mongoid presistance

lib/aasm/persistence/mongoid_persistence.rb

@@ -0,0 +1,247 @@
+module AASM
+  module Persistence
+    module MongoidPersistence
+      # This method:
+      #
+      # * extends the model with ClassMethods
+      # * includes InstanceMethods
+      #
+      # Unless the corresponding methods are already defined, it includes
+      # * ReadState
+      # * WriteState
+      # * WriteStateWithoutPersistence
+      #
+      # Adds
+      #
+      #   before_validation :aasm_ensure_initial_state
+      #
+      # As a result, it doesn't matter when you define your methods - the following 2 are equivalent
+      #
+      #   class Foo
+      #     include Mongoid::Document
+      #     def aasm_write_state(state)
+      #       "bar"
+      #     end
+      #     include AASM
+      #   end
+      #
+      #   class Foo
+      #     include Mongoid::Document
+      #     include AASM
+      #     def aasm_write_state(state)
+      #       "bar"
+      #     end
+      #   end
+      #
+      def self.included(base)
+        base.extend AASM::Persistence::MongoidPersistence::ClassMethods
+        base.send(:include, AASM::Persistence::MongoidPersistence::InstanceMethods)
+        base.send(:include, AASM::Persistence::MongoidPersistence::ReadState) unless base.method_defined?(:aasm_read_state)
+        base.send(:include, AASM::Persistence::MongoidPersistence::WriteState) unless base.method_defined?(:aasm_write_state)
+        base.send(:include, AASM::Persistence::MongoidPersistence::WriteStateWithoutPersistence) unless base.method_defined?(:aasm_write_state_without_persistence)
+
+        # if base.respond_to?(:named_scope)
+        #   base.extend(AASM::Persistence::MongoidPersistence::NamedScopeMethods)
+        # 
+        #   base.class_eval do
+        #     class << self
+        #       unless method_defined?(:aasm_state_without_named_scope)
+        #         alias_method :aasm_state_without_named_scope, :aasm_state
+        #         alias_method :aasm_state, :aasm_state_with_named_scope
+        #       end
+        #     end
+        #   end
+        # end
+
+        # Mongoid's Validatable gem dependency goes not have a before_validation_on_xxx hook yet.
+        # base.before_validation_on_create :aasm_ensure_initial_state
+        base.before_validation :aasm_ensure_initial_state
+      end
+
+      module ClassMethods
+        # Maps to the aasm_column in the database.  Deafults to "aasm_state".  You can write:
+        #
+        #   class Foo
+        #     include Mongoid::Document
+        #     include AASM
+        #     field :aasm_state
+        #   end
+        #
+        # OR:
+        #
+        #   class Foo
+        #     include Mongoid::Document
+        #     include AASM
+        #     field :status
+        #     aasm_column :status
+        #   end
+        #
+        # This method is both a getter and a setter
+        def aasm_column(column_name=nil)
+          if column_name
+            AASM::StateMachine[self].config.column = column_name.to_sym
+            # @aasm_column = column_name.to_sym
+          else
+            AASM::StateMachine[self].config.column ||= :aasm_state
+            # @aasm_column ||= :aasm_state
+          end
+          # @aasm_column
+          AASM::StateMachine[self].config.column
+        end
+
+        # def find_in_state(number, state, *args)
+        #   with_state_scope state do
+        #     find(number, *args)
+        #   end
+        # end
+        # 
+        # def count_in_state(state, *args)
+        #   with_state_scope state do
+        #     count(*args)
+        #   end
+        # end
+        # 
+        # def calculate_in_state(state, *args)
+        #   with_state_scope state do
+        #     calculate(*args)
+        #   end
+        # end
+
+        protected
+        def with_state_scope(state)
+          with_scope :find => {:conditions => ["#{table_name}.#{aasm_column} = ?", state.to_s]} do
+            yield if block_given?
