List all states of a state machine.

README.rdoc

@@ -120,6 +120,17 @@ the name of the timestamp column.
     transiions :from => :exploded, :to => :rebuilt
   end
 
+== Listing all the available states
+
+You can easily get a listing of all available states:
+
+  Order.available_states # Uses the `default` state machine
+  # => [:pick_line_items, :picking_line_items]
+
+In case you have multiple state machines you can also pass the state machine name:
+
+  Order.available_states(:your_machine)
+
 = Documentation, Guides & Examples
 
 - {Online API Documentation}[http://rdoc.info/github/troessner/transitions/master/Transitions]

lib/transitions.rb

@@ -54,6 +54,10 @@ def state_machine(name = nil, options = {}, &block)
       block ? state_machines[name].update(options, &block) : state_machines[name]
     end
 
+    def available_states name = :default
+      state_machines[name].states.map(&:name).sort
+    end
+
     def define_state_query_method(state_name)
       name = "#{state_name}?"
       undef_method(name) if method_defined?(name)

test/test_available_states_listing.rb

@@ -0,0 +1,27 @@
+require "helper"
+
+class Bender
+  include Transitions
+
+  state_machine :default do
+    state :drinking
+    state :smoking
+    state :gambling
+  end
+
+  state_machine :maintenance do
+    state :wip
+    state :finished
+  end
+end
+
+class TestAvailableStatesListing < Test::Unit::TestCase
+  test 'available_states should return the states for the default state machine if no state machine is specified' do
+    assert_equal [:drinking, :gambling, :smoking], Bender.available_states
+  end
+
+  test 'available_states should return the states for a given state' do
+    assert_equal [:finished, :wip], Bender.available_states(:maintenance)
+    assert_equal [:drinking, :gambling, :smoking], Bender.available_states(:default)
+  end
+end