python - 正确的类继承

Question

我编写了一些代码，允许普遍使用术语“工作”来执行独特的任务。可以通过设置初始变量“job_type”来选择具体的作业。从该初始变量中选择一个特定的子类来执行适当的工作。也许代码会更有意义:)

if __name__=='__main__':
    # these variables would normally be called in from a config file
    job_type = 'job1'
    uni_var = 10

    job_select = superClass(job_type, uni_var)
    job_select.job()        


class superClass(object):
    def __init__(self, job_type, uni_var):
        self.job_type = job_type   
        self.uni_var = uni_var

        if self.job_type == 'job1':
            self.jobChoice = option1()
        else:
            self.jobChoice = option2()

    # This is the definition called by the main function it then
    # redirects the request to the appropriate job sub class   
    def job(self):
        self.jobChoice.job()

class option1(superClass):
    def __init__(self):
        pass

    def job(self):
        print 'job option 1'
        print uni_var

class option2(superClass):
    def __init__(self):
        pass

    def job(self):
        print 'job option 2'
        print uni_var

此代码背后的想法是允许单个/常量“main”函数纯粹基于变量“job_type”来执行各种独特的任务。看起来效果不错。

我的问题(作为一个非常缺乏经验的编码员)是，我是否以正确的方式处理这个问题，或者是否有更好的方法来做事？

此外，我是否在父类(super class)中正确设置了变量“uni_var”，以便在所有/任何父类(super class)子类之间正确共享？

谢谢。

Answer 1

我怀疑您真正想要的是使用 Factory Method Pattern在这里。

您可以将代码更改为如下所示:

if __name__=='__main__':
    # these variables would normally be called in from a config file
    job_type = 'job1'
    uni_var = 10

    job_select = superClass.optionFactory(job_type, uni_var)
    job_select.job()        


class superClass(object):
    def __init__(self, job_type, uni_var):
        self.job_type = job_type   
        self.uni_var = uni_var

    # This is the definition called by the main function it then
    # redirects the request to the appropriate job sub class   
    def job(self):
        raise NotImplementedError()

    @staticmethod
    def optionFactory(job_type, uni_var):
        "Return an instance of superClass based on job_type and uni_var."
        if job_type == "job1":
            return option1(job_type, uni_var)
        else:
            return option2(job_type, uni_var)

class option1(superClass):
    def __init__(self, job_type, uni_var):
        super(option1, self).__init__(job_type, uni_var)

    def job(self):
        print 'job option 1'
        print uni_var

class option2(superClass):
    def __init__(self, job_type, uni_var):
        super(option2, self).__init__(job_type, uni_var)

    def job(self):
        print 'job option 2'
        print uni_var

但是，请注意，此实现将要求每次创建新子类时都更改 superClass。另一种选择是使 optionFactory 方法成为独立函数(而不是 superClass 的方法)。像这样:

if __name__=='__main__':
    # these variables would normally be called in from a config file
    job_type = 'job1'
    uni_var = 10

    job_select = optionFactory(job_type, uni_var)
    job_select.job()        


class superClass(object):
    def __init__(self, job_type, uni_var):
        self.job_type = job_type   
        self.uni_var = uni_var

    # This is the definition called by the main function it then
    # redirects the request to the appropriate job sub class   
    def job(self):
        raise NotImplementedError()

class option1(superClass):
    def __init__(self, job_type, uni_var):
        super(option1, self).__init__(job_type, uni_var)

    def job(self):
        print 'job option 1'
        print uni_var

class option2(superClass):
    def __init__(self, job_type, uni_var):
        super(option2, self).__init__(job_type, uni_var)

    def job(self):
        print 'job option 2'
        print uni_var

def optionFactory(job_type, uni_var):
    "Return an instance of superClass based on job_type and uni_var."
    if job_type == "job1":
        return option1(job_type, uni_var)
    else:
        return option2(job_type, uni_var)