Use zope.interface decorator

This not only makes code more pleasent to read,
but also makes the code python 3 compatible
(while maintaining python 2 compatibility).

CHANGES.rst

@@ -14,7 +14,8 @@ New features:
 
 Bug fixes:
 
-- *add item here*
+- Use zope.interface decorator.
+  [gforcada]
 
 
 2.4.16 (2016-06-27)

plone/app/discussion/browser/captcha.py

@@ -18,10 +18,10 @@ from zope.interface import Interface
 from zope.publisher.interfaces.browser import IDefaultBrowserLayer
 
 
+@interface.implementer(ICaptcha)
 class Captcha(Persistent):
     """Captcha input field.
     """
-    interface.implements(ICaptcha)
     adapts(Comment)
     captcha = u""
 

plone/app/discussion/browser/traversal.py

@@ -6,13 +6,14 @@ into an actual comment object.
 from plone.app.discussion.interfaces import IConversation
 from zope.component import adapts
 from zope.component import queryAdapter
-from zope.interface import implements
+from zope.interface import implementer
 from zope.interface import Interface
 from zope.publisher.interfaces.browser import IBrowserRequest
 from zope.traversing.interfaces import ITraversable
 from zope.traversing.interfaces import TraversalError
 
 
+@implementer(ITraversable)
 class ConversationNamespace(object):
     """Allow traversal into a conversation via a ++conversation++name
     namespace. The name is the name of an adapter from context to
@@ -20,8 +21,6 @@ class ConversationNamespace(object):
     (unnamed) adapter. This is to work around a bug in OFS.Traversable which
     does not allow traversal to namespaces with an empty string name.
     """
-
-    implements(ITraversable)
     adapts(Interface, IBrowserRequest)
 
     def __init__(self, context, request=None):

plone/app/discussion/browser/validator.py

@@ -11,7 +11,7 @@ from z3c.form.interfaces import IValidator
 from zope.component import adapts
 from zope.component import getMultiAdapter
 from zope.component import queryUtility
-from zope.interface import implements
+from zope.interface import implementer
 from zope.interface import Interface
 from zope.schema.interfaces import IField
 
@@ -32,8 +32,8 @@ except ImportError:
     pass
 
 
+@implementer(IValidator)
 class CaptchaValidator(validator.SimpleFieldValidator):
-    implements(IValidator)
     adapts(Interface, IDiscussionLayer, Interface, IField, Interface)
     #       Object, Request, Form, Field, Widget,
     # We adapt the CaptchaValidator class to all form fields (IField)

plone/app/discussion/comment.py

@@ -35,7 +35,7 @@ from zope.component.factory import Factory
 from zope.event import notify
 from zope.i18n import translate
 from zope.i18nmessageid import Message
-from zope.interface import implements
+from zope.interface import implementer
 
 import logging
 
@@ -65,6 +65,7 @@ MAIL_NOTIFICATION_MESSAGE_MODERATOR = _(
 logger = logging.getLogger('plone.app.discussion')
 
 
+@implementer(IComment)
 class Comment(CatalogAware, WorkflowAware, DynamicType, Traversable,
               RoleManager, Owned, Implicit, Persistent):
     """A comment.
@@ -73,8 +74,6 @@ class Comment(CatalogAware, WorkflowAware, DynamicType, Traversable,
     number of standard methods instead of subclassing, to have total control
     over what goes into the object.
     """
-
-    implements(IComment)
     security = ClassSecurityInfo()
 
     meta_type = portal_type = 'Discussion Item'

plone/app/discussion/conversation.py

@@ -34,7 +34,6 @@ from zope.component import adapts
 from zope.container.contained import ContainerModifiedEvent
 from zope.event import notify
 from zope.interface import implementer
-from zope.interface import implements
 from zope.lifecycleevent import ObjectAddedEvent
 from zope.lifecycleevent import ObjectCreatedEvent
 from zope.lifecycleevent import ObjectRemovedEvent
@@ -42,6 +41,7 @@ from zope.lifecycleevent import ObjectRemovedEvent
 import time
 
 
+@implementer(IConversation, IHideFromBreadcrumbs)
 class Conversation(Traversable, Persistent, Explicit):
     """A conversation is a container for all comments on a content object.
 
@@ -49,8 +49,6 @@ class Conversation(Traversable, Persistent, Explicit):
     comment lookup.
     """
 
-    implements(IConversation, IHideFromBreadcrumbs)
-
     __allow_access_to_unprotected_subobjects__ = True
 
     def __init__(self, id='++conversation++default'):
@@ -327,13 +325,12 @@ else:
         return conversationAdapterFactory(content)
 
 
+@implementer(IReplies)
 class ConversationReplies(object):
     """An IReplies adapter for conversations.
 
     This makes it easy to work with top-level comments.
     """
-
-    implements(IReplies)
     adapts(Conversation)  # relies on implementation details
 
     def __init__(self, context):
@@ -404,14 +401,13 @@ class ConversationReplies(object):
         return self.conversation._children.get(self.comment_id, LLSet())
 
 
+@implementer(IReplies)
 class CommentReplies(ConversationReplies):
     """An IReplies adapter for comments.
 
     This makes it easy to work with replies to specific comments.
     """
 
-    implements(IReplies)
-
     # depends on implementation details of conversation
     # most likely, anyone writing a different type of Conversation will also
     # have a different type of Comment

plone/app/discussion/events.py

@@ -6,13 +6,13 @@ from plone.app.discussion.interfaces import ICommentRemovedEvent
 from plone.app.discussion.interfaces import IDiscussionEvent
 from plone.app.discussion.interfaces import IReplyAddedEvent
 from plone.app.discussion.interfaces import IReplyRemovedEvent
-from zope.interface import implements
+from zope.interface import implementer
 
 
+@implementer(IDiscussionEvent)
 class DiscussionEvent(object):
     """ Custom event
     """
-    implements(IDiscussionEvent)
 
     def __init__(self, context, comment, **kwargs):
         self.object = context
@@ -26,25 +26,25 @@ class DiscussionEvent(object):
         request.set('event', self)
 
 
+@implementer(ICommentAddedEvent)
 class CommentAddedEvent(DiscussionEvent):
     """ Event to be triggered when a Comment is added
     """
-    implements(ICommentAddedEvent)
 
 
+@implementer(ICommentRemovedEvent)
 class CommentRemovedEvent(DiscussionEvent):
     """ Event to be triggered when a Comment is removed
     """
-    implements(ICommentRemovedEvent)
 
 
+@implementer(IReplyAddedEvent)
 class ReplyAddedEvent(DiscussionEvent):
     """ Event to be triggered when a Comment reply is added
     """
-    implements(IReplyAddedEvent)
 
 
+@implementer(IReplyRemovedEvent)
 class ReplyRemovedEvent(DiscussionEvent):
     """ Event to be triggered when a Comment reply is removed
     """
-    implements(IReplyRemovedEvent)

plone/app/discussion/tool.py

@@ -14,10 +14,9 @@ from zope import interface
 from zope.component import queryUtility
 
 
+@interface.implementer(ICommentingTool)
 class CommentingTool(UniqueObject, SimpleItem):
 
-    interface.implements(ICommentingTool)
-
     meta_type = 'plone.app.discussion tool'
     id = 'portal_discussion'