Add a marker interface to objects

Apply it to objects that are reported to have stop words,
and only the ones that are within the scope of a contentrule that
has the ``collective.contentalerts.TextAlert`` condition on it.

This is the building block for a view to show all objects that have
stop words on it.

src/collective/contentalerts/contentrules.py

@@ -2,14 +2,17 @@
 from OFS.SimpleItem import SimpleItem
 from collective.contentalerts import _
 from collective.contentalerts.interfaces import IAlert
+from collective.contentalerts.interfaces import IHasStopWords
 from collective.contentalerts.interfaces import ITextAlertCondition
 from plone.app.contentrules.browser.formhelper import AddForm
 from plone.app.contentrules.browser.formhelper import EditForm
 from plone.contentrules.rule.interfaces import IRuleElementData
 from plone.stringinterp.adapters import BaseSubstitution
 from zope.component import getUtility
 from zope.formlib import form
+from zope.interface import alsoProvides
 from zope.interface import implementer
+from zope.interface import noLongerProvides
 
 
 class TextAlertConditionExecutor(object):
@@ -45,7 +48,20 @@ def __call__(self):
 
         alert_utility = getUtility(IAlert)
 
-        return alert_utility.has_stop_words(text, stop_words=stop_words)
+        ret_value = alert_utility.has_stop_words(text, stop_words=stop_words)
+        self._apply_marker_interface(ret_value)
+        return ret_value
+
+    def _apply_marker_interface(self, has_stop_words):
+        if getattr(self.event, 'comment', None):
+            obj = self.event.comment
+        else:
+            obj = self.event.object
+
+        if has_stop_words:
+            alsoProvides(obj, IHasStopWords)
+        elif IHasStopWords.providedBy(obj):
+            noLongerProvides(obj, IHasStopWords)
 
 
 @implementer(ITextAlertCondition, IRuleElementData)

src/collective/contentalerts/interfaces.py

@@ -72,3 +72,7 @@ class ITextAlertCondition(Interface):
         ),
         required=False,
     )
+
+
+class IHasStopWords(Interface):
+    """Marker interface attached to objects that have stop words."""

src/collective/contentalerts/tests/test_contentrules.py

@@ -2,6 +2,7 @@
 from Testing.ZopeTestCase.utils import setupCoreSessions
 from collective.contentalerts.contentrules import TextAlertCondition
 from collective.contentalerts.contentrules import TextAlertConditionEditForm
+from collective.contentalerts.interfaces import IHasStopWords
 from collective.contentalerts.interfaces import IStopWords
 from collective.contentalerts.testing import COLLECTIVE_CONTENTALERTS_DEXTERITY_INTEGRATION_TESTING  # noqa
 from collective.contentalerts.testing import COLLECTIVE_CONTENTALERTS_INTEGRATION_TESTING  # noqa
@@ -312,6 +313,64 @@ def test_stop_words_not_in_request(self):
         executable()
         self.assertIsNone(self.request.get('stop_words'))
 
+    def test_has_stop_words_add_interface_comment(self):
+        comment = self._add_comment('one alert')
+        condition = TextAlertCondition()
+        condition.stop_words = u'one alert\nanother alert'
+
+        executable = getMultiAdapter(
+            (self.portal, condition, CommentDummyEvent(comment)),
+            IExecutable
+        )
+        executable()
+        self.assertTrue(IHasStopWords.providedBy(comment))
+
+    def test_has_stop_words_add_interface_document(self):
+        name = self.portal.invokeFactory(
+            id='doc2',
+            title='Document 1',
+            type_name='Document'
+        )
+        document = self.portal[name]
+        document.setText('this gives one alert')
+        condition = TextAlertCondition()
+        condition.stop_words = u'one alert\nanother alert'
+
+        executable = getMultiAdapter(
+            (self.portal, condition, ContentTypeDummyEvent(document)),
+            IExecutable
+        )
+        executable()
+        self.assertTrue(IHasStopWords.providedBy(document))
+
+    def test_no_stop_words_no_interface(self):
+        comment = self._add_comment('no alert')
+        condition = TextAlertCondition()
+        condition.stop_words = u'one alert\nanother alert'
+
+        executable = getMultiAdapter(
+            (self.portal, condition, CommentDummyEvent(comment)),
+            IExecutable
+        )
+        executable()
+        self.assertFalse(IHasStopWords.providedBy(comment))
+
+    def test_add_and_remove_interface(self):
+        comment = self._add_comment('one alert')
+        condition = TextAlertCondition()
+        condition.stop_words = u'one alert\nanother alert'
+
+        # adds the marker interface
+        executable = getMultiAdapter(
+            (self.portal, condition, CommentDummyEvent(comment)),
+            IExecutable
+        )
+        executable()
+
+        comment.text = 'no longer creating an alert'
+        executable()
+        self.assertFalse(IHasStopWords.providedBy(comment))
+
 
 class DexterityTextAlertConditionTestCase(unittest.TestCase):
     layer = COLLECTIVE_CONTENTALERTS_DEXTERITY_INTEGRATION_TESTING