Stateful 🦜
The easiest state machine in Swift.
Stateful is a minimalistic, thread-safe, non-boilerplate and super easy to use state machine in Swift.
Example
- define the events and statuses you need. E.g.:
enum EventType {
case start
case pause
}
enum StateType {
case idle
case started
}
- create a state machine with the initial state (you might want to retain it in a property)
let stateMachine = StateMachine<StateType, EventType>(initialState: .idle)
StateMachine
will use the main queue to execute the transition pre and post blocks but you can optionally provide a custom one.
let dispatchQueue = DispatchQueue(label: "com.albertodebortoli.someSerialCallbackQueue")
let stateMachine = StateMachine<StateType, EventType>(initialState: StateType.idle, callbackQueue: dispatchQueue)
- create transitions and add them to the state machine (the state machine will automatically recognize the new statuses)
let t1 = Transition<StateType, EventType>(with: .start,
from: .idle,
to: .started)
let t2 = Transition<StateType, EventType>(with: .pause,
from: .started,
to: .idle,
preBlock: {
print("Going to move from \(StateType.started) to \(StateType.idle)!")
}, postBlock: {
print("Just moved from \(StateType.started) to \(StateType.idle)!")
})
stateMachine.add(transition: t1)
stateMachine.add(transition: t2)
- process events like so
stateMachine.process(event: .start)
stateMachine.process(event: .pause, callback: { result in
switch result {
case .success:
print("Event 'pause' was processed")
case .failure:
print("Event 'pause' cannot currently be processed.")
}
})
Logging
You can optionally enable logging to print extra state change information on the console
stateMachine.enableLogging = true
Example:
[Stateful 🦜]: Processing event 'start' from 'idle'
[Stateful 🦜]: Processed pre condition for event 'start' from 'idle' to 'started'
[Stateful 🦜]: Processed state change from 'idle' to 'started'
[Stateful 🦜]: Processed post condition for event 'start' from 'idle' to 'started'
[Stateful 🦜]: Processing event 'stop' from 'started'
[Stateful 🦜]: Processed pre condition for event 'stop' from 'started' to 'idle'
[Stateful 🦜]: Processed state change from 'started' to 'idle'
[Stateful 🦜]: Processed post condition for event 'stop' from 'started' to 'idle'
Installation
Stateful is available through CocoaPods. To install it, simply add the following line to your Podfile:
pod 'Stateful'
Author
Alberto De Bortoli, [email protected]
License
Stateful is available under the MIT license. See the LICENSE file for more info.