What is a sub state machine?

What is a sub state machine?

It is common for a character to have complex actions that consist of a number of stages. Rather than handle the entire action with a single state, it makes sense to identify the separate stages and use a separate state for each. These collapsed groups of states are called Sub-state machines. …

What is described in a state machine model?

A state machine model is a mathematical model that groups all possible system occurrences, called states. Every possible state of a system is evaluated, showing all possible interactions between subjects and objects. If every state is proven to be secure, the system is proven to be secure.

What is Composite state in state diagram?

Composite States are composed within the StateMachine diagram by expanding a State element, adding Regions if applicable, and dragging further State elements, related elements and connectors within its boundaries. The internal State elements are then referred to as Substates.

Why are state machines important?

State Machines are used in applications where distinguishable states exist. Each state can lead to one or multiple states and can also end the process flow. A State Machine relies on user input or in-state calculation to determine which state to go to next.

How does a hierarchical state machine capture commonality?

Hierarchical state machine design captures the commonality by organizing the states as a hierarchy. The states at the higher level in hierarchy perform the common message handling, while the lower level states inherit the commonality from higher level ones and perform the state specific functions.

Why are Harel state machines called hierarchical state machines?

Harel statecharts bring the “Ultimate Hook” pattern to the logical conclusion by combining it with the state machine formalism. The most important innovation of statecharts over the classical FSMs is the introduction of hierarchically nested states (that’s why statecharts are also called hierarchical state machines ).

How is state nesting used in hierarchical state machines?

The fundamental character of state nesting in Hierarchical State Machines (HSMs) comes from combining hierarchy with programming-by-difference, which is otherwise known in software as inheritance.

How are hierarchical state machines used in embedded systems?

The formalism of Hierarchical State Machines (aka statecharts) makes the state machine approach truly applicable to real-life embedded systems. In State Machines for Event-Driven Systems, I touched on the benefits of using state machines in programming reactive (event-driven) systems.