Python是否具有与Java CountDownLatch类似的控制机制? [英] Does Python have a similar control mechanism to Java's CountDownLatch?

问题描述

因此，我首先要说这是针对家庭作业的.我的教授给了我们一个作业，必须用Java编写一次，并用另一种语言编写一次.我选择第二种语言是Python，因为我至少有点熟悉.该程序必须以以下方式工作:

So, I will start by saying that this is for a homework problem. My professor gave us an assignment which must be written once in Java and once in another language; I chose the second language to be Python since I'm at least a little familiar with it. The program must work in the following way:

启动我们称为父级的主方法/线程.

Start the main method/thread which we will call parent.

从父级开始线程子级1

start thread child 1 from the parent

从线程子代1启动线程孙子代

start thread grandchild from thread child 1

从父级开始线程子级2

start thread child 2 from the parent

从孙子线程中打印孙子

从子2线程中打印子2

print child 2 from the child 2 thread

从子1线程中打印子1

print child 1 from the child 1 thread

从主方法/父线程中打印父级

print parent from the main method/parent thread

这些事情必须按此顺序完成.我已经编写了使用CountDownLatch在Java中执行此操作的代码，以组织这些事情的发生方式.但是，我没有在Python中看到类似的机制(尽管我不像Java那样对Python熟悉).是否有类似的机制也许因为我不知道它叫什么而无法找到?

These things must be done in this order. I have written code that does this in Java using CountDownLatch in order to organize the way these things occur. However, I didn't see a similar mechanism in Python (although I'm less familiar with Python than Java). Is there a similar mechanism that maybe I just can't find because I don't know what it's called?

推荐答案

您可以使用threading.Condition来实现CountDownLatch:

you can implement CountDownLatch using threading.Condition like this:

import threading

class CountDownLatch(object):
    def __init__(self, count=1):
        self.count = count
        self.lock = threading.Condition()

    def count_down(self):
        self.lock.acquire()
        self.count -= 1
        if self.count <= 0:
            self.lock.notifyAll()
        self.lock.release()

    def await(self):
        self.lock.acquire()
        while self.count > 0:
            self.lock.wait()
        self.lock.release()

这篇关于Python是否具有与Java CountDownLatch类似的控制机制?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！