python - 使用线程时访问父类(super class)变量

Question

我有一个带有线程列表的类，这些线程需要访问父类(super class)中的变量。我不确定如何以安全的方式访问该变量以便线程执行其操作。

我想要做什么的想法。

from threading import Thread


class Parent():

    def __init__(self, num):
        self.num = num
        self.arr = []

    def run(self):
        self.arr.append(Child(25))
        self.arr.append(Child(50))
        for child in a.arr:
            child.start()
        for child in a.arr:
            child.join()
        print(self.num)


class Child(Thread, Parent):

    def __init__(self, sum):
        Thread.__init__(self)
        self.sum = sum

    def run(self):
        # every thread should a.num + self.sum so I end up with a.num = 175
        pass


a = Parent(100)
a.run()

Answer 1

在您的特定示例中，您想要:

1. 将父级传递给子级，以便他们知道应该向谁求助
2. 使用Lock同步临界区(加法)

像这样:

from threading import Thread, Lock

class Parent:

    def __init__(self, num):
        self.num = num
        self.arr = []
        self.lock = Lock()  # Create the Lock

    def run(self):
        self.arr.append(Child(25, self))  # pass parent to children
        self.arr.append(Child(50, self))  # 
        for child in a.arr:
            child.start()
        for child in a.arr:
            child.join()
        print(self.num)

class Child(Thread, Parent):

    def __init__(self, sum_, parent):
        Thread.__init__(self)
        self.sum_ = sum_
        self.parent = parent

    def run(self):
        with self.parent.lock:  # this with section will be synchronized
                                # against parent's lock
            self.parent.num += self.sum_

a = Parent(100)
a.run()