================
Container events
================

Zope 3 container events are used to inform subscribers that an object is
about to be added/removed from a container, and also after it has been
done. This is used for bookkeeping and cleaning up in subobjects.

These events replace the old Zope 2 manage_afterAdd, manage_beforeDelete
and manage_afterClone methods.

All standard Zope containers will only call manage_afterAdd & co on
classes specified with the directive::

  <five:deprecatedManageAddDelete class="some.content.class"/>

Classes that don't have this directive but still have manage_afterAdd &
co methods will trigger a warning when they are called (and this is
strictly a compatibility call, behavior may not be strictly equivalent
to the original one).

Test setup
==========

A bit of setup for the tests. Because we'll test copy/paste, we need to
work inside a database::

  >>> import ZODB.tests.util
  >>> db = ZODB.tests.util.DB()
  >>> connection = db.open()
  >>> root = connection.root()

We'll use a few simple classes (defined in python code for picklability)
for our tests.

  >>> from Products.Five.tests.test_event import MyApp, MyContent
  >>> from Products.Five.tests.test_event import MyFolder, MyBTreeFolder
  >>> from Products.Five.tests.test_event import MyOrderedFolder

  >>> app = MyApp('')
  >>> root['app'] = app
  >>> folder = MyFolder('folder')
  >>> app._setObject('folder', folder) # doctest: +NORMALIZE_WHITESPACE
  old manage_afterAdd folder folder
  'folder'
  >>> folder = app.folder
  >>> btfolder = MyBTreeFolder('btfolder')
  >>> app._setObject('btfolder', btfolder) # doctest: +NORMALIZE_WHITESPACE
  old manage_afterAdd btfolder btfolder
  'btfolder'

To observe what object events are dispatched, we'll have some
subscribers print them. We'll actually do that for a specific interface,
not for (None, IObjectEvent), and register our subscribers before the
framework's ones, so ours will be called first. This has the effect that
printed events will be in their "natural" order::

  >>> from zope.component.interfaces import IObjectEvent, IRegistrationEvent
  >>> from zope.app.container.interfaces import IObjectMovedEvent
  >>> from zope.lifecycleevent.interfaces import IObjectCopiedEvent
  >>> from OFS.interfaces import IObjectWillBeMovedEvent
  >>> from OFS.interfaces import IObjectClonedEvent
  >>> from OFS.interfaces import IItem
  >>> def printObjectEvent(object, event):
  ...     print event.__class__.__name__, object.getId()
  >>> def printObjectEventExceptSome(object, event):
  ...     if (IObjectMovedEvent.providedBy(event) or
  ...         IObjectCopiedEvent.providedBy(event) or
  ...         IObjectWillBeMovedEvent.providedBy(event) or
  ...         IObjectClonedEvent.providedBy(event) or
  ...         IRegistrationEvent.providedBy(event)):
  ...         return
  ...     print event.__class__.__name__, object.getId()

  >>> from zope.component import provideHandler
  >>> provideHandler(printObjectEvent, (IItem, IObjectMovedEvent))
  >>> provideHandler(printObjectEvent, (IItem, IObjectCopiedEvent))
  >>> provideHandler(printObjectEvent, (IItem, IObjectWillBeMovedEvent))
  >>> provideHandler(printObjectEvent, (IItem, IObjectClonedEvent))
  >>> provideHandler(printObjectEventExceptSome, (None, IObjectEvent))

Finally we need to load the subscribers configuration::

  >>> import zope.component
  >>> import OFS.subscribers
  >>> zope.component.provideAdapter(OFS.subscribers.ObjectManagerSublocations)
  >>> zope.component.provideHandler(OFS.subscribers.dispatchObjectWillBeMovedEvent)
  >>> zope.component.provideHandler(OFS.subscribers.dispatchObjectMovedEvent)
  >>> zope.component.provideHandler(OFS.subscribers.dispatchObjectCopiedEvent)
  >>> zope.component.provideHandler(OFS.subscribers.dispatchObjectClonedEvent)

We need at least one fake deprecated method to tell the compatibility
framework that component architecture is initialized::

  >>> from Products.Five.eventconfigure import setDeprecatedManageAddDelete
  >>> class C(object): pass
  >>> setDeprecatedManageAddDelete(C)

Old class
=========

If we use an instance of an old class for which we haven't specified
anything, events are sent and the manage_afterAdd & co methods are
called, but with a deprecation warning::

