Statecharts Used to model behaviour of Autonomous and Reactive Systems (event driven, react to internal –timeouts– and external stimuli) Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 1/16
Statecharts • Visual formalism yet formally and rigourously defined for 1. documentation 2. analysis (model checking as well as testing) 3. simulation 4. code synthesis • Solves FSA problems (by combining with Higraphs): 1. flat ⇒ hierarchy ( ⇒ re-use) 2. represent large number of transitions concisely 3. represent large number of states concisely Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 2/16
Statecharts references • David Harel. Statecharts: A Visual Formalism for Complex Systems. Science of Computer Programming. vol. 8. 1987. pp. 231 - 274. David Harel. On Visual Formalisms. • Communications of the ACM. Volume 31, No. 5. 1988. pp. 514 - 530. • David Harel and Amnon Naamad. The STATEMATE semantics of statecharts. ACM Transactions on Software Engineering and Methodology (TOSEM) vol. 5. Issue 4. October 1996. pp.293 - 333. • David Harel and Hillel Kugler. The Rhapsody Semantics of Statecharts (or, On the Executable Core of the UML). Springer, Lecture Notes in Computer Science 3147. 2004. pp. 325 - 354. Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 3/16
Statecharts tools • STATEMATE [http://www.ilogix.com/products/magnum/index.cfm] • Rhapsody [http://www.ilogix.com/products/rhapsody/rhap_inc.cfm] • Rational Rose [http://www.rational.com] • Stateflow [http://www.mathworks.com/products/stateflow/] • BetterState Lite [http://www.windriver.com/products/html/betterstate.html] • XJTek [http://www.xjtek.com/products/xjcharts/] • Poseidon for UML [http://www.GentleWare.com] • ArgoUML [http://argouml.tigris.org/] • visualSTATE [http://www.iar.com/Products/VS/] • SVM [http://msdl.cs.mcgill.ca/people/tfeng/research.html] Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 4/16
Statecharts = 1. Deterministic Finite State Automata (FSA, DFA) 2. Depth 3. Orthogonality 4. Broadcast 5. History 6. Time 7. syntactic sugar: entry/exit actions, . . . Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 5/16
UML 2.0 Statecharts abstract syntax Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 6/16
Deterministic Finite State Automata (FSA, DFA) State A A entry/ ... �� �� �� �� do/ ... exit/ ... A e Default state (pseudo state) f/a �� �� �� �� g [guard] B g(2,"a") transition event(params) [guard] /output_action(params) C e Not allowed in DFA ! Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 7/16
Depth (XOR) Statechart with depth State automaton give meaning by "flattening" �� �� �� �� �� �� �� �� X �� �� �� �� A A e e f g f g B B f C C Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 8/16
Depth and determinism Statechart with depth State automaton (non deterministic) give meaning by "flattening" �� �� �� �� �� �� �� �� �� �� X �� �� A A e e f f f f B B f C C Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 9/16
Depth and determinism State automaton (non deterministic) A e f f B f C Deterministic state automaton Deterministic state automaton outer transition (STATEMATE) inner transition (UML) A A e e f f B B f f C C Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 10/16
Why “inner-first” in UML Statecharts ? outer1 outer2 e e() g() outer2 e inner1 f(2,"hello") outer3 g inner1 inner2 inner2 e() f(int, string) Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 11/16
Orthogonality (AND) meaning State Automaton Statechart with Orthogonal Components �� �� �� �� �� �� �� �� Y A D k �� �� B,F �� �� h B E k �� �� g �� �� B,E e B,G g h F f[D in(G)] e m|p e e f G e p C g m C,E p C,G n e p p k e p e C,F H I n h p m|p I H Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 12/16
Orthogonality and synchronization Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 13/16
Broadcasting (output events) A D E h B F n g e f/g C G e H m/e I J n/f Input Segment: nmnn Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 14/16
History States Autonomous H resume Red t Manual to_manual Green t Yellow t Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 15/16
Deep History H* A OC2 OC1 C B X I Y D J Z Modelling of Software-Intensive Systems (MoSIS) hv@cs.mcgill.ca Statecharts 16/16
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