Finite State Machine
A mathematical model of computation. An abstract FSM can be in one of the finite number of states at a given point of time.
- State
A status of the system. - Transition
A change from one state to another. Based on input events.
Statechart Diagram
Described temporal evolution of an object of a given class in reponse to interactions with other objects.
Event
One-way communication between 2 objects. Atomic (non-interruptible), asynchronous. May cause a transition.
State
Depicted as a rounded rectangle with upto 3 sections. Might be
- name - optional
- state variables
- triggered operations
- entry event
Occurs when entering the state - exit event
Occurs when exiting the state
Operation
An atomic action invoked by a transition.
Activity
An ongoing operation that takes place while object is in a given state.