Source code for ayx_plugin_sdk.providers.amp_provider.repositories.singleton

# Copyright (C) 2020 Alteryx, Inc. All rights reserved.
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#    http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
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"""Singleton metaclass."""


[docs]class Singleton(type): """Implements the Singleton Design Pattern using metaclasses. References ---------- [1] Mastering Python Design Patterns, Singleton. """ _instances = {} # type: ignore def __call__(cls, *args, **kwargs): # type: ignore """Call.""" if cls not in cls._instances: cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs) return cls._instances[cls]