Philiprehberger.StateMachine
0.3.0
dotnet add package Philiprehberger.StateMachine --version 0.3.0
NuGet\Install-Package Philiprehberger.StateMachine -Version 0.3.0
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<PackageReference Include="Philiprehberger.StateMachine" Version="0.3.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageVersion Include="Philiprehberger.StateMachine" Version="0.3.0" />
<PackageReference Include="Philiprehberger.StateMachine" />
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package.
paket add Philiprehberger.StateMachine --version 0.3.0
The NuGet Team does not provide support for this client. Please contact its maintainers for support.
#r "nuget: Philiprehberger.StateMachine, 0.3.0"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
#:package Philiprehberger.StateMachine@0.3.0
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package.
#addin nuget:?package=Philiprehberger.StateMachine&version=0.3.0
#tool nuget:?package=Philiprehberger.StateMachine&version=0.3.0
The NuGet Team does not provide support for this client. Please contact its maintainers for support.
Philiprehberger.StateMachine
Lightweight finite state machine with fluent configuration, guard conditions, and async transition support.
Installation
dotnet add package Philiprehberger.StateMachine
Usage
using Philiprehberger.StateMachine;
enum State { Locked, Unlocked }
enum Trigger { Coin, Push }
var machine = new StateMachineBuilder<State, Trigger>()
.Configure(State.Locked)
.Permit(Trigger.Coin, State.Unlocked)
.Configure(State.Unlocked)
.Permit(Trigger.Push, State.Locked)
.Build(State.Locked);
machine.Fire(Trigger.Coin);
// machine.CurrentState == State.Unlocked
Guard Conditions
var machine = new StateMachineBuilder<State, Trigger>()
.Configure(State.Locked)
.PermitIf(Trigger.Coin, State.Unlocked, () => HasValidCoin())
.Build(State.Locked);
bool canFire = machine.CanFire(Trigger.Coin);
var permitted = machine.GetPermittedTriggers();
Entry and Exit Actions
var machine = new StateMachineBuilder<State, Trigger>()
.Configure(State.Unlocked)
.OnEntry(() => Console.WriteLine("Gate opened"))
.OnExit(() => Console.WriteLine("Gate closing"))
.Permit(Trigger.Push, State.Locked)
.Build(State.Unlocked);
Async Actions
var machine = new StateMachineBuilder<State, Trigger>()
.Configure(State.Locked)
.OnEntryAsync(async () => await NotifyAsync("Locked"))
.OnExitAsync(async () => await LogAsync("Leaving locked"))
.Permit(Trigger.Coin, State.Unlocked)
.Build(State.Locked);
await machine.FireAsync(Trigger.Coin);
Transition History
var machine = new StateMachineBuilder<State, Trigger>()
.WithMaxHistorySize(50)
.Configure(State.Locked)
.Permit(Trigger.Coin, State.Unlocked)
.Configure(State.Unlocked)
.Permit(Trigger.Push, State.Locked)
.Build(State.Locked);
machine.Fire(Trigger.Coin);
foreach (var record in machine.TransitionHistory)
{
Console.WriteLine($"{record.FromState} -> {record.ToState} via {record.Trigger} at {record.Timestamp}");
}
Hierarchical Substates
enum State { Active, Running, Paused, Inactive }
enum Trigger { Start, Pause, Resume, Stop }
var machine = new StateMachineBuilder<State, Trigger>()
.Configure(State.Active)
.Permit(Trigger.Stop, State.Inactive)
.Configure(State.Running)
.SubstateOf(State.Active)
.Permit(Trigger.Pause, State.Paused)
.Configure(State.Paused)
.SubstateOf(State.Active)
.Permit(Trigger.Resume, State.Running)
.Build(State.Running);
machine.IsInState(State.Active); // true (Running is a substate of Active)
machine.CanFire(Trigger.Stop); // true (inherited from Active)
Serialization and Restoration
// Capture a snapshot
var snapshot = machine.Serialize();
string json = JsonSerializer.Serialize(snapshot);
// Restore from snapshot
var deserialized = JsonSerializer.Deserialize<StateMachineSnapshot<State, Trigger>>(json);
var restored = StateMachine<State, Trigger>.Restore(deserialized, builder);
API
StateMachineBuilder<TState, TTrigger>
| Method | Description |
|---|---|
Configure(TState state) |
Begin configuring a state, returns StateConfiguration |
WithMaxHistorySize(int maxSize) |
Set the maximum number of transition history entries (default 100) |
Build(TState initialState) |
Create the state machine with the specified initial state |
StateConfiguration<TState, TTrigger>
| Method | Description |
|---|---|
Permit(TTrigger, TState) |
Allow a transition on the given trigger |
PermitIf(TTrigger, TState, Func<bool>) |
Allow a transition with a guard condition |
OnEntry(Action) |
Execute action when entering this state |
OnExit(Action) |
Execute action when exiting this state |
OnEntryAsync(Func<Task>) |
Execute async action when entering this state |
OnExitAsync(Func<Task>) |
Execute async action when exiting this state |
SubstateOf(TState parentState) |
Declare this state as a substate of the given parent |
StateMachine<TState, TTrigger>
| Member | Description |
|---|---|
CurrentState |
The current state of the machine |
TransitionHistory |
Read-only list of recorded transitions |
MaxHistorySize |
Maximum number of history entries retained |
Fire(TTrigger) |
Fire a trigger synchronously |
FireAsync(TTrigger) |
Fire a trigger asynchronously |
CanFire(TTrigger) |
Check if a trigger can be fired from the current state |
GetPermittedTriggers() |
Get all triggers permitted from the current state |
IsInState(TState) |
Check if the machine is in the given state or a substate thereof |
Serialize() |
Create a JSON-serializable snapshot of the machine |
Restore(snapshot, builder) |
Static method to rebuild a machine from a snapshot |
TransitionRecord<TState, TTrigger>
| Property | Type | Description |
|---|---|---|
FromState |
TState |
The state before the transition |
ToState |
TState |
The state after the transition |
Trigger |
TTrigger |
The trigger that caused the transition |
Timestamp |
DateTimeOffset |
When the transition occurred |
InvalidTransitionException
Thrown when attempting to fire a trigger that is not permitted from the current state.
Development
dotnet build src/Philiprehberger.StateMachine.csproj --configuration Release
Support
If you find this project useful:
License
| Product | Versions Compatible and additional computed target framework versions. |
|---|---|
| .NET | net8.0 is compatible. net8.0-android was computed. net8.0-browser was computed. net8.0-ios was computed. net8.0-maccatalyst was computed. net8.0-macos was computed. net8.0-tvos was computed. net8.0-windows was computed. net9.0 was computed. net9.0-android was computed. net9.0-browser was computed. net9.0-ios was computed. net9.0-maccatalyst was computed. net9.0-macos was computed. net9.0-tvos was computed. net9.0-windows was computed. net10.0 was computed. net10.0-android was computed. net10.0-browser was computed. net10.0-ios was computed. net10.0-maccatalyst was computed. net10.0-macos was computed. net10.0-tvos was computed. net10.0-windows was computed. |
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.
-
net8.0
- No dependencies.
NuGet packages
This package is not used by any NuGet packages.
GitHub repositories
This package is not used by any popular GitHub repositories.