  >>> sub = MyFolder('sub')
  >>> folder._setObject('sub', sub)
  ObjectWillBeAddedEvent sub
  ObjectAddedEvent sub
  old manage_afterAdd sub sub folder
  ContainerModifiedEvent folder
  'sub'
  >>> sub = folder.sub
  >>> ob = MyContent('dog')
  >>> sub._setObject('dog', ob)
  ObjectWillBeAddedEvent dog
  ObjectAddedEvent dog
  old manage_afterAdd dog dog sub
  ContainerModifiedEvent sub
  'dog'

And when we rename the subfolder, manage_beforeDelete is also called
bottom-up and events are sent::

  >>> folder.manage_renameObject('sub', 'marine')
  ObjectWillBeMovedEvent sub
  ObjectWillBeMovedEvent dog
  old manage_beforeDelete dog sub folder
  old manage_beforeDelete sub sub folder
  ObjectMovedEvent marine
  old manage_afterAdd marine marine folder
  ObjectMovedEvent dog
  old manage_afterAdd dog marine folder
  ContainerModifiedEvent folder

Same thing for clone::

  >>> res = folder.manage_clone(folder.marine, 'tank')
  ObjectCopiedEvent tank
  ObjectCopiedEvent dog
  ObjectWillBeAddedEvent tank
  ObjectWillBeAddedEvent dog
  ObjectAddedEvent tank
  old manage_afterAdd tank tank folder
  ObjectAddedEvent dog
  old manage_afterAdd dog tank folder
  ContainerModifiedEvent folder
  ObjectClonedEvent tank
  old manage_afterClone tank tank
  ObjectClonedEvent dog
  old manage_afterClone dog tank
  >>> res.getId()
  'tank'

Old class with deprecatedManageAddDelete
========================================

We specifiy that our class is deprecated (using zcml in real life)::

  >>> setDeprecatedManageAddDelete(MyContent)
  >>> setDeprecatedManageAddDelete(MyFolder)
  >>> setDeprecatedManageAddDelete(MyOrderedFolder)

Now some events are sent but the old manage_afterAdd method is also
called correctly::

  >>> ob = MyContent('lassie')
  >>> folder._setObject('lassie', ob)
  ObjectWillBeAddedEvent lassie
  ObjectAddedEvent lassie
  old manage_afterAdd lassie lassie folder
  ContainerModifiedEvent folder
  'lassie'

And when we delete the object, manage_beforeDelete is also called and
events are sent::

  >>> folder.manage_delObjects('lassie')
  ObjectWillBeRemovedEvent lassie
  old manage_beforeDelete lassie lassie folder
  ObjectRemovedEvent lassie
  ContainerModifiedEvent folder

The old behavior happens for a move or a copy, with events too.
For a move::

  >>> ob = MyContent('blueberry')
  >>> folder._setObject('blueberry', ob)
  ObjectWillBeAddedEvent blueberry
  ObjectAddedEvent blueberry
  old manage_afterAdd blueberry blueberry folder
  ContainerModifiedEvent folder
  'blueberry'
  >>> cp = folder.manage_cutObjects('blueberry')
  >>> folder.manage_pasteObjects(cp)
  ObjectWillBeMovedEvent blueberry
  old manage_beforeDelete blueberry blueberry folder
  ObjectMovedEvent blueberry
  old manage_afterAdd blueberry blueberry folder
  ContainerModifiedEvent folder
  [{'new_id': 'blueberry', 'id': 'blueberry'}]

Old behavior with events for a copy::

  >>> cp = folder.manage_copyObjects('blueberry')
  >>> folder.manage_pasteObjects(cp)
  ObjectCopiedEvent copy_of_blueberry
  ObjectWillBeAddedEvent copy_of_blueberry
  ObjectAddedEvent copy_of_blueberry
  old manage_afterAdd copy_of_blueberry copy_of_blueberry folder
  ContainerModifiedEvent folder
  ObjectClonedEvent copy_of_blueberry
  old manage_afterClone copy_of_blueberry copy_of_blueberry
  [{'new_id': 'copy_of_blueberry', 'id': 'blueberry'}]

Old behavior with events for a renaming::

  >>> folder.manage_renameObject('copy_of_blueberry', 'myrtille')
  ObjectWillBeMovedEvent copy_of_blueberry
  old manage_beforeDelete copy_of_blueberry copy_of_blueberry folder
  ObjectMovedEvent myrtille
  old manage_afterAdd myrtille myrtille folder
  ContainerModifiedEvent folder

Old behavior with events for a clone::

