类的装饰器简单应用示例

使用类的装饰器完成：在类实例化对象时，对实例化参数的类型进行限制。

#Author : Kelvin
#Date : 2019/1/24 20:57

#控制类的实例化对象时的参数值

#定义描述符
class Type():
    def __init__(self,key,type):
        self.key=key
        self.type=type
    def __get__(self, instance, owner):
        # print("get")
        return instance.__dict__[self.key]
    def __set__(self, instance, value):
        # print("set")
        if not isinstance(value,self.type):
            raise TypeError("%s Type is not %s"%(self.key,self.type))
        instance.__dict__[self.key]=value
    def __delete__(self, instance):
        # print("delete")
        instance.__dict__.pop(self.key)


#定义装饰器
def deco(*args,**kwargs):
    def wrapper(obj):
        for k,v in kwargs.items():
            setattr(obj,k,Type(k,v))
        return obj
    return wrapper


#定义类
@deco(name=str,age=int,salary=float)
class People:
    def __init__(self,name,age,salary):
        self.name=name
        self.age=age
        self.salary=salary
p1=People("kelvin",18,12800.36)