This package define interfaces of container components, and provides container implementations such as a BTreeContainer and OrderedContainer, as well as the base class used by for the Folder implementation.


Containment constraints

Containment constraints allow us to express restrictions on the types of items that can be placed in containers or on the types of containers an item can be placed in. We express these constraints in interfaces. Let's define some container and item interfaces:

>>> from zope.container.interfaces import IContainer
>>> from zope.location.interfaces import IContained
>>> from zope.container.constraints import containers, contains
>>> class IBuddyFolder(IContainer):
...     contains('.IBuddy')

In this example, we used the contains function to declare that objects that provide IBuddyFolder can only contain items that provide IBuddy. Note that we used a string containing a dotted name for the IBuddy interface. This is because IBuddy hasn't been defined yet. When we define IBuddy, we can use IBuddyFolder directly:

>>> class IBuddy(IContained):
...     containers(IBuddyFolder)

Now, with these interfaces in place, we can define Buddy and BuddyFolder classes and verify that we can put buddies in buddy folders:

>>> from zope import interface
>>> @interface.implementer(IBuddy)
... class Buddy:
...     pass
>>> @interface.implementer(IBuddyFolder)
... class BuddyFolder:
...     pass
>>> from zope.container.constraints import checkObject, checkFactory
>>> from zope.component.factory import Factory
>>> checkObject(BuddyFolder(), 'x', Buddy())
>>> checkFactory(BuddyFolder(), 'x', Factory(Buddy))

If we try to use other containers or folders, we'll get errors:

>>> @interface.implementer(IContainer)
... class Container:
...     pass
>>> @interface.implementer(IContained)
... class Contained:
...     pass
>>> checkObject(Container(), 'x', Buddy())
... # doctest: +ELLIPSIS
Traceback (most recent call last):
InvalidContainerType: ...
>>> checkFactory(Container(), 'x', Factory(Buddy))
>>> checkObject(BuddyFolder(), 'x', Contained())
... # doctest: +ELLIPSIS
Traceback (most recent call last):
InvalidItemType: ...
>>> checkFactory(BuddyFolder(), 'x', Factory(Contained))

In the example, we defined the container first and then the items. We could have defined these in the opposite order:

>>> class IContact(IContained):
...     containers('.IContacts')
>>> class IContacts(IContainer):
...     contains(IContact)
>>> @interface.implementer(IContact)
... class Contact:
...     pass
>>> @interface.implementer(IContacts)
... class Contacts:
...     pass
>>> checkObject(Contacts(), 'x', Contact())
>>> checkFactory(Contacts(), 'x', Factory(Contact))
>>> checkObject(Contacts(), 'x', Buddy())
... # doctest: +ELLIPSIS
Traceback (most recent call last):
InvalidItemType: ...
>>> checkFactory(Contacts(), 'x', Factory(Buddy))

The constraints prevent us from moving a container beneath itself (either into itself or another folder beneath it):

>>> container = Container()
>>> checkObject(container, 'x', container)
Traceback (most recent call last):
TypeError: Cannot add an object to itself or its children.
>>> import zope.location.interfaces
>>> import zope.interface
>>> subcontainer = Container()
>>> zope.interface.directlyProvides(subcontainer,
...     zope.location.interfaces.ILocation)
>>> subcontainer.__parent__ = container
>>> checkObject(subcontainer, 'x', container)
Traceback (most recent call last):
TypeError: Cannot add an object to itself or its children.


4.0.0a4 (unreleased)

  • Nothing changed yet.

4.0.0a3 (2013-02-28)

  • Restore Folder pickle forward/backward compatibility with version 3.12.0 after making it inherit from BTreeContainer.

4.0.0a2 (2013-02-21)

  • Allow testing without checkouts of unreleased zope.publisher and ZODB.
  • Added Python 3 Trove classifiers.

4.0.0a1 (2013-02-20)

  • Added support for Python 3.3.
  • Made Folder class inherit from BTreeContainer class, so that the IContainer interface does not need to be re-implemented. Added a data attribute for BBB.
  • Replaced deprecated zope.component.adapts usage with equivalent zope.component.adapter decorator.
  • Replaced deprecated zope.interface.implements usage with equivalent zope.interface.implementer decorator.
  • Dropped support for Python 2.4 and 2.5.
  • Send IContainerModifiedEvent after the container is modified (LP#705600).
  • Preserve the original exception traceback in OrderedContainer.__setitem__.
  • Handle Broken Objects more gracefully
  • Fix a bug that made it impossible to store None values in containers (LP#1070719).