  >>> res = folder.manage_clone(folder.blueberry, 'strawberry')
  ObjectCopiedEvent strawberry
  ObjectWillBeAddedEvent strawberry
  ObjectAddedEvent strawberry
  old manage_afterAdd strawberry strawberry folder
  ContainerModifiedEvent folder
  ObjectClonedEvent strawberry
  old manage_afterClone strawberry strawberry
  >>> res.getId()
  'strawberry'

Events are also sent when we work with a BTreeFolder::

  >>> ob = MyContent('luckyluke')
  >>> btfolder._setObject('luckyluke', ob)
  ObjectWillBeAddedEvent luckyluke
  ObjectAddedEvent luckyluke
  old manage_afterAdd luckyluke luckyluke btfolder
  ContainerModifiedEvent btfolder
  'luckyluke'

  >>> btfolder.manage_delObjects('luckyluke')
  ObjectWillBeRemovedEvent luckyluke
  old manage_beforeDelete luckyluke luckyluke btfolder
  ObjectRemovedEvent luckyluke
  ContainerModifiedEvent btfolder

Here is what happens for a tree of objects. Let's create a simple one::

  >>> subfolder = MyFolder('subfolder')
  >>> folder._setObject('subfolder', subfolder)
  ObjectWillBeAddedEvent subfolder
  ObjectAddedEvent subfolder
  old manage_afterAdd subfolder subfolder folder
  ContainerModifiedEvent folder
  'subfolder'
  >>> subfolder = folder.subfolder
  >>> ob = MyContent('donald')
  >>> subfolder._setObject('donald', ob)
  ObjectWillBeAddedEvent donald
  ObjectAddedEvent donald
  old manage_afterAdd donald donald subfolder
  ContainerModifiedEvent subfolder
  'donald'

Renaming a tree of objects. Note that manage_beforeDelete is called
bottom-up::

  >>> folder.manage_renameObject('subfolder', 'pluto')
  ObjectWillBeMovedEvent subfolder
  ObjectWillBeMovedEvent donald
  old manage_beforeDelete donald subfolder folder
  old manage_beforeDelete subfolder subfolder folder
  ObjectMovedEvent pluto
  old manage_afterAdd pluto pluto folder
  ObjectMovedEvent donald
  old manage_afterAdd donald pluto folder
  ContainerModifiedEvent folder

Cloning a tree of objects::

  >>> res = folder.manage_clone(folder.pluto, 'mickey')
  ObjectCopiedEvent mickey
  ObjectCopiedEvent donald
  ObjectWillBeAddedEvent mickey
  ObjectWillBeAddedEvent donald
  ObjectAddedEvent mickey
  old manage_afterAdd mickey mickey folder
  ObjectAddedEvent donald
  old manage_afterAdd donald mickey folder
  ContainerModifiedEvent folder
  ObjectClonedEvent mickey
  old manage_afterClone mickey mickey
  ObjectClonedEvent donald
  old manage_afterClone donald mickey
  >>> res.getId()
  'mickey'

New class
=========

If we use classes that don't have any manage_afterAdd & co method,
everything happens correctly::

  >>> from Products.Five.tests.test_event import MyNewFolder, MyNewContent
  >>> app = MyApp('')
  >>> root['app'] = app
  >>> folder = MyNewFolder('folder')
  >>> app._setObject('folder', folder) # doctest: +NORMALIZE_WHITESPACE
  ObjectWillBeAddedEvent folder
  ObjectAddedEvent folder
  ContainerModifiedEvent
  'folder'
  >>> folder = app.folder

  >>> ob = MyNewContent('dogbert')
  >>> folder._setObject('dogbert', ob)
  ObjectWillBeAddedEvent dogbert
  ObjectAddedEvent dogbert
  ContainerModifiedEvent folder
  'dogbert'
  >>> folder.manage_delObjects('dogbert')
  ObjectWillBeRemovedEvent dogbert
  ObjectRemovedEvent dogbert
  ContainerModifiedEvent folder

Now move::

  >>> ob = MyNewContent('dilbert')
  >>> folder._setObject('dilbert', ob)
  ObjectWillBeAddedEvent dilbert
  ObjectAddedEvent dilbert
  ContainerModifiedEvent folder
  'dilbert'
  >>> cp = folder.manage_cutObjects('dilbert')
  >>> folder.manage_pasteObjects(cp)
  ObjectWillBeMovedEvent dilbert
  ObjectMovedEvent dilbert
  ContainerModifiedEvent folder
  [{'new_id': 'dilbert', 'id': 'dilbert'}]

And copy::

