PSCS11 — Any EventOccurrence should be associatable as an interaction point.

The EventOccurrence class was introduced in fUML 1.2, with SignalEventOccurrence as a subclass. However, PSCS 1.0 only allows a SignalInstance to be associated with the InteractionPoint of the port through which it was sent. This should be changed to allow any EventOccurrence to be associated with an InteractionPoint, so that other types of EventOcurrences may be identified as sent through ports (which is necessary to properly handle them on Triggers with port references).

Any EventOccurrence should be associatable as an interaction point.

Note: The technical changes proposed to PSCS are dependent on issues resolved for fUML 1.3:

­FUML13-23: Enable any kind of event occurrence to be exchanged between active objects.

­FUML13-25: Enable EventOccurrence and its subclasses to provide operations to define trigger matching as well as data extractions semantics.

Proposal: In order to introduce the possibility to send any EventOccurrence through ports and connectors in PSCS, four different groups of changes shall be performed:

1. Classes CS_Object, CS_InteractionPoint and CS_Reference contribute to the event based communications propagation mechanism limited to SignalInstance. These classes must have their send(…), sendIn(…) and sendOut(…) operation signatures and specifications changed to make sure it is allowed to propagate EventOccurrence (cf. section 8.4.3.2.3 in fUML 1.2.1) instead of CS_SignalInstance. These changes directly rely on those proposed in resolution FUML13-23.
2. In PSCS 1.0 only signal instances where intended to be propagated through ports and connectors, hence an extension to SignalInstance was provided. This extension (i.e., CS_SignalInstance) captures the port through which a signal instance was received. The problem here is that this information is not specific to signal instances but general to any kind of event occurrence that might be propagated along ports and connectors. Hence, CS_SignalInstance shall be removed and replaced by CS_EventOccurrence, which must reference an EventOccurrence (i.e., the event occurrence actually propagated) and a CS_InteractionPoint (i.e., the port instance through which the propagated event occurrence has arrived). CS_EventOccurrence must also override operations getParameterValues and match inherited from EventOccurrence.
3. The above two groups of changes imply modifications of the specifications of both CS_AcceptEventActionActivation and CS_SendSignalActionActivation. The changes to CS_AcceptEventActionActivation consist in:
   • Removing the match operation that does not need to be overridden since its specification was changed in FUML13-25 to rely on the matchAny operation provided in EventOccurrence.
   • Overriding the accept operation in order to make sure that if a CS_eventOccurrence is received then the event occurrence that is finally accepted is the wrapped event occurrence.
     The changes to CS_SendSignalActionActivation consist in:
   • Removing the doActionDefault operation which does not need to exist since it does not change the semantics provided by SendSignalActionActivation doAction operation and CS_SignalInstance is removed from the PSCS semantic model.
   • Updating the definition of the doAction operation in order to account for the usage of EventOccurrence instead of SignalInstance or CS_SignalInstance.
4. In FUML13-25, the implementation of ReadIsClassifiedObjectAction doAction operation has changed. Type checking semantics now relies on operations instanceOf and checkAllParents which are both provided by the Value class. This change implies that it is not anymore required for PSCS to provide an extension to ReadIsClassifiedObjectAction. Indeed operations (checkAllParents, isDescendant and realizesInterface) provided in this extension must be moved to CS_Object (which is a kind of Value) to ensure specific type checking semantics related to interfaces is preserved. Since CS_ReadIsClassifierObjectActionActivation does not add semantics to ReadIsClassifierObjectActionActivation it must be removed from the PSCS semantic model.