root/cpsskins/branches/jmo-perspectives/controllers/controller.py

##############################################################################
#
# Copyright (c) 2005-2006 Nuxeo and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""

$Id$
"""
__docformat__ = "reStructuredText"

from zope.app.copypastemove import dispatchToSublocations
from zope.interface import implements

from cpsskins.controllers.interfaces import IController
from cpsskins.utils import getThemeManager

class Controller(object):
    """Base controller with a set of handlers for the most common events.

    Element controllers are element adapters that provide IController.

    When a monitored event occurs on an element, the event is dispatched
    to the registered controller.

    Controllers should subclass this base class since the list of events may
    be extended in the future.
    """
    implements(IController)

    def __init__(self, element):
        self.element = element

    def created(self):
        """What to do when an element has been created."""

    def added(self):
        """What to do when an element has been added to a container."""

    def removed(self):
        """What to do when an element has been removed from a container."""

    def modified(self):
        """What to do when an element has been modified."""

# Event handlers: events get dispatched to the controllers.

def elementCreated(element, event):
    """This suscriber is called when an element has been created.
    """
    controller = IController(element, None)
    if controller is not None:
        controller.created()

def elementAdded(element, event):
    """This suscriber is called when an element has been added to a container.
    """
    # register the element
    getThemeManager().registerElement(element)

    # get the object's controller
    controller = IController(element, None)
    if controller is not None:
        controller.added()

    # propagate the event to sublocations
    dispatchToSublocations(element, event)

def elementRemoved(element, event):
    """This suscriber is called when an element has been removed from a
    container.
    """
    tmutil = getThemeManager()
    # the element may be removed from a folder above the theme manager
    if tmutil is None:
        return

    # get the object's controller
    controller = IController(element, None)
    if controller is not None:
        controller.removed()

    # unregister the element
    tmutil.unregisterElement(element)

def elementModified(element, event):
    """This suscriber is called when an element has been modified.
    """
    # get the object's controller
    controller = IController(element, None)
    if controller is not None:
        controller.modified()