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。

 1 #Author : Kelvin
 2 #Date : 2019/1/24 20:57
 3 
 4 #控制类的实例化对象时的参数值
 5 
 6 #定义描述符
 7 class Type():
 8     def __init__(self,key,type):
 9         self.key=key
10         self.type=type
11     def __get__(self, instance, owner):
12         # print("get")
13         return instance.__dict__[self.key]
14     def __set__(self, instance, value):
15         # print("set")
16         if not isinstance(value,self.type):
17             raise TypeError("%s Type is not %s"%(self.key,self.type))
18         instance.__dict__[self.key]=value
19     def __delete__(self, instance):
20         # print("delete")
21         instance.__dict__.pop(self.key)
22 
23 
24 #定义装饰器
25 def deco(*args,**kwargs):
26     def wrapper(obj):
27         for k,v in kwargs.items():
28             setattr(obj,k,Type(k,v))
29         return obj
30     return wrapper
31 
32 
33 #定义类
34 @deco(name=str,age=int,salary=float)
35 class People:
36     def __init__(self,name,age,salary):
37         self.name=name
38         self.age=age
39         self.salary=salary
40 p1=People("kelvin",18,12800.36)