# 简单工厂模式

```python
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2019/10/7 4:33 PM
# @Author  : xinfa.jiang
# @Site    : 
# @File    : simple_factory.py
# @Software: PyCharm
'''
简单工厂模式
'''


class Operation(object):
    '''
    property也是class
    @property装饰器负责把一个方法变成属性
    '''

    @property
    def number_a(self):
        return self.__number_a

    @number_a.setter
    def number_a(self, value):
        self.__number_a = value

    @property
    def number_b(self):
        return self.__number_b

    @number_b.setter
    def number_b(self, value):
        self.__number_b = value


class OperationAdd(Operation):
    '''
    继承Operation，实现+操作
    '''

    def get_result(self):
        return self.number_a + self.number_b


class OperationSub(Operation):
    '''
    -操作
    '''

    def get_result(self):
        return self.number_a - self.number_b


class OperationFactory(object):
    '''
    根据输入的operate符号，创建不同的类，这些类都继承Operation
    '''

    @staticmethod
    def create_operation(operate):
        if operate == "+":
            return OperationAdd()
        elif operate == "-":
            return OperationSub()


if __name__ == '__main__':
    # 调用静态方法，直接用，不需要创建()对象。简单工厂直接制造的operation实例
    op = OperationFactory.create_operation('-')
    op.number_a = 10
    op.number_b = 5

    print(op.get_result())
```


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