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.
AASM has the following features:
-
States
-
Machines
-
Events
-
Transitions
New Callbacks
The only changes I’ve made are creating more callbacks with slightly more obvious semantics ;).
The callback chain & order on a successful event looks like:
oldstate:exit*
event:before
__find transition, if possible__
transition:on_transition*
newstate:enter*
oldstate:before_exit
newstate:before_enter
__update state__
oldstate:after_exit
oldstate:after_enter
event:after
event:success*
obj:aasm_event_fired*
(*) marks old callbacks
Note that the old callbacks haven’t been removed and still have their same semantics. All of this behavior was added without removing any old behavior.
Download
The latest AASM can currently be pulled from the git repository on github.
Installation
From GitHub hosted gems
% sudo gem sources -a http://gems.github.com # (you only need to do this once)
% sudo gem install dunedain289-aasm
Building your own gems
% rake gem
% sudo gem install pkg/aasm-2.1.gem
Simple Example
Here’s a quick example highlighting some of the features.
class Conversation
include AASM
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
Other Stuff
- Author
-
Scott Barron <scott at elitists dot net>
- License
-
Original code Copyright 2006, 2007, 2008 by Scott Barron. New changes Copyright 2009 by Scott Petersen. Released under an MIT-style license. See the LICENSE file included in the distribution.
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.