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
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_ 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 the gem with
gem install flojo
Alternatively, download lib/flojo.rb and copy it to your project's lib folder.
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.
baby.wf_feed #Will not trigger a save. baby.wf_feed! #Will trigger a save.
Copyright (c) 2010 Joey Adarkwah