Module: DataMapper::Is::PersistentStateMachine

Defined in:
lib/dm-is-persistent_state_machine/is/persistent_state_machine.rb

Defined Under Namespace

Modules: ClassMethods, InstanceMethods Classes: DmIsPersistentStateMachineException

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

fired when plugin gets included into Resource



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# File 'lib/dm-is-persistent_state_machine/is/persistent_state_machine.rb', line 69

def self.included(base)
  
end

Instance Method Details

#is_persistent_state_machine ⇒ Object

Methods that should be included in DataMapper::Model. Normally this should just be your generator, so that the namespace does not get cluttered. ClassMethods and InstanceMethods gets added in the specific resources when you fire is :example



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# File 'lib/dm-is-persistent_state_machine/is/persistent_state_machine.rb', line 80

def is_persistent_state_machine
  DataMapper.logger.info "registering persistent state machine..."
  
  # Add class-methods
  extend DataMapper::Is::PersistentStateMachine::ClassMethods
  extend Forwardable
  # Add instance-methods
  include DataMapper::Is::PersistentStateMachine::InstanceMethods
  
  target_model_name = self.name.snake_case
  
  # target object must have a status associated
  property :state_id, Integer, :required => true, :min => 1
  belongs_to :state
  
  has n, Extlib::Inflection.pluralize(target_model_name+"StateChange").snake_case.to_sym, :constraint => :destroy!
  
  # generate a FooState class that is derived from State        
  state_model = Object.full_const_set(self.to_s+"State", Class.new(State))
  # generate a FooStateEvent class that is derived from StateEvent
  event_model = Object.full_const_set(self.to_s+"StateEvent", Class.new(StateEvent))

  state_change_model = Class.new do
    include DataMapper::Resource

    property :id, ::DataMapper::Types::Serial

    property :from_id, Integer,   :required => true, :min => 1
    property :to_id, Integer,     :required => true, :min => 1
    property :user_id, Integer,   :required => true, :min => 1
    property Extlib::Inflection.foreign_key(target_model_name).to_sym, Integer, :required => true, :min => 1
    property :created_at, DateTime

    # associations
    belongs_to :user
    belongs_to :from, "State"
    belongs_to :to,   "State"
    belongs_to target_model_name.to_sym
  end
  
  state_change_model = Object.full_const_set(self.to_s+"StateChange",state_change_model)
  
  self_cached = self
  
  after :save do
    if (@prev_state && @prev_state != state)
      @state_change = state_change_model.create(:from => @prev_state, :to => state, :created_at => DateTime.now, :user => @updating_user, Extlib::Inflection.foreign_key(target_model_name).to_sym => self.id)
      @prev_state = nil # clean up cache
      @user = nil
    end
  end

  # define delegators
  def_delegators :@state, :events        
end