1 files changed, 62 insertions, 1 deletions
diff --git a/src/mailman/interfaces/workflow.py b/src/mailman/interfaces/workflows.py
index 5b3582b58..b110a481e 100644
--- a/src/mailman/interfaces/workflow.py
+++ b/src/mailman/interfaces/workflows.py
@@ -15,7 +15,7 @@
 # You should have received a copy of the GNU General Public License along with
 # GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
 
-"""Interfaces describing the state of a workflow."""
+"""Interfaces describing the a workflow, it's state and it's state manager."""
 
 from public import public
 from zope.interface import Attribute, Interface
@@ -65,3 +65,64 @@ class IWorkflowStateManager(Interface):
         """
 
     count = Attribute('The number of saved workflows in the database.')
+
+
+@public
+class IWorkflow(Interface):
+    """A workflow."""
+
+    name = Attribute('The name of the workflow, must be unique.')
+    description = Attribute('A brief description of the workflow.')
+    initial_state = Attribute('The state in which the workflow starts.')
+    save_attributes = Attribute('The sequence of attributes of the workflow, '
+                                'which are saved.')
+
+    def __iter__():
+        """Return an iterator over the steps."""
+
+    def __next__():
+        """Run the next step from the queue.
+
+        :return: The result of the step run.
+        """
+
+    def push(step):
+        """Push a step to this workflows queue."""
+
+    def run_thru(stop_after):
+        """Run the state machine through and including the given step.
+
+        :param stop_after: Name of method, sans prefix to run the
+            state machine through.  In other words, the state machine runs
+            until the named method completes.
+        """
+
+    def run_until(stop_before):
+        """Run the state machine until (not including) the given step.
+
+        :param stop_before: Name of method, sans prefix that the
+            state machine is run until the method is reached.  Unlike
+            `run_thru()` the named method is not run.
+        """
+
+    def save():
+        """Save the workflow in it's current state.
+
+        Needs to have the `token` attribute set.
+        """
+
+    def restore():
+        """Restore the workflow from the database.
+
+        Needs to have the `token` attribute set.
+        """
+
+
+@public
+class ISubscriptionWorkflow(IWorkflow):
+    """A workflow used for subscription."""
+
+
+@public
+class IUnsubscriptionWorkflow(IWorkflow):
+    """A workflow used for unsubscription."""