Issue 14992: UML input pins do not accept more tokens than their actions can immediately consume (fuml-ftf) Source: NIST (Dr. Conrad Bock, conrad.bock(at)nist.gov) Nature: Revision Severity: Significant Summary: UML input pins do not accept more tokens than their actions can immediately consume. The execution engine should reflect this. The Activities, Action, Semantics, item 1, says "The object flow prerequisite is satisfied when all of the input pins are offered all necessary tokens and accept them all at once, precluding them from being consumed by any other actions. This ensures that multiple action executions competing for tokens do not accept only some of the tokens they need to begin, causing deadlock as each execution waits for tokens that are already taken by others." The "necessary tokens" in the first sentence above are the ones needed to execute the actions (meeting the minimum multiplicity), but should include any additional ones offered up the maximum multiplicity. Only these are accepted by the input pins, then immediately consumed by the action. The second sentence gives the motivation, which is to avoid having tokens in input pins that are not immediately consumed. This would prevent those tokens from being used to execute other actions, potentially creating deadlock or starvation. Deadlock is discussed more in issue 7221 of the UML 2.0 FTF report (http://doc.omg.org/ptc/04-10-01). This is also clarified in the revised text for UML RTF issue 13914. Resolution: Resolution: The resolution to Issue 14550, in response to UML Issue 13914, changes the fUML semantics so that the fUML semantics reflect the constraint discussed in the issue. Revised Text: None. Disposition: Duplicate/Merged Revised Text: Actions taken: January 10, 2010: received issue July 23, 2010: closed issue Discussion: End of Annotations:===== m: webmaster@omg.org Date: 19 Jan 2010 16:49:35 -0500 To: Subject: Issue/Bug Report ******************************************************************************* Name: Conrad Bock Company: NIST mailFrom: conrad.bock@nist.gov Notification: Yes Specification: fUML Beta 2 Section: FormalNumber: ptc/2009-10-05 Version: RevisionDate: Page: Title: UML input pins do not accept more tokens than their actions can immediately consume. Nature: Revision Severity: Significant test: 3qw8 B1: Report Issue Description: UML input pins do not accept more tokens than their actions can immediately consume. The execution engine should reflect this. The Activities, Action, Semantics, item 1, says "The object flow prerequisite is satisfied when all of the input pins are offered all necessary tokens and accept them all at once, precluding them from being consumed by any other actions. This ensures that multiple action executions competing for tokens do not accept only some of the tokens they need to begin, causing deadlock as each execution waits for tokens that are already taken by others." The "necessary tokens" in the first sentence above are the ones needed to execute the actions (meeting the minimum multiplicity), but should include any additional ones offered up the maximum multiplicity. Only these are accepted by the input pins, then immediately consumed by the action. The second sentence gives the motivation, which is to avoid having tokens in input pins that are not immediately consumed. This would prevent those tokens from being used to execute other actions, potentially creating deadlock or starvation. Deadlock is discussed more in issue 7221 of the UML 2.0 FTF report (http://doc.omg.org/ptc/04-10-01). Subject: RE: issue 14992 -- fuml FTF issue Date: Wed, 20 Jan 2010 12:34:07 -0500 X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: issue 14992 -- fuml FTF issue thread-index: AcqZ8bu1H3tOXXCdRnumI62rZYymCwABO2Lg From: "Ed Seidewitz" To: Conrad . Agreed. UML Issue 13914 is already one of the ones mentioned in fUML Issue 14550 on revising fUML for UML 2.3. -- Ed -------------------------------------------------------------------------------- From: Juergen Boldt [mailto:juergen@omg.org] Sent: Wednesday, January 20, 2010 11:55 AM To: issues@omg.org; fuml-ftf@omg.org Subject: issue 14992 -- fuml FTF issue From: webmaster@omg.org Date: 19 Jan 2010 16:49:35 -0500 To: Subject: Issue/Bug Report ******************************************************************************* Name: Conrad Bock Company: NIST mailFrom: conrad.bock@nist.gov Notification: Yes Specification: fUML Beta 2 Section: FormalNumber: ptc/2009-10-05 Version: RevisionDate: Page: Title: UML input pins do not accept more tokens than their actions can immediately consume. Nature: Revision Severity: Significant test: 3qw8 B1: Report Issue Description: UML input pins do not accept more tokens than their actions can immediately consume. The execution engine should reflect this. The Activities, Action, Semantics, item 1, says "The object flow prerequisite is satisfied when all of the input pins are offered all necessary tokens and accept them all at once, precluding them from being consumed by any other actions. This ensures that multiple action executions competing for tokens do not accept only some of the tokens they need to begin, causing deadlock as each execution waits for tokens that are already taken by others." The "necessary tokens" in the first sentence above are the ones needed to execute the actions (meeting the minimum multiplicity), but should include any additional ones offered up the maximum multiplicity. Only these are accepted by the input pins, then immediately consumed by the action. The second sentence gives the motivation, which is to avoid having tokens in input pins that are not immediately consumed. This would prevent those tokens from being used to execute other actions, potentially creating deadlock or starvation. Deadlock is discussed more in issue 7221 of the UML 2.0 FTF report ( http://doc.omg.org/ptc/04-10-01). This is also clarified in the revised text for UML RTF issue 13914. Juergen Boldt Director, Member Services Object Management Group 140 Kendrick St Building A Suite 300 Needham, MA 02494 USA tel: +1 781 444 0404 x 132 fax: +1 781 444 0320 email: juergen@omg.org www.omg.org This is also clarified in the revised text for UML RTF issue 13914.