Issue 8332: inconsistent description (uml2-rtf) Source: (, ) Nature: Clarification Severity: Minor Summary: There is an inconsistent description about determining conflicting transitions of a internal transition. According to sector Conflicting transitions, p.492: "Two transitions are said to conflict if they both exit the same state", two internal transitions in the same configration won't be conflict, However, P.492 says "Each orthogonal region in the active state configuration that is not decomposed into orthogonal regions can fire at most one transition as a result of the current event" There are two possible explanation: 1.Internal transition is treated orthogonal to the container region: thus, any two internal transitions in different state won't be confilict. 2.Internal transition is treated as self-transition without entry/exit action: thus, internal transition will be conflict with transitions which are conflict with corresponding self-transition. And a orthogonal region fires at most one transition(either internal or non-internal) an example: A and B are two states of top state. A is superState of AA AA is superState of AAA and AAB t1 is an internal transition of A t2 is an internal transition of AA t3 is an external transition from AAA to AAB t4 is an external transition from AA to B does t1 and t2 conflict? t2 and t3? which should be chosen for firing? Resolution: Discussion An internal transition IS a self-transition. It does not exit or enter the state to which it is attached. Internal transitions belong to states and not to regions, as seemed to be implied by the issue summary. This is explicitly stated in the specification. From the point of view of firing rules, they are no different than for any other transition. If there are conflicts (and, there CAN be conflicts between two internal transitions), they are resolved the same way as all other conflicts based on the firing rules for such cases. Hence, the ambiguity discussed in the summary of the issue does not exist. (However, after reading the text, it seems that there is no explicit statement on how the issue of conflicting transitions of the same priority is resolved. Presumably, this is one of those “intentionally left unspecified” cases; i.e., it is an implementation choice. But, this is a different and more general issue that needs to be dealt with separately.) Disposition: Closed - No Change Revised Text: Actions taken: February 24, 2005: received issue February 20, 2015: closed issue Discussion: Disposition: Deferred to UML 2.4 RTF End of Annotations:===== m: webmaster@omg.org Date: 24 Feb 2005 01:17:13 -0500 To: Subject: Issue/Bug Report -------------------------------------------------------------------------------- Name: Rui Xu Company: none mailFrom: shuyiwo@yahoo.com Notification: Yes Specification: inconsistent description determining conflicting transitions of a internal transition Section: 15.State Machines FormalNumber: UML2.0 Superstructure Version: ptc/03-08-02 RevisionDate: 08/02/03 Page: 492 Nature: Clarification Severity: Minor HTTP User Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; MyIE2) Description There is an inconsistent description about determining conflicting transitions of a internal transition. According to sector Conflicting transitions, p.492: "Two transitions are said to conflict if they both exit the same state", two internal transitions in the same configration won't be conflict, However, P.492 says "Each orthogonal region in the active state configuration that is not decomposed into orthogonal regions can fire at most one transition as a result of the current event" There are two possible explanation: 1.Internal transition is treated orthogonal to the container region: thus, any two internal transitions in different state won't be confilict. 2.Internal transition is treated as self-transition without entry/exit action: thus, internal transition will be conflict with transitions which are conflict with corresponding self-transition. And a orthogonal region fires at most one transition(either internal or non-internal) an example: A and B are two states of top state. A is superState of AA AA is superState of AAA and AAB t1 is an internal transition of A t2 is an internal transition of AA t3 is an external transition from AAA to AAB t4 is an external transition from AA to B does t1 and t2 conflict? t2 and t3? which should be chosen for firing?