# -*- coding: utf-8 -*-
from watson.common.imports import get_qualified_name
[docs]class Event(object):
"""A base event that can be subclassed for use with an EventDispatcher.
Example:
.. code-block:: python
def my_listener(event):
print(event.params['config'])
dispatcher.add('MyEvent', my_listener)
event = Event('MyEvent')
event.params['config'] = {'some': 'config'}
dispatcher.trigger(event)
"""
_name = None
_params = None
_stop_propagation = False
target = None
@property
[docs] def name(self):
"""The name of the event
"""
return self._name
@property
def params(self):
"""A dictionary of parameters that can be included within an Event.
"""
if not self._params:
self._params = {}
return self._params
@params.setter
[docs] def params(self, params):
"""Set the parameters for the event.
Args:
params (dict): data that is to be sent with the event
"""
if isinstance(params, dict):
self._params = params
else:
raise TypeError('Event params must be a dictionary.')
[docs] def __init__(self, name, target=None, params=None):
"""Initializes the event.
Initialize the Event based on an event name. The name will be used
when the event is triggered from the event dispatcher.
Args:
name (string): the name of the event
target (mixed): the originating target of the event
params (dict): the params associated with the event
"""
self._name = str(name)
self.target = target
if params is not None:
self.params = params
@property
[docs] def stopped(self):
"""Return whether or not the event has been stopped.
"""
return bool(self._stop_propagation)
[docs] def stop_propagation(self):
"""Prevents the event from triggering any more event listeners.
This should be used within an event listener when you wish to halt
any further listeners from being triggered.
"""
self._stop_propagation = True
def __repr__(self):
return '<{0} name:{1}>'.format(get_qualified_name(self), self.name)