Flojo
Flojo is a simple ActiveRecord aware state machine module, but it will also work with any plain old ruby object.
When used within an ActiveRecord subclass, flojo events can automatically save a record after a transition.
After including the module in your class and configuring it with an event
, and a state
,
you can interact with instances of that class using the dynamically generated methods of the following form:
object.wf_event #Triggers event and invokes any applicable transitions
object.wf_event! #Behaves just like object.wf_event but will also persist object.
object.wf_state? #Returns true if the current workflow state is _state_.
object.wf_current_state #Returns the objects current state.
To avoid method name collisions with your classes, Flojo methods are usually prefixed with wf_
.
The wf_
is also handy when you need to interact with your objects in irb. Just type wf_
and tab...
See test.rb, test_active_record.rb and test_helper.rb for concrete examples.
Install
Install the gem with
gem install flojo
Alternatively, download lib/flojo.rb and copy it to your project's lib folder.
Usage
require 'flojo'
class Baby
# Include the module
include Flojo
# configure the states. The first element represents the initial state
workflow_states [:asleep, :crying, :pooping, :chilling, :puking]
# configure your transitions. Using: transition :begin_state, :end_state
event :feed do
transition :crying, :chilling
transition :chilling, :pooping
end
event :rock do
transition :crying, :chilling
transition :chilling, :asleep
transition :asleep, :pooping
end
event :burp do
transition :crying, :chilling
transition :chilling, :puking
end
event :wake do
transition :asleep, :crying
end
event :spank do
# :any is a wildcard state and is only valid as a begin state.
transition :any, :crying
end
# event, enter state and exit state callbacks should take the following forms:
# wf_on_event, wf_on_enter_state and wf_on_exit_state and are only called if they are defined
def wf_on_spank
puts "Never spank a baby! Somebody dial 911!"
end
def wf_on_enter_chilling
puts "drool and fart"
end
def wf_on_exit_asleep
puts "waaaaah waaaaah waaaaaah"
end
# called only after an event yields a transition.
def wf_after_transition
puts "Send a tweet baby is alive and kicking"
end
# called only after an event triggers a save.
def wf_after_save
puts "Send a tweet saying baby was saved"
end
end
baby = Baby.new
baby.wf_asleep?
baby.wf_wake
baby.wf_current_state #Should return :awake
ActiveRecord specific details
If you want the current workflow state persisted, your table needs to have a string column named wf_state. If your table has a wf_last_event column, that column will store the most recent event triggered on the object. The module will still work if the wf_state is absent but the workflow state will be transient. When used within an ActiveRecord subclass, the "!" versions of the wf_event methods will - trigger a record save immediately after transition.
eg:
baby.wf_feed #Will not trigger a save.
baby.wf_feed! #Will trigger a save.
Copyright
Copyright (c) 2010 Joey Adarkwah