02291: System Integration UML State Machines Hubert Baumeister - - PowerPoint PPT Presentation

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02291: System Integration UML State Machines Hubert Baumeister - - PowerPoint PPT Presentation

Oct 04, 2023 180 likes •434 views

02291: System Integration UML State Machines Hubert Baumeister huba@dtu.dk DTU Compute Technical University of Denmark Spring 2020 UML diagrams Wikipedia Example Task: Implement a control panel for a safe in a dungeon The safe

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02291: System Integration

UML State Machines Hubert Baumeister

huba@dtu.dk

DTU Compute Technical University of Denmark

Spring 2020

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UML diagrams

Wikipedia

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Example

◮ Task: Implement a control panel for a safe in a dungeon ◮ The safe should be visible only when a candle has been removed ◮ The safe door opens only when the key is turned after the candle has been replaced again ◮ If the key is turned without replacing the candle, a killer rabbit is released

Safe

  • pen : bool
  • pen

close SecurePanelController doorClosed : bool candleIn : bool candleRemoved() keyTurned() closeSafe()

  • revealLock()
  • releaseKillerRabbit()
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Example

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Example Execution (Secret Panel Controller)

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Example Execution (Safe)

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Example Execution (Secret Panel Controler)

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Example Execution (Safe)

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Example Execution (Secret Panel Controler)

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States 1

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States 2

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Transitions

state state trigger [guard] / effect

UML User Manual 2nd edition

state state

  • peration [guard] / action1; action2; ...
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Example Transition

Open Lock SecretPanelController doorClosed : bool candleIn : bool ... candleRemoved() keyTurned() ...

  • releaseKillerRabbit()

... Transition of the LSM for the SecretPanelController Transition of the LSM for the Safe Safe

  • pen : boolean
  • pen()

close() Open Closed close turnKey [candleIn] / safe.open() safe 1

  • pen
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How to use State Machines

◮ In general:

◮ Focus on states and how a system reacts to events ◮ e.g. modal user interfaces ◮ e.g. hardware controller

◮ Model the life of an object

→ Life cycle state machine (LSM) → From the creation of the object to its destruction → Methods are events

◮ Model the allowed interaction between components

◮ Communication protocols → Protocol state machines (PSM)

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Life cycle state machines

Safe

  • pen : bool
  • pen

close SecurePanelController doorClosed : bool candleIn : bool candleRemoved() keyTurned() closeSafe()

  • revealLock()
  • releaseKillerRabbit()

Open Lock Wait candleRemoved[doorClosed]/this.revealLock closeSafe/safe.close() keyTurned[candleIn]/safe.open()

  • pen

closed

  • pen

close

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Life cycle state machine (LSM)

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Life cycle state machine: Possible implementation

public class SecretPanelController { enum states { wait, lock, open, finalState }; states state = states.wait; public void candleRemoved() { switch (state) { case wait: if (doorClosed()) { state = states.lock; break; } } } public void keyTurned() { switch (state) { case lock: if (candleIn()) { state = states.open; safe.open(); } else { state = states.finalState; releaseRabbit(); } break; } } ... }

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Life Cycle State Machine of a counter

Counter c : int inc dec

Initial state c = 0 and all the time c ≥ 0

public Counter() { c = 0;} public void inc() { c++; } public void dec() { if (c > 0) { c--; ]}

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Nonorthogonal sub states

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Sub states II: Leaving sub states

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Orthogonal Sub states

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History states

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Activity diagrams compared with State machines

Activity diagram

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Activity diagrams compared with State Machine

Activity Diagram State Machine