Add simple support for ActiveModel's StateMachine for ActiveRecord

2 files changed, 25 insertions, 0 deletions

diff --git a/activerecord/lib/active_record.rb b/activerecord/lib/active_record.rb
index 5e9ce0600a..68b0251982 100644
--- a/activerecord/lib/active_record.rb
+++ b/activerecord/lib/active_record.rb
@@ -65,6 +65,7 @@ module ActiveRecord
   autoload :SchemaDumper, 'active_record/schema_dumper'
   autoload :Serialization, 'active_record/serialization'
   autoload :SessionStore, 'active_record/session_store'
+  autoload :StateMachine, 'active_record/state_machine'
   autoload :TestCase, 'active_record/test_case'
   autoload :Timestamp, 'active_record/timestamp'
   autoload :Transactions, 'active_record/transactions'
diff --git a/activerecord/lib/active_record/state_machine.rb b/activerecord/lib/active_record/state_machine.rb
new file mode 100644
index 0000000000..aebd03344a
--- /dev/null
+++ b/activerecord/lib/active_record/state_machine.rb
@@ -0,0 +1,24 @@
+module ActiveRecord
+  module StateMachine #:nodoc:
+    extend ActiveSupport::Concern
+    include ActiveModel::StateMachine
+
+    included do
+      before_validation :set_initial_state
+      validates_presence_of :state
+    end
+
+    protected
+      def write_state(state_machine, state)
+        update_attributes! :state => state.to_s
+      end
+
+      def read_state(state_machine)
+        self.state.to_sym
+      end
+
+      def set_initial_state
+        self.state ||= self.class.state_machine.initial_state.to_s
+      end
+  end
+end