UML Statechart semantics Speaker: Fei Mo Tutor: Priv.-Doz. Dr. Thomas Noll Lehrstuhl für Informatik 2 RWTH Aachen SS 07

Contents Introduction Fundamentals Semantik of UML Statechart Extended Hierarchical Automata Statechart with STATEMATE Summary

Introduction formulate the semantics of UML Statechart We show how the Extended hierarchical Automata represent statecharts We show the Statechart in STATEMATE

Contents Introduction Fundamentals Semantik of UML Statechart Extended Hierarchical Automata Statechart with STATEMATE Summary

Fundamentals Hierarchy Humans not capable to understand systems containing more than ~5 objects. Most actual systems require more objects Behavioral hierarchy Structural hierarchy Timing behavior.

Introducing hierarchy super-state S sub-states

Contents Introduction Fundamentals Semantik of UML Statechart Extended Hierarchical Automata Statechart with STATEMATE Summary

Semantik of UML Statechart State a condition during the life of an object or an interaction Simple State rectangle with rounded corners The name tab The action label entry exit do include

Composite State State Composite State

Composite states – concurrent substates - using -and- relationship each substate separated from others by dotted line – disjoint substates - using -or- relationship transitions between substates Example of concurrent substates

Configuration A maximum set of states (C) that the system can be simultaneously in C contains root state If C contains OR-state A, it must contain only one of A’s substates If C contains AND-state A, it must contain all of A’s substates Basic configuration is a maximal set of basic states that the system can be in simultaneously Subconfiguration

Semantik of UML Statechart Event Triggers the transition Can be either internally or externally generated Conditions: Guards the transition from being taken unless it is true when event occurs

Semantik of UML Statechart Transition Simple transition a relationship between two states source state of t1 is a directly or transitively nested substate of the source state of t2 -> t1 is higher than t2 Start and end transitions

Semantik of UML Statechart Transition The exact sequence of actions first: the exit actions of all states left by the transition are executed starting the deepest one in the hierarchy next: the action associated to the transition is performed finally: the entry actions of states entered by the transition starting with the highest one in the hierarchy

Semantik of UML Statechart Transition Transitions to and from Concurrent States multiple source states and target states

Semantik of UML Statechart example s0 refined: s1, s2, and s3 composite state: s0, s1, s4 s5; concurrent state: s1 Configurations "System states“: {s1; s6; s8}; {s2}; {s3} Transition fire: source state is in the current configuration trigger is offered by the external environment the guard is satisfied

Semantik of UML Statechart Initial subconfiguration {n8, n6} – b -> t6; next subconfiguration: {n5, n6}; sequence – a -> t3, t2; {n9, n7}; ; if s8 active: no t1 (s8 lower than s4) – e ∈ Π\{a, b}, No transtion, configuration does not change

Contents Introduction Fundamentals Semantik of UML Statechart Extended Hierarchical Automata Statechart with STATEMATE Summary

Extended hierarchical Automata Definition Sequential Automaton A sequential automaton A is a 4-tuple is a finite set of states is the initial state is a finite set of transition labels (labels have a particular structure) is the transition relation

Extended hierarchical Automata Definition Extended hierarchical Automata An EHA consists of a set of sequential automata An EHA is a 5-tuple F is a finite set of sequential automaton E is a finite set of events V is the set of variables ρ is refinement function

Extended hierarchical Automata UML Statechart example

Extended hierarchical Automata Extended hierarchical Automata example Extended Hierarchical Automata can represent statecharts

Extended hierarchical Automata the refinement function ρ; ρ(S) = {TV, USER}, ρ(OFF) = {POWER}, ρ(ON) = {IMAGE,SOUND} ρ(s) = ∅ for any other state s in EHA: dotted arrows. Initial states: indicated by thick boxes. Non-inter-level transitions: represented in the obvious way.

Extended hierarchical Automata The source restriction of transition on: STB Join transitions: a set of states target determinator (TD) transition from ON to STB -> off 1 TD of the transition off1: {STB}; TD of the transition on: {SHW, SND}.

Contents Introduction Fundamentals Semantik of UML Statechart Extended Hierarchical Automata Statechart with STATEMATE Summary

Statechart with STATEMATE STATEMATE system structurefunctionAction Module-charts Activity-charts Statecharts

Statechart with STATEMATE In Conf. {S,S1,A,B,D,E} Event a trigers a/b Event b trigers b/c? what with Event d?

Contents Introduction Fundamentals Semantik of UML Statechart Extended Hierarchical Automata Statechart with STATEMATE Summary

UML Statechart Semantics Can describe the behavior of instances of a model element. Describe sequences of states (rounded boxes) and transitions (arrows). Can describe behavior of use cases and subsystems. Extended Hierarchical Automata can represent statecharts Can be used in STATEMATE to descript separated actions as a more universal design methodology

References [1] Unified Modeling Language Document Set. Version1. 1, Rational Software Corporation, [2] OMG Unified Modeling Language Specification, version 2.1.1, Object Management Group, Inc., [3] Mikk E, Lakhnech Y, Petersohn C, Siegel M. On formal semantics of Statecharts as supported by STATEMATE. In: Duke D, 1997 [4] Evans A, eds. Proceedings of the 2nd BCS-FACS Northern Formal Methods Workshop. London: Springer-Verlag, [5] Harel D, Naamad A. The STATEMATE semantics of statecharts[J]. ACM Transactions on Software Engineering and Methodology, 1996.

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