63 lines
1.9 KiB
Python
63 lines
1.9 KiB
Python
# Copyright 2015 Cloudbase Solutions.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# 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, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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class BasePollingManager(object):
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def __init__(self):
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self._force_polling = False
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self._polling_completed = True
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def force_polling(self):
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self._force_polling = True
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def polling_completed(self):
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self._polling_completed = True
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def _is_polling_required(self):
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raise NotImplementedError()
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@property
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def is_polling_required(self):
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# Always consume the updates to minimize polling.
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polling_required = self._is_polling_required()
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# Polling is required regardless of whether updates have been
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# detected.
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if self._force_polling:
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self._force_polling = False
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polling_required = True
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# Polling is required if not yet done for previously detected
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# updates.
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if not self._polling_completed:
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polling_required = True
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if polling_required:
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# Track whether polling has been completed to ensure that
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# polling can be required until the caller indicates via a
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# call to polling_completed() that polling has been
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# successfully performed.
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self._polling_completed = False
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return polling_required
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class AlwaysPoll(BasePollingManager):
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@property
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def is_polling_required(self):
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return True
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