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What is hierarchical finite state machine?
Hierarchical state machines are finite state machines whose states themselves can be other state machines. Hierarchy is a useful con- struct in many modeling formalisms and tools for software design, requi- rements and testing.
Do finite state machines need a final state?
Deterministic Finite State Machines From any state, there is only one transition for any allowed input. The output of a state machine is its final state. It goes through all its processing, and then the final state is read, and then an action is taken.
What is a state in a finite state machine?
A state is a situation of a system depending on previous inputs and causes a reaction on following inputs. One state is marked as the initial state; this is where the execution of the machine starts. A state transition defines for which input a state is changed from one to another.
Is the state machine always in a leaf state?
During operation the state machine is always in a leaf state. So transitions ultimately lead from one leaf state to another. If a transition is drawn to target a composite state, the composite state needs to specify one of its substates as the initial state.
What is the best practice for a hierarchical state machine?
For making a HSM with the state pattern, each state with substates has to be a state machine itself. This way it the upper level has no knowledge of the substates (less side effects) and the state can better manage his substates (can have a default state, can remember the last state it was in etc).
Which is an example of a finite state machine?
Most of you are probably familiar with state machines. Finite state machines (FSMs) are widely used in both digital electronics and programming. Applications include communication protocols, industrial control or GUI programming. UML includes a more flexible variant in the form of statechart diagrams.