Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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Getting Dynamic,
State Machine Diagram
PB007 Software Engineering I
Lukáš Daubner
daubner@mail.muni.cz
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Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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State Machine Diagram
̶Models the dynamic behavior (life cycle) of one subject
̶Class instantiation (Object)
̶Use Case
̶System
̶Subsystem
̶Component
̶…
̶
̶Main components are:
̶States
̶Transitions
̶Events
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State
Event
Transition

Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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States
State Machine Diagram
̶Represents semantically important situation
̶In case of (OOP) object, it is determined by attribute values, relations with others, and
performed activity.
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Entry action
Performed when entering the state
Exit action
Performed when exiting the state
Internal activity
Ongoing behavior while
in the state
Deferrable Trigger
Event, which is registered but its
processing is left for other states
Internal Transition
Transition, which is processed
without exiting the sate

Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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Transitions
State Machine Diagram
̶Defines how to get from one state to another
̶Syntax: event [guard condition] / action
̶Semantics: At the occurrence of event, if the guard condition holds, perform action and go to the
new state.
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Event
Condition (bool)
Action

Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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Events
State Machine Diagram
̶Stimulus on which the subject may react by changing the state or performing an operation.
̶
̶Types of events:
̶Call event – Calling operation of the subject.
̶Signal event – Asynchronous sending a receiving a signal between subjects
̶Change event – Boolean expression. The event occurs when the value is changed from false to true.
̶Time event – Event occur at a certain time t (when(t)) or after a certain time t (after(t)).

Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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Events
State Machine Diagram
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Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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Simple composite state
Composite States
̶Useful for simplifying the diagram
̶Capturing inheritance between states
̶Consist of a single region
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Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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Orthogonal composite state
Composite States
̶Capturing parallel behavior
̶Consist of a two and more regions
̶
̶
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Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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State Machine Diagram in OOP world
̶In our case, state machine diagram is used to represent lifecycle of an object
̶Context of the diagram is only the instance of a class from design class diagram
̶All methods and events must be supported by the design class diagram
̶Initial transition means calling the constructor
̶Final transition means deleting the object from system
̶Object saves its state even outside main memory (persistence)

Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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State Machine Diagram in OOP world

Adobe Systems
PB007 Software Engineering I — Getting Dynamic, State Machine Diagram
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You gotta do what you gotta do
Task for this week
̶Process the feedback
̶
̶Choose a suitable object for modeling - ride
̶Something with non-trivial lifecycle
̶
̶Create a state machine diagram for this object
̶Revise design class diagram if needed
̶