The Impact of Class Model Redesign on State Machines

Change is a constant factor in software development process It should come as side effect Domino effect: Change to sequence diagrams impacts the corresponding collaboration diagrams. .. Redesign class models impacts on state machines Pattern Application Structure of State Machines [UML Standard] If a composite state is active and not orthogonal, at most one of its substates is active Each region has a set of mutually exclusive disjoint subvertices and a set of transitions If the composite state is active and orthogonal, all of its regions are active, with at most one substate in each region. .. State invariants are associated with states F(self) specifies what has to be true about the object self when it is in the corresponding state We reflect the structure of state machines by entailment relation SM Structure vs. Entailment Invariant monotonicity: for every state s 1 and its superstate s 2 and the corresponding invariants F 1 (self) and F 2 (self) : F 1 ⇒ F 2 States in a state machine are non-overlapping if for every or-state s and every two different substates s 1 and s 2 , the conjunction of the corresponding invariants F 1 ∧ F 2 is false. . .