single_lock=RLock()def__call__(cls, *args, **kwargs):#创建cls的对象时候调用with SingletonType.single_lock:ifnothasattr(cls,"_instance"): cls._instance= super(SingletonType, cls).__call__(*args, **kwargs)#创建cls的对象returncls._instanceclassSingleton(metaclass=SingletonType):def__init_...
Lead to call this function recursivelyreturncls._instanceclassmy_cls(object): __metaclass__ = Singleton 这个例子中我们使用元类Singleton替代默认使用type方式创建类my_cls。可以将类my_cls看做是元类Singleton的一个对象,当我们使用my_cls(...)的方式创建类my_cls的对象时,实际上是在调用元类Singleton的对...
# 定义一个元类Metaclass class Metaclass(type): # *args返回的元组内容为(类名,父类,dict(属性和方法)) def __new__(cls, *args, **kwargs): # 创建时调用 if 'c' in args[2]: # 判断属性中有无属性名为c的 args[2]['c']='Exchange' # 将属性c的值改为Exchange return type.__new__(...
class Singleton: _instance = None def __new__(cls): if cls._instance is None: cls._instance = super(Singleton, cls).__new__(cls) return cls._instance # 使用单例模式 s1 = Singleton() s2 = Singleton() print(s1 == s2) # 输出: True print(s1 is s2) # 输出: True 这个...
class Singleton(type): _instances = {} def __call__(cls, *args, **kwargs): if cls not in cls._instances: cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs) return cls._instances[cls] class Cls4(metaclass=Singleton): pass cls1 = Cls4() cls2 = Cls4()...
s2 = MySingleton("instance two") print(s1.value) # 输出: instance one print(s2.value) # 输出: instance one ,证明s1和s2是同一个实例7.2 类装饰器实现单例 类装饰器提供了一种面向对象的方式来实现单例模式,可以封装更多的逻辑。 class SingletonMeta(type): ...
1 class Singleton(type): 2 def __init__(cls, name, bases, dic): 3 super(Singleton, cls).__init__(name, bases, dic) 4 cls._instance = None 5 6 def __call__(cls, *args, **kwargs): 7 if cls._instance is None: 8 cls._instance = super(Singleton, cls).__call__(*args...
classSingleton(object): def__init__(self, cls): self._cls = cls self._instance = {} def__call__(self): ifself._clsnotinself._instance: self._instance[self._cls] = self._cls returnself._instance[self._cls] @Singleton classCls2(object): ...
classSingleton(type):def__init__(cls,*args,**kwargs):cls.__instance=Nonesuper().__init__(*args,**kwargs)def__call__(cls,*args,**kwargs):ifcls.__instance is None:cls.__instance=super().__call__(*args,**kwargs)returncls.__instanceelse:returncls.__instanceclassLogger(metaclass...
class Singleton(): def __init__(self, name): = name def do_something(self): pass singleton = Singleton('模块单例') 1. 2. 3. 4. 5. 6. 7. 8. 在其他脚本里 AI检测代码解析 from my_singleton import singleton 1. 在任何引用singleton的脚本里,singleton都是同一个对象,这就确保了系统中只...