ncclient:NETCONF Python client

# Copyright 2009 Shikhar Bhushan

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

#    http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

from threading import Lock

import logging

logger = logging.getLogger('ncclient.subject')

class Subject:

    def __init__(self, listeners=[]):

        self._listeners = set(listeners)

        self._lock = Lock()

    def has_listener(self, listener):

        with self._lock:

            return (listener in self._listeners)

    def add_listener(self, listener):

        with self._lock:

            self._listeners.add(listener)

    def remove_listener(self, listener):

        with self._lock:

            self._listeners.discard(listener)

    def dispatch(self, event, *args, **kwds):

        # holding the lock while doing callbacks could lead to a deadlock

        # if one of the above methods is called

        with self._lock:

            listeners = list(self._listeners)

        for l in listeners:

            try:

                logger.debug('dispatching [%s] to [%s]' % (event, l))

                getattr(l, event)(*args, **kwds)

            except Exception as e:

                logger.warning(e)