  >>> cp = folder.manage_copyObjects('dilbert')
  >>> folder.manage_pasteObjects(cp)
  ObjectCopiedEvent copy_of_dilbert
  ObjectWillBeAddedEvent copy_of_dilbert
  ObjectAddedEvent copy_of_dilbert
  ContainerModifiedEvent folder
  ObjectClonedEvent copy_of_dilbert
  [{'new_id': 'copy_of_dilbert', 'id': 'dilbert'}]

Then rename::

  >>> folder.manage_renameObject('copy_of_dilbert', 'wally')
  ObjectWillBeMovedEvent copy_of_dilbert
  ObjectMovedEvent wally
  ContainerModifiedEvent folder

Or copy using manage_clone::

  >>> res = folder.manage_clone(folder.dilbert, 'phb')
  ObjectCopiedEvent phb
  ObjectWillBeAddedEvent phb
  ObjectAddedEvent phb
  ContainerModifiedEvent folder
  ObjectClonedEvent phb
  >>> res.getId()
  'phb'

Also on a BTreeFolder::

  >>> ob = MyNewContent('alice')
  >>> btfolder._setObject('alice', ob)
  ObjectWillBeAddedEvent alice
  ObjectAddedEvent alice
  ContainerModifiedEvent btfolder
  'alice'
  >>> btfolder.manage_renameObject('alice', 'rabbit')
  ObjectWillBeMovedEvent alice
  ObjectMovedEvent rabbit
  ContainerModifiedEvent btfolder
  >>> btfolder.manage_delObjects('rabbit')
  ObjectWillBeRemovedEvent rabbit
  ObjectRemovedEvent rabbit
  ContainerModifiedEvent btfolder

Now for a tree of objects. Let's create a simple one::

  >>> subfolder = MyNewFolder('subfolder')
  >>> folder._setObject('subfolder', subfolder)
  ObjectWillBeAddedEvent subfolder
  ObjectAddedEvent subfolder
  ContainerModifiedEvent folder
  'subfolder'
  >>> subfolder = folder.subfolder
  >>> ob = MyNewContent('mel')
  >>> subfolder._setObject('mel', ob)
  ObjectWillBeAddedEvent mel
  ObjectAddedEvent mel
  ContainerModifiedEvent subfolder
  'mel'

Renaming a tree of objects::

  >>> folder.manage_renameObject('subfolder', 'firefly')
  ObjectWillBeMovedEvent subfolder
  ObjectWillBeMovedEvent mel
  ObjectMovedEvent firefly
  ObjectMovedEvent mel
  ContainerModifiedEvent folder

Cloning a tree of objects::

  >>> res = folder.manage_clone(folder.firefly, 'serenity')
  ObjectCopiedEvent serenity
  ObjectCopiedEvent mel
  ObjectWillBeAddedEvent serenity
  ObjectWillBeAddedEvent mel
  ObjectAddedEvent serenity
  ObjectAddedEvent mel
  ContainerModifiedEvent folder
  ObjectClonedEvent serenity
  ObjectClonedEvent mel
  >>> res.getId()
  'serenity'

OrderedFolder has the same renaming behavior than before::

  >>> ofolder = MyOrderedFolder('ofolder')
  >>> app._setObject('ofolder', ofolder) # doctest: +NORMALIZE_WHITESPACE
  ObjectWillBeAddedEvent ofolder
  ObjectAddedEvent ofolder
  old manage_afterAdd ofolder ofolder
  ContainerModifiedEvent
  'ofolder'
  >>> ob1 = MyNewContent('ob1')
  >>> ofolder._setObject('ob1', ob1)
  ObjectWillBeAddedEvent ob1
  ObjectAddedEvent ob1
  ContainerModifiedEvent ofolder
  'ob1'
  >>> ob2 = MyNewContent('ob2')
  >>> ofolder._setObject('ob2', ob2)
  ObjectWillBeAddedEvent ob2
  ObjectAddedEvent ob2
  ContainerModifiedEvent ofolder
  'ob2'
  >>> ofolder.manage_renameObject('ob1', 'ob4')
  ObjectWillBeMovedEvent ob1
  ObjectMovedEvent ob4
  ContainerModifiedEvent ofolder
  >>> ofolder.objectIds()
  ['ob4', 'ob2']

When subobjects are reordered, an event about the container is sent::

  >>> ofolder.moveObjectsUp('ob2')
  ContainerModifiedEvent ofolder
  1
  >>> ofolder.objectIds()
  ['ob2', 'ob4']

Now cleanup::

  >>> import transaction
  >>> transaction.abort()
