Creating a StateGate

step 1:

• include StateGate within the model class.

step 2:

• create the state-gate on the String attribute

step 3:

• pass a block defining the individual states with their allowed transitions.

simple example:

This example creates a minimal state-gate on the :status attribute of the Post class, allowing any state to transition to any other state without restriction.

class Post < ActiveRecord::Base
  include StateGate

  state_gate :status do
    state :draft
    state :pending
    state :published
    state :archived
  end
end

Post.new.status  #=> 'draft'

transition example:

This example creates a basic state-gate on the :status attribute of the Post class, defining the allowed transitions between states.

class Post < ActiveRecord::Base
  include StateGate

  state_gate :status do
    state :draft,     transitions_to: :pending
    state :pending,   transitions_to: [:published, :draft]
    state :published, transitions_to: :archived
    state :archived
  end
end

post = Post.new
post.status                 #=> 'draft'
post.status = :pending      #=> 'pending'
post.status = :draft        #=> 'draft'
post.status = :pending      #=> 'pending'
post.status = :published    #=> 'published'
post.status = 'archived'    #=> 'archived'
post.status = :published    #=> <ArgumentError>

sequential example:

This example creates a more complex state-gate with a prefix, a suffix, no scopes and one-way, looping, sequential transitions.

class UKTrafficLight < ActiveRecord::Base
  include StateGate

  state_gate :status do
    state :green
    state :yellow
    state :red
    state :red_and_yellow

    default :red

    prefix :traffic
    suffix :light

    no_scopes

    make_sequential :one_way, :loop
  end
end