State Machines Explained

Summary

State machines belong to the domain of computer science and engineering, specifically the sub-domain of finite state machines.

A state machine is a model of behavior composed of a set of states, transitions between those states, and actions taken when in those states. State machines are used to represent and control the behavior of a system.

Creating a state machine can be a good thing for many reasons. State machines can help make complex systems easier to understand, debug, and maintain. They can also provide a solid foundation for implementing logic and handling events. State machines can also help create efficient, reliable, and scalable systems that can handle a large number of concurrent requests.

Code Example

using System;

public enum State
{
    Initial,
    State1,
    State2,
    State3,
    Final
}

public class StateMachine
{
    private State _currentState;

    public StateMachine()
    {
        _currentState = State.Initial;
    }

    public void Transition(State state)
    {
        _currentState = state;
    }

    public State GetCurrentState()
    {
        return _currentState;
    }
}

public class Program
{
    public static void Main()
    {
        var machine = new StateMachine();

        // Perform state transitions
        machine.Transition(State.State1);
        machine.Transition(State.State2);
        machine.Transition(State.State3);
        machine.Transition(State.Final);

        // Output current state
        Console.WriteLine($"Current state: {machine.GetCurrentState()}");
    }
}

State Inverse

The inverse of a state machine is a transition machine, which is a machine that moves from one state to another in response to a given input.

using System;

public class TransitionMachine
{
    public static void Main()
    {
        string currentState = "initial state";
        string nextState = "";

        while(nextState != "final state")
        {
            switch (currentState)
            {
                case "initial state":
                    Console.WriteLine("State 1");
                    nextState = "state 2";
                    break;
                case "state 2":
                    Console.WriteLine("State 2");
                    nextState = "state 3";
                    break;
                case "state 3":
                    Console.WriteLine("State 3");
                    nextState = "final state";
                    break;
            }
            currentState = nextState;
        }
    }
}

State machines are useful in architecture because they provide an efficient way to model complex, dynamic interactions between components. State machines provide a formal way of representing the behavior of components in a system and allow for the modeling of potential interactions between components. This helps to ensure that the system behaves as expected and also makes it easier to identify potential points of failure. State machines are also useful for debugging and validating systems, as it is easy to trace a system’s behavior and identify any issues.

State Machine Architectures

  • Automating a customer support system: State machines can be used to automate customer support systems by providing a set of predefined states and transitions between them.
  • Processing financial transactions: State machines can be used to process financial transactions such as payments and transfers by keeping track of the progress of the transaction.
  • Managing an inventory system: State machines can be used to manage an inventory system by tracking the status of products, such as when they are received, shipped, and returned.
  • Automating a workflow: State machines can be used to automate a workflow by providing a set of predefined states and transitions between them.
  • Controlling a manufacturing process: State machines can be used to control a manufacturing process by tracking the progress of each stage of the process.