===============
Time annotators
===============

Time annotators store the creation resp. last modification time of an object.

Set up
======

>>> class Content(object):
...     created = None
...     modified = None

The annotations are stored on the ``IZopeDublinCore`` adapter. This dummy adapter
reads and writes from/to the context object. 

>>> import zope.component
>>> import zope.dublincore.interfaces
>>> class DummyDublinCore(object):
...     def __init__(self, context):
...         self.__dict__['context'] = context
...
...     def __getattr__(self, name):
...         return getattr(self.context, name)
...
...     def __setattr__(self, name, value):
...         setattr(self.context, name, value)

>>> zope.component.provideAdapter(
...     DummyDublinCore, (Content,), zope.dublincore.interfaces.IZopeDublinCore)

Created annotator
=================

The created annotator sets creation and modification time to current time.

>>> content = Content()

It is registered for the ``ObjectCreatedEvent``:

>>> import zope.dublincore.timeannotators
>>> import zope.lifecycleevent.interfaces
>>> zope.component.provideHandler(
...     zope.dublincore.timeannotators.CreatedAnnotator,
...     (zope.lifecycleevent.interfaces.IObjectCreatedEvent,))

>>> import zope.event
>>> import zope.lifecycleevent
>>> zope.event.notify(zope.lifecycleevent.ObjectCreatedEvent(content))

Both ``created`` and ``modified`` get set:

>>> content.created
datetime.datetime(<DATETIME>, tzinfo=<UTC>)
>>> content.modified
datetime.datetime(<DATETIME>, tzinfo=<UTC>)

Modified annotator
==================

The modified annotator only sets the modification time to current time.

>>> content = Content()

It is registered for the ``ObjectModifiedEvent``:

>>> zope.component.provideHandler(
...     zope.dublincore.timeannotators.ModifiedAnnotator,
...     (zope.lifecycleevent.interfaces.IObjectModifiedEvent,))
>>> zope.event.notify(zope.lifecycleevent.ObjectModifiedEvent(content))

Only ``modified`` gets set:

>>> print content.created
None
>>> content.modified
datetime.datetime(<DATETIME>, tzinfo=<UTC>)