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/proc/thread-self/root/lib/python3.6/site-packages/zope/event/classhandler.py

"""Class-based event handlers


A light-weight event-handler framework based on event classes.

Handlers are registered for event classes:

    >>> import zope.event.classhandler

    >>> class MyEvent(object):
    ...     def __repr__(self):
    ...         return self.__class__.__name__

    >>> def handler1(event):
    ...     print("handler1 %r" % event)

    >>> zope.event.classhandler.handler(MyEvent, handler1)

Descriptor syntax:

    >>> @zope.event.classhandler.handler(MyEvent)
    ... def handler2(event):
    ...     print("handler2 %r" % event)

    >>> class MySubEvent(MyEvent):
    ...     pass

    >>> @zope.event.classhandler.handler(MySubEvent)
    ... def handler3(event):
    ...     print("handler3 %r" % event)


Subscribers are called in class method-resolution order, so only
new-style event classes are supported, and then by order of registry.

    >>> import zope.event
    >>> zope.event.notify(MySubEvent())
    handler3 MySubEvent
    handler1 MySubEvent
    handler2 MySubEvent

"""
import zope.event

registry = {}

def handler(event_class, handler_=None, decorator=False):
    """Define an event handler for a (new-style) class.

    This can be called with a class and a handler, or with just a
    class and the result used as a handler decorator.
    """
    if handler_ is None:
        return lambda func: handler(event_class, func, True)

    if not registry:
        zope.event.subscribers.append(dispatch)

    if event_class not in registry:
        registry[event_class] = [handler_]
    else:
        registry[event_class].append(handler_)

    if decorator:
        return handler

def dispatch(event):
    for event_class in event.__class__.__mro__:
        for handler in registry.get(event_class, ()):
            handler(event)

Name	Size	Perms	Modified	Actions
__pycache__ DIR	-	drwxr-xr-x	2025-04-13 08:21:04	Edit Download recursive recursive
classhandler.py	1.74 KB	lrw-r--r--	2016-02-17 14:26:48	Edit Download recursive recursive
__init__.py	1.07 KB	lrw-r--r--	2014-12-30 14:19:09	Edit Download recursive recursive

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