Introduction

Statelogic is a yet another take on state management for your models. It’s tailored specially for ActiveRecord and is different from other frameworks in that it has its main goal in scoping validation rules and callbacks depending on the model’s state to emphasis actual model state consistency over merely formal… whatever…

Features

• State transitions validation.

• State-scoped validations.

• State-scoped lifecycle callbacks (before|after_save, etc)

• ???????

• PROFIT!!!11

Installation

gem install omg-statelogic --source http://gems.github.com

Installable as a plugin too.

Docs

rdoc.info/projects/omg/statelogic

Bugs & such

Please report via Github issue tracking.

Example

class Order < ActiveRecord::Base
  ...
  statelogic :attribute => :state do # +:state+ is the default value, may be omitted
    # you get methods +unpaid?+ and +was_unpaid?+.
    # may be more than one initial state.
    initial_state 'unpaid' do
      transitions_to 'ready', 'suspended' # won't let you change to wrong states
    end
    state 'ready' do # you get +ready?+, +was_ready?+
      transitions_to 'redeemed', 'suspended'
      validates_presence_of :txref # scoped validations
      before_save :prepare_for_plucking # scoped callbacks
    end
    state 'redeemed' do # likewise
      transitions_to 'suspended'
      validates_presence_of :txref, :redeemed_at, :facility_id # scoped validations
    end
    state 'suspended' do # you guess
      transitions_to 'unpaid', 'ready', 'redeemed'
      validate do |order|
        order.errors.add(:txref, :invalid) if order.txref && order.txref !~ /\AREF/
      end
    end
  end
  ...
end

order = Order.new
order.state = 'wtf'
order.txref = 'orly'
order.valid? # Please note that state transition checks are done during
             # the validation step as well, and the error is added to
             # the model's +errors+ collection on the state column and
             # will appear on your form. Standard ActiveRecord's error
             # message +:inclusion+ is used. Override it with Rails i18n
             # for something more specific if it's to be displayed to user.

See also

• github.com/omg/threadpool – Thread pool implementation

• github.com/omg/peanuts – Ruby <-> XML mapping

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Copyright © 2009 Igor Gunko, released under the MIT license