+          end
+        end
+      end
+
+      module InstanceMethods
+
+        # Returns the current aasm_state of the object.  Respects reload and
+        # any changes made to the aasm_state field directly
+        #
+        # Internally just calls <tt>aasm_read_state</tt>
+        #
+        #   foo = Foo.find(1)
+        #   foo.aasm_current_state # => :pending
+        #   foo.aasm_state = "opened"
+        #   foo.aasm_current_state # => :opened
+        #   foo.close # => calls aasm_write_state_without_persistence
+        #   foo.aasm_current_state # => :closed
+        #   foo.reload
+        #   foo.aasm_current_state # => :pending
+        #
+        def aasm_current_state
+          @current_state = aasm_read_state
+        end
+
+        private
+
+        # Ensures that if the aasm_state column is nil and the record is new
+        # that the initial state gets populated before validation on create
+        #
+        #   foo = Foo.new
+        #   foo.aasm_state # => nil
+        #   foo.valid?
+        #   foo.aasm_state # => "open" (where :open is the initial state)
+        #
+        #
+        #   foo = Foo.find(:first)
+        #   foo.aasm_state # => 1
+        #   foo.aasm_state = nil
+        #   foo.valid?
+        #   foo.aasm_state # => nil
+        #
+        def aasm_ensure_initial_state
+          send("#{self.class.aasm_column}=", self.aasm_enter_initial_state.to_s) if send(self.class.aasm_column).blank?
+        end
+
+      end
+
+      module WriteStateWithoutPersistence
+        # Writes <tt>state</tt> to the state column, but does not persist it to the database
+        #
+        #   foo = Foo.find(1)
+        #   foo.aasm_current_state # => :opened
+        #   foo.close
+        #   foo.aasm_current_state # => :closed
+        #   Foo.find(1).aasm_current_state # => :opened
+        #   foo.save
+        #   foo.aasm_current_state # => :closed
+        #   Foo.find(1).aasm_current_state # => :closed
+        #
+        # NOTE: intended to be called from an event
+        def aasm_write_state_without_persistence(state)
+          write_attribute(self.class.aasm_column, state.to_s)
+        end
+      end
+
+      module WriteState
+        # Writes <tt>state</tt> to the state column and persists it to the database
+        # using update_attribute (which bypasses validation)
+        #
+        #   foo = Foo.find(1)
+        #   foo.aasm_current_state # => :opened
+        #   foo.close!
+        #   foo.aasm_current_state # => :closed
+        #   Foo.find(1).aasm_current_state # => :closed
+        #
+        # NOTE: intended to be called from an event
+        def aasm_write_state(state)
+          old_value = read_attribute(self.class.aasm_column)
+          write_attribute(self.class.aasm_column, state.to_s)
+
+          unless self.save(false)
+            write_attribute(self.class.aasm_column, old_value)
+            return false
+          end
+
+          true
+        end
+      end
+
+      module ReadState
+
+        # Returns the value of the aasm_column - called from <tt>aasm_current_state</tt>
+        #
+        # If it's a new record, and the aasm state column is blank it returns the initial state:
+        #
+        #   class Foo
+        #     include Mongoid::Document
+        #     include AASM
+        #     aasm_column :status
+        #     aasm_state :opened
+        #     aasm_state :closed
+        #   end
+        #
+        #   foo = Foo.new
+        #   foo.current_state # => :opened
+        #   foo.close
+        #   foo.current_state # => :closed
+        #
+        #   foo = Foo.find(1)
+        #   foo.current_state # => :opened
+        #   foo.aasm_state = nil
+        #   foo.current_state # => nil
+        #
+        # NOTE: intended to be called from an event
+        #
+        # This allows for nil aasm states - be sure to add validation to your model
+        def aasm_read_state
+          if new_record?
+            send(self.class.aasm_column).blank? ? aasm_determine_state_name(self.class.aasm_initial_state) : send(self.class.aasm_column).to_sym
+          else
+            send(self.class.aasm_column).nil? ? nil : send(self.class.aasm_column).to_sym
+          end
+        end
+      end
+
+      module NamedScopeMethods
+        def aasm_state_with_named_scope name, options = {}
+          aasm_state_without_named_scope name, options
+          self.named_scope name, :conditions => { "#{table_name}.#{self.aasm_column}" => name.to_s} unless self.respond_to?(name)
+        end
+      end
+    end
+  end
+end