Refactor Date method to avoid redundant code

src/collective/cover/tiles/base.py

@@ -1,8 +1,6 @@
 # -*- coding: utf-8 -*-
-
 # Basic implementation taken from
 # http://davisagli.com/blog/using-tiles-to-provide-more-flexible-plone-layouts
-
 from AccessControl import Unauthorized
 from Acquisition import aq_base
 from Acquisition import aq_inner
@@ -53,6 +51,7 @@
 from zope.schema import getFieldsInOrder
 
 import logging
+import Missing
 
 logger = logging.getLogger(PROJECTNAME)
 
@@ -336,6 +335,28 @@ def isAllowedToEdit(self, user=None):
 
         return allowed
 
+    def Date(self, brain):
+        """Return the date of publication of the object referenced by
+        brain. If the object has not been published yet, return its
+        modification date. If the object is an Event, then return the
+        start date.
+
+        :param brain: [required] brain of the cataloged object
+            referenced in the tile
+        :type brain: AbstractCatalogBrain
+        :returns: the object's publication/modification date or the
+            event's start date in case of an Event-like object
+        :rtype: str or DateTime
+        """
+        calendar = api.portal.get_tool('portal_calendar')
+        # calendar_types lists all Event-like content types
+        if brain.portal_type not in calendar.calendar_types:
+            return brain.Date
+        else:
+            # an Event must have a start date
+            assert brain.start is not Missing.Value
+            return brain.start
+
     @property
     def has_image(self):
         return self.data.get('image', None) is not None

src/collective/cover/tiles/basic.py

@@ -14,8 +14,6 @@
 from zope import schema
 from zope.interface import implements
 
-import Missing
-
 
 class IBasicTile(IPersistentCoverTile):
 
@@ -77,23 +75,9 @@ def brain(self):
         return result[0] if result else None
 
     def Date(self):
-        """Return the date of publication of the object; if it has not been
-        published yet, it will return its modification date. If the object is
-        an Event, then return the start date.
-
-        :returns: the object's publication/modification date or the event's
-                  start date in case of an Event-like object
-        """
-        # brain is None if the tile was populated by editing it
+        # self.brain is None when the tile was populated by editing it
         if self.brain is not None:
-            calendar = api.portal.get_tool('portal_calendar')
-            # calendar_types lists all Event-like content types
-            if self.brain.portal_type not in calendar.calendar_types:
-                return self.brain.Date
-            else:
-                # Events must have a start date
-                assert self.brain.start is not Missing.Value
-                return self.brain.start
+            return super(BasicTile, self).Date(self.brain)
 
     def is_empty(self):
         return self.brain is None and \

src/collective/cover/tiles/collection.py

@@ -3,7 +3,6 @@
 from collective.cover.tiles.base import IPersistentCoverTile
 from collective.cover.tiles.base import PersistentCoverTile
 from collective.cover.tiles.configuration_view import IDefaultConfigureForm
-from plone import api
 from plone.app.uuid.utils import uuidToObject
 from plone.directives import form
 from plone.memoize import view
@@ -18,8 +17,6 @@
 from zope.interface import implements
 from zope.schema import getFieldsInOrder
 
-import Missing
-
 
 class ICollectionTile(IPersistentCoverTile):
 
@@ -127,25 +124,6 @@ def is_empty(self):
         return self.data.get('uuid', None) is None or \
             uuidToObject(self.data.get('uuid')) is None
 
-    def Date(self, brain):
-        """Return the date of publication of the object; if it has not been
-        published yet, it will return its modification date. If the object is
-        an Event, then return the start date.
-
-        :param brain: [required]
-        :type brain: catalog brain
-        :returns: the object's publication/modification date or the event's
-                  start date in case of an Event-like object
-        """
-        calendar = api.portal.get_tool('portal_calendar')
-        # calendar_types lists all Event-like content types
-        if brain.portal_type not in calendar.calendar_types:
-            return brain.Date
-        else:
-            # Events must have a start date
-            assert brain.start is not Missing.Value
-            return brain.start
-
     def populate_with_object(self, obj):
         super(CollectionTile, self).populate_with_object(obj)  # check permission
 

src/collective/cover/tiles/list.py

@@ -25,7 +25,6 @@
 from zope.schema import getFieldsInOrder
 
 import logging
-import Missing
 
 logger = logging.getLogger(PROJECTNAME)
 
@@ -141,15 +140,6 @@ def is_empty(self):
         return self.results() == []
 
     def Date(self, obj):
-        """Return the date of publication of the object; if it has not been
-        published yet, it will return its modification date. If the object is
-        an Event, then return the start date.
-
-        :param obj: [required]
-        :type obj: AT or DX-based content type object
-        :returns: the object's publication/modification date or the event's
-                  start date in case of an Event-like object
-        """
         # XXX: different from Collection tile, List tile returns objects
         #      instead of brains in its `results` function. I think we
         #      were looking for some performace gains there but in this
@@ -162,16 +152,7 @@ def Date(self, obj):
         catalog = api.portal.get_tool('portal_catalog')
         brain = catalog(UID=self.get_uid(obj))
         assert len(brain) == 1
-        brain = brain[0]
-
-        calendar = api.portal.get_tool('portal_calendar')
-        # calendar_types lists all Event-like content types
-        if brain.portal_type not in calendar.calendar_types:
-            return brain.Date
-        else:
-            # Events must have a start date
-            assert brain.start is not Missing.Value
-            return brain.start
+        return super(ListTile, self).Date(brain[0])
 
     # TODO: get rid of this by replacing it with the 'count' field
     def set_limit(self):