Statum

Finite state machine for your objects

Installation

Add this line to your application's Gemfile:

gem 'statum'

And then execute:

$ bundle

Or install it yourself as:

$ gem install statum

Usage

Basic usage

Statum provides a DSL for defining state machine for your class

class Car
  include Statum

  attr_accessor :state

  statum :state, initial: :idle do
    state :idle
    state :riding

    event :ride, idle: :riding
  end
end

Then Car object will receive following methods:

car = Car.new
car.idle? # => true
car.riding? # => false
car.ride! # changes idle state to riding

Hooks

You can be able to execute some procs before and after event will be fired

class Car
  include Statum

  attr_accessor :state, :started

  statum :state, initial: :idle do
    state :idle
    state :riding

    event :ride, idle: :riding,
                 before: -> { self.started = true },
                 after: :stop_engine
  end

  def stop_engine
    self.started = false
  end
end

And then before state changes will be executed before proc, and after changing - after proc (in instance context).

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/nulldef/statum.

License

The gem is available as open source under the terms of the MIT License.