OTS — Predefined SignalSets require predefined Outcomes

The following section is taken from the Activity srevice specification
orbos/2000-06-19.
P48 "The Synchronization SignalSet has a similar role to that of
Synchronization objects within the OTS, i.e., it is invoked before and
after completion of the
Activity. Likewise, the completion status of an Activity may be changed by
the Actions registered with this SignalSet, such that the Activity?s
outcome when
postCompletion is called may be different to that when preCompletion was
invoked. If an Action error occurs during preCompletion (e.g., the
ActionError
exception is thrown) then the Activity completion status will be set to
CompletionStatusFailOnly."

In order for an Action itself to influence the completion status of an
Activity during signal processing, it must cause the SignalSet responsible
for the Signal being processed to set the appropriate completion status.
This is achieved through the Outcome the Action returns from the
process_signal call. In the case of the predefined SignalSets, no
predefined Outcomes are specified so there is no opportunity for an Action
processing the preCompletion signal to influence the completion status. The
object model for the Activity service does not encourage an Action to
invoke methods directly on a SignalSet (such as
SignalSet::set_completion_status) and Current::set_completion_status may
not be called after the completion SignalSet has started producing signals.
Therefore predefined Outcomes, that may be generated by Actions, are
required for the predefined SignalSets and the behaviour of these
predefined SignalSets, in terms of how they react to the predefined
Outcomes, needs to be specified. Per the specification, there is no need
for the predefined SignalSets themselves to produce an Outcome.

I propose the following predefined Outcomes: "org.omg.preCompletionSuccess"
and "org.omg.preCompletionFailed" that may be generated by Actions and
passed to the Synchronization SignalSet via the ActivityCoordinator calling
set_response. On receipt of the org.omg.preCompletionFailed Outcome during
preCompletion, the Synchronization SignalSet should set its completion
status to CompletionStatusFailOnly.

see above