使用python写一个线程安全的单例模式

# 使用python写一个线程安全的单例模式
# 参考：https://juejin.cn/post/6844903951624585229
import threading
import time


def synchronized(func):
    func.__lock__ = threading.Lock()

    def lock_func(*args, **kwargs):
        with func.__lock__:
            return func(*args, **kwargs)

    return lock_func


class Singleton(object):
    instance = None

    @synchronized
    def __new__(cls, *args, **kwargs):
        # type kwargs: object
        if cls.instance is None:
            time.sleep(0.5)
            cls.instance = super().__new__(cls)
        return cls.instance


class MyClass(Singleton):
    def __init__(self, a):
        self.a = a


def check(lst):
    for i in range(len(lst)):
        if i > 0 and id(lst[i]) != id(lst[i - 1]):
            return False
    return True


def test(n):
    def func():
        obj = Singleton(9)
        print(id(obj))

    for i in range(n):
        thread = threading.Thread(target=func)
        thread.start()


if __name__ == "__main__":
    test(10)

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