Python 设计模式--简单工厂模式

 1 #!/usr/bin/env python
 2 #-*- coding: utf-8 -*-
 3 
 4 class Operation:
 5     def getResult(self):
 6         pass
 7 
 8 class OperationAdd(Operation):
 9     def getResult(self):
10         return self.op1+self.op2
11 
12 class OperationSub(Operation):
13     def getResult(self):
14         return self.op1-self.op2
15     
16 class OperationMul(Operation):
17     def getResult(slef):
18         return self.op1*self.op2
19 
20 class OperationDiv(Operation):
21     def getResult(self):
22         try:
23             return self.op1/float(self.op2)
24         except:
25             print("Error:除数为0！")
26             return 0
27 
28 class OperationOther(Operation):
29     def getResult(self):
30         print("Error:没有定义的运算符！")
31         return 0
32     
33 
34 class OperationFactory:
35     
36     operation = {}
37     operation["+"] = OperationAdd()
38     operation["-"] = OperationSub()
39     operation["*"] = OperationMul()
40     operation["/"] = OperationDiv()
41     
42     def createOperation(self,choice):
43         if choice in self.operation.keys():
44             op = self.operation[choice]
45         else:
46             op = OperationOther()
47         return op
48 
49 
50 
51 if __name__ == "__main__":
52     op = raw_input("请输入运算符：")
53     num_a = input("a:")
54     num_b = input("b:")
55 
56     factory = OperationFactory()
57     cal = factory.createOperation(op)
58 
59     cal.op1 = num_a
60     cal.op2 = num_b
61     
62     print(u"运算结果为：" + str(cal.getResult()))
63 

class Entity():     #实体
    def Func(self):
        "方法体"
　　　　 #pass

class Variant1(Entity):
    def Func(self):
　　　　 pass


class Variant2(Entity):
    def Func(self):
　　　　 pass

class EntityFactory():
    def create_variant(self,choice):
        #根据choice创建不同的variant类
        #函数体
        #return
        

factory  = EntityFactory()
variant = factory.create_variant(choice)
print(variant.Func())