5baff7dc3e
In some part in the code we import objects. In the Openstack style guidelines they recommand to import only modules. We need to fix that. Change-Id: I4bfee2b94d101940d615f78f9bebb83310ed90ba Partial-Bug:1543101
79 lines
2.7 KiB
Python
79 lines
2.7 KiB
Python
# -*- encoding: utf-8 -*-
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# Copyright (c) 2015 b<>com
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from oslo_log import log
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from watcher.decision_engine.messaging import events as messaging_events
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LOG = log.getLogger(__name__)
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class EventDispatcher(object):
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"""Generic event dispatcher which listen and dispatch events"""
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def __init__(self):
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self._events = dict()
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def __del__(self):
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self._events = None
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def has_listener(self, event_type, listener):
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"""Return true if listener is register to event_type """
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# Check for event type and for the listener
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if event_type in self._events.keys():
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return listener in self._events[event_type]
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else:
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return False
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def dispatch_event(self, event):
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LOG.debug("dispatch evt : %s" % str(event.type))
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"""
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Dispatch an instance of Event class
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"""
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if messaging_events.Events.ALL in self._events.keys():
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listeners = self._events[messaging_events.Events.ALL]
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for listener in listeners:
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listener(event)
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# Dispatch the event to all the associated listeners
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if event.type in self._events.keys():
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listeners = self._events[event.type]
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for listener in listeners:
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listener(event)
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def add_event_listener(self, event_type, listener):
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"""Add an event listener for an event type"""
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# Add listener to the event type
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if not self.has_listener(event_type, listener):
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listeners = self._events.get(event_type, [])
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listeners.append(listener)
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self._events[event_type] = listeners
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def remove_event_listener(self, event_type, listener):
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"""Remove event listener. """
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# Remove the listener from the event type
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if self.has_listener(event_type, listener):
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listeners = self._events[event_type]
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if len(listeners) == 1:
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# Only this listener remains so remove the key
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del self._events[event_type]
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else:
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# Update listeners chain
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listeners.remove(listener)
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self._events[event_type] = listeners
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