3.12.0 (2010-12-14)

  • Fix detection of moving folders into itself or a subfolder of itself. (#118088)
  • Fixed ZCML-related tests and dependencies.
  • Added zcml extra dependencies.

3.11.1 (2010-04-30)

  • Prefer the standard libraries doctest module to the one from zope.testing.
  • Added compatibility with ZODB3 3.10 by importing the IBroken interface from it directly. Once we can rely on the new ZODB3 version exclusively, we can remove the dependency onto the zope.broken distribution.
  • Never fail if the suggested name is in a wrong type (#227617)
  • checkName first checks the parameter type before the emptiness.

3.11.0 (2009-12-31)

  • Copy two trivial classes from zope.cachedescriptors into this package, which allows us to remove that dependency. We didn't actually use any caching properties as the dependency suggested.

3.10.1 (2009-12-29)

  • Moved zope.copypastemove related tests into that package.
  • Removed no longer used zcml prefix from the configure file.
  • Stop importing DocTestSuite from zope.testing.doctestunit. Fixes compatibility problems with zope.testing 3.8.4.

3.10.0 (2009-12-15)

  • Break testing dependency on
  • Break testing dependency on by moving the code and tests into that package.
  • Import ISite from zope.component after it was moved there from zope.location.

3.9.1 (2009-10-18)

  • Rerelease 3.9.0 as it had a broken Windows 2.6 egg.
  • Marked as part of the ZTK.

3.9.0 (2009-08-28)

  • Previous releases should be versioned 3.9.0 as they are not pure bugfix releases and worth a "feature" release, increasing feature version.

    Packages that depend on any changes introduced in version 3.8.2 or 3.8.3 should depend on version 3.9 or greater.

3.8.3 (2009-08-27)

  • Move IXMLRPCPublisher ZCML registrations for containers from to zope.container for now.

3.8.2 (2009-05-17)

  • Rid ourselves of IContained interface. This interface was moved to zope.location.interfaces. A b/w compat import still exists to keep old code running. Depend on zope.location>=3.5.4.
  • Rid ourselves of the implementations of IObjectMovedEvent, IObjectAddedEvent, IObjectRemovedEvent interfaces and ObjectMovedEvent, ObjectAddedEvent and ObjectRemovedEvent classes. B/w compat imports still exist. All of these were moved to zope.lifecycleevent. Depend on zope.lifecycleevent>=3.5.2.
  • Fix a bug in OrderedContainer where trying to set the value for a key that already exists (duplication error) would actually delete the key from the order, leaving a dangling reference.
  • Partially break dependency on zope.traversing by disusing zope.traversing.api.getPath in favor of using ILocationInfo(object).getPath(). The rest of the runtime dependencies on zope.traversing are currently interface dependencies.
  • Break runtime dependency on by using a zcml condition on the qsubscriber ZCML directive that registers the CheckDependency handler for IObjectRemovedEvent. If is not installed, this subscriber will never be registered. is now a testing dependency only.

3.8.1 (2009-04-03)

  • Fixed misspackaged 3.8.0

3.8.0 (2009-04-03)

  • Change configure.zcml to not depend on Fixes:
  • Moved the declaration of IOrderedContainer.updateOrder to a new, basic IOrdered interface and let IOrderedContainer inherit it. This allows easier reuse of the declaration.

3.7.2 (2009-03-12)

  • Fix: added missing ComponentLookupError, missing since revision 95429 and missing in last release.
  • Adapt to the move of IDefaultViewName from zope.component.interfaces to zope.publisher.interfaces.
  • Add support for reserved names for containers. To specify reserved names for some container, you need to provide an adapter from the container to the zope.container.interfaces.IReservedNames interface. The default NameChooser is now also aware of reserved names.

3.7.1 (2009-02-05)

  • Raise more "Pythonic" errors from __setitem__, losing the dependency on zope.exceptions:

    o zope.exceptions.DuplicationError -> KeyError

    o zope.exceptions.UserError -> ValueError

  • Moved import of IBroken interface to use new zope.broken package, which has no dependencies beyond zope.interface.

  • Made test part pull in the extra test requirements of this package.

  • Split the z3c.recipe.compattest configuration out into a new file, compat.cfg, to reduce the burden of doing standard unit tests.

  • Stripped out bogus develop eggs from buildout.cfg.

3.7.0 (2009-01-31)

  • Split this package off This package is intended to have far less dependencies than
  • This package also contains the container implementation that used to be in