StateMachine

A state machine implemented in Swift.

Installation

CocoaPods

  pod 'JCStateMachine', '~> 1.0.0'

Carthage

  carthage 'jbaptistecastro/StateMachine' "1.0.0"

Classes

State

A state only needs a name.

Create a State object

let myState = State("MyState")

Transition

A transition needs a name, a "from" state and a "to" state.

Create a Transition object

let fromState = State("FromState")
let toState = State("ToState")

let myTransition = Transition("MyTransition", from: fromState, to: toState)

Lifecycle Events

Before a specific transition

beforeTransition(transition)

On leaving a specific state

leaveState(state)

On entering in a specific state

onState(state)

On entering in a specific transition

onTransition(transition)

StateMachine

A state machine takes an initial State and a Transition array.

Create a StateMachine object

let stateA = State("StateA")
let stateB = State("StateB")

let transitionA = Transition("TransitionA", from: stateA, to: stateB)
let transitionB = Transition("TransitionB", from: stateB, to: stateA)

let stateMachine = StateMachine(initialState: stateA, transitions: [transitionA, transitionB]

Fire a Transition

do {
    stateMachine.fire(transition: transitionB, userInfo: nil)
} catch TransitionError.unknown {
    print("Transition unknown)
} catch TransitionError.notAllowed {
    print("Transition not allowed")
} 

Observe a lifecycle event

An event can be observed on a specific queue and can be triggered with a "userInfo" dictionary.

stateMachine.on(.onState(stateB), queue: observeQueue) { (userInfo) in
            
}

Helper functions

Compare a state with the current state

let isCurrent = stateMachine.isCurrent(state: myState)

If a transition can be fired

let canFire = stateMachine.canFire(transition: myTransition)

Get allowed transitions from the current state

let allowedTransitions = stateMachine.allowedTransitions()

Get a state from a specific name

let stateA = stateMachine.state(name: "stateA")

Get registered states

let states = stateMachine.allStates()

Get a transition from a specific name

let transitionA = stateMachine.transition(name: "transitionA")

Get registered transitions

let transitions = stateMachine.allTransitions()

Objective C compatibility

Actually, StateMachine doesn't support Objective C and there is no plan to support it.