python多线程：小牛吃草案例

# By Chang

"""
Cow
    weight 0-5//体重标志牛 吃草次数
    tag= //标志牛是否长大
    eat() 吃草
Rain
    ifRain() //判断是否下雨
Grass
    height 0-3 //高度标志草是否成熟
    isRipe //艹是否成熟
    grow（）// 草成长。

"""
import random
import threading
import time


class Cow:
    def __init__(self):
        self.weight = 0
        self.tag = False

    def eat(self):
        if self.weight < 5:
            self.weight += 1
        if self.weight == 5:
            self.tag = True


class Rain:
    @staticmethod
    def if_rain():
        temp = random.choice([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
        return temp < 2
        # 下雨的概率只有20%


class Grass:
    def __init__(self):
        self.height = 0
        self.isRipe = False

    def grow(self):

        if self.height < 3:
            self.height += 1
        if self.height == 3:
            self.isRipe = True


class CowThread(threading.Thread):
    def __init__(self, threadId, cow):
        threading.Thread.__init__(self)
        self.threadId = threadId
        self.cow = cow

    def run(self):
        print(str(self.threadId) + "号线程开始")
        while not self.cow.tag:
            lock.acquire()
            if grass.isRipe:
                self.cow.eat()
                grass.height = 0
                grass.isRipe = False
                temp = str(self.threadId) + "号牛把草吃完了"
                write_line(temp)
            lock.release()
        print(str(self.threadId) + "号牛长大了")
        write_line(str(self.threadId) + "号牛长大了")


lock = threading.Lock()
flock = threading.Lock()
grass = Grass()
cows = []
threads = []


for i in range(10):
    cows.append(Cow())

i = 1
for cow in cows:
    threads.append(CowThread(i, cow))
    i += 1

# 如果文件已存在则清空，不存在则新建
f = open("log.txt", "w", encoding="utf-8")
f.close()

for t in threads:
    # t.setDaemon(True)
    t.start()


def write_line(line):
    f = open("log.txt", "a", encoding="utf-8")
    flock.acquire()
    f.write(time.ctime(time.time()) + ' ' + line + '\n')
    flock.release()
    f.close()


def day_start(grass):
    if Rain.if_rain():
        lock.acquire()
        if not grass.isRipe:
            grass.grow()
            temp = "下雨了," + "草长到了" + str(grass.height) + "英寸"
            write_line(temp)
        else:
            temp = "下雨了," + "草已经长大了"
            write_line(temp)
        lock.release()
    else:
        temp = "天没下雨"
        write_line(temp)


while 1:
    day_start(grass)
    label = True
    # TODO 调整判断策略
    for cow in cows:
        if not cow.tag:
            label = cow.tag
            break
    if label:
        break

for t in threads:
    t.join()
print("mainThread exit")