The following sections describe the object-oriented interpretation
of statecharts.
Single message run-to-completion processing IBM Rational Rhapsody assumes
that statecharts react to a single message applied by some external
actor to the statechart. The external actor can be either the system
event queue or another object.
Transition selection
Transition selection specifies which subset of active transitions
to fire.
Conflicts
Two transitions are said to conflict if
both cause the same state to exit. Only orthogonal or independent
transitions fire simultaneously. This means that interleaved execution
causes equivalent results. Disjoint exit states are a satisfactory
condition for equivalent results.
Priorities Priorities resolve some, but not all, transition
conflicts. IBM Rational Rhapsody uses
state hierarchies to define priorities among conflicting transitions.
However, lower-level (nested) states can override behaviors, thus
implying higher priority.