AASM - Ruby state machines
This package contains AASM, a library for adding finite state machines to Ruby classes.
AASM started as the acts_as_state_machine plugin but has evolved into a more generic library that no longer targets only ActiveRecord models.
Features
- States
- Machines
- Events
- Transitions
New Callbacks
The callback chain & order on a successful event looks like:
oldstate:exit*
event:before
__find transition, if possible__
transition:on_transition*
oldstate:before_exit
newstate:before_enter
newstate:enter*
__update state__
event:success*
oldstate:after_exit
newstate:after_enter
event:after
obj:aasm_event_fired*
(*) marks old callbacks
Download
The latest AASM can currently be pulled from the git repository on github.
Installation
From RubyGems.org
% gem install aasm
Building your own gems
% rake build
% sudo gem install pkg/aasm-x.y.z.gem
Simple Example
Here's a quick example highlighting some of the features.
class Conversation
include AASM
aasm_column :current_state # defaults to aasm_state
aasm_initial_state :unread
aasm_state :unread
aasm_state :read
aasm_state :closed
aasm_event :view do
transitions :to => :read, :from => [:unread]
end
aasm_event :close do
transitions :to => :closed, :from => [:read, :unread]
end
end
A Slightly More Complex Example
This example uses a few of the more complex features available.
class Relationship
include AASM
aasm_column :status
aasm_initial_state Proc.new { |relationship| relationship.strictly_for_fun? ? :intimate : :dating }
aasm_state :dating, :enter => :make_happy, :exit => :make_depressed
aasm_state :intimate, :enter => :make_very_happy, :exit => :never_speak_again
aasm_state :married, :enter => :give_up_intimacy, :exit => :buy_exotic_car_and_wear_a_combover
aasm_event :get_intimate do
transitions :to => :intimate, :from => [:dating], :guard => :drunk?
end
aasm_event :get_married do
transitions :to => :married, :from => [:dating, :intimate], :guard => :willing_to_give_up_manhood?
end
def strictly_for_fun?; end
def drunk?; end
def willing_to_give_up_manhood?; end
def make_happy; end
def make_depressed; end
def make_very_happy; end
def never_speak_again; end
def give_up_intimacy; end
def buy_exotic_car_and_wear_a_combover; end
end
Callbacks around events
class Relationship
include AASM
aasm_state :dating
aasm_state :married
aasm_event :get_married,
:before => :make_vows,
:after => :eat_wedding_cake do
transitions :to => :married, :from => [:dating]
end
end
Other Stuff
Author:: Scott Barron
Warranty
This software is provided "as is" and without any express or implied warranties, including, without limitation, the implied warranties of merchantibility and fitness for a particular purpose.