tuoheng_algN/vodsdk/test/设计模式/单例/demo2.py

24 lines
682 B
Python

# -*- coding: utf-8 -*-
from threading import RLock
class SingletonType(type):
single_lock = RLock()
def __call__(cls, *args, **kwargs): # 创建cls的对象时候调用
with SingletonType.single_lock:
if not hasattr(cls, "_instance"):
cls._instance = super(SingletonType, cls).__call__(*args, **kwargs) # 创建cls的对象
return cls._instance
class Singleton(metaclass=SingletonType):
def __init__(self, name):
self.name = name
single_1 = Singleton('第1次创建')
single_2 = Singleton('第2次创建')
print(single_1.name, single_2.name) # 第1次创建 第1次创建
print(single_1 is single_2)