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#
# Copyright (c) 2006 The Apache Software Foundation
#
# 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.
#
"""
This module augments the standard python multithreaded Queue
implementation to add a close() method so that threads blocking on the
content of a queue can be notified if the queue is no longer in use.
"""
from Queue import Queue as BaseQueue, Empty, Full
class Closed(Exception): pass
class Queue(BaseQueue):
END = object()
def close(self):
self.put(Queue.END)
def get(self, block = True, timeout = None):
result = BaseQueue.get(self, block, timeout)
if result == Queue.END:
# this guarantees that any other waiting threads or any future
# calls to get will also result in a Closed exception
self.put(Queue.END)
raise Closed()
else:
return result
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