". This situation would otherwise lead to undefined behavior. Instead of saying "the associated activity MUST check explicitly for schema compliance", we may reduce the requirement and just say "if an error is detected then throw the new fault". Kind Regards DK Alex Yiu <ALEX.YIU@ORACLE. COM> To Danny van der Rijn 26.03.2006 08:58 <dannyv@tibco.com>, wsbpel@lists.oasis-open.org cc Alex Yiu <alex.yiu@ORACLE.COM> Subject Re: [wsbpel] Issue - 252 - Behaviour when return value of expressions is incorrect is not defined If we want to handle this issue right, we would likely either create dependencies on XQuery1.0/XPath2.0 spec or duplicate chunks of those specs in this bpel spec. Thanks! Regards, Alex Yiu From Danny van der Rijn <dannyv@tibco.com> Sent Fri 3/24/2006 1:03 PM To wsbpel@lists.oasis-open.org Subject Re: [wsbpel] Issue - 252 - Behaviour when return value of expressions is incorrect is not defined I don't think we agreed to open this issue, did we? ws-bpel issues list editor wrote: This issue has been added to the wsbpel issue list with a status of "open". The TC agreed to accept the issue before it was added to the issue list. The issues list is posted as a Technical Committee document to the OASIS WSBPEL TC pages 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 - 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. Issue - 252 - Behaviour when return value of expressions is incorrect is not defined Status: open Date added: 23 Mar 2006 Categories: Fault handling Submitter: Simon Moser Description: The fault that is thrown when incoming and/or outgoing messages are schema validated SHOULD be the same as that of the explicit validate activity. In Section 8.3.x of the latest spec copy, there are multiple types of expressions. None of these sections talks about what happens when the (XPath) Expression doesn't evaluate to it's designated return value. That is the expression itself gets evaluated successfully, so no fault is thrown during evaluation, but the returned value is not of the type expected. For illustration: In a while activity, which demands a boolean expression, the return value of the expression provided yields a non-boolean return type (that cannot be detected by static analysis because sometimes the return value of e.g. an XPATH expression is not known in advance. The spec should clearly state what should happen in that case. Submitters proposal: A new standard fault bpel:invalidReturnType should be introduced and MUST be thrown in these cases. This is similar to the " mismatchedAssignmentFailure" except that the receiver is not the to-spec but the engine itself. This should be the case for Boolean expressions (transition, join, while, and if conditions) Deadline expressions (until expression of onAlarm and wait) Duration expressions (for expression of onAlarm and wait, repeatEvery expression of onAlarm) Unsigned Integer expressions (startCounterValue, finalCounterValue, and branches in forEach) That means that the associated activity MUST check explicitly for schema compliance. That means Boolean expressions (transition, join, while, and if conditions) MUST be checked against xsd:boolean Deadline expressions (until expression of onAlarm and wait) MUST be checked against xsd:date or xsd:dateTime Duration expressions (for expression of onAlarm and wait, repeatEvery expression of onAlarm) MUST be checked against xsd:duration Unsigned Integer expressions (startCounterValue, finalCounterValue, and branches in forEach) MUST be checked against xsd:unsignedInt Changes: 23 Mar 2006 - new issue To comment on this issue (including whether it should be accepted), 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 - 252 - [anything]" or is a reply to such a message. If you want to formally propose a resolution to an open issue, please start the subject line "Issue - 252 - 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 mail list, you must leave the OASIS TC that generates this mail. You may a link to this group and all your TCs in OASIS at: https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php --------------------------------------------------------------------- To unsubscribe from this mail list, you must leave the OASIS TC that generates this mail. You may a link to this group and all your TCs in OASIS at: https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php |
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