打印机任务模拟

# 打印机设置
class Printer:
    def __init__(self, ppm):
        self.pagerate = ppm
        self.currentTask = None
        self.timeRemaining = 0

    def tick(self):
        if self.currentTask is not None:
            self.timeRemaining = self.timeRemaining - 1
            if self.timeRemaining <= 0:
                self.currentTask = None

    def busy(self):
        if self.currentTask is not None:
            return True
        return False

    def startNext(self, newtask):
        self.currentTask = newtask
        self.timeRemaining = newtask.getPages() * 60 / self.pagerate


# 任务设置
class Task:
    def __init__(self, time):
        self.timestamp = time
        self.pages = random.randrange(1, 21)

    def getStamp(self):
        return self.timestamp

    def getPages(self):
        return self.pages

    def waitTime(self, currenttime):
        return currenttime - self.timestamp


# 生成任务
import random
import time


def newPrintTask():
    num = random.randrange(1, 181)
    if num == 180:
        return True
    return False


# 模拟打印过程
def simulation(numSeconds, pagesPerMinute):
    labprinter = Printer(pagesPerMinute)
    printList = []
    waitingtimes = []
    for currentSecond in range(numSeconds):
        if newPrintTask():
            printList.append(Task(currentSecond))
        if (not labprinter.busy()) and printList:
            nexttask = printList.pop(0)
            waitingtimes.append(nexttask.waitTime(currentSecond))
            labprinter.startNext(nexttask)
        labprinter.tick()
    if len(waitingtimes) == 0:
        averagewait = 0
    else:
        averagewait = sum(waitingtimes) / len(waitingtimes)
    print('average wait %6.2f secs %4d tasks remain.' % (averagewait, len(printList)))


if __name__ == '__main__':
    for i in range(10):
        simulation(3600, 10)

 

输出：

average wait 4.06 secs 0 tasks remain.
average wait 10.96 secs 0 tasks remain.
average wait 18.25 secs 0 tasks remain.
average wait 9.35 secs 0 tasks remain.
average wait 11.95 secs 0 tasks remain.
average wait 29.31 secs 0 tasks remain.
average wait 14.95 secs 1 tasks remain.
average wait 7.12 secs 0 tasks remain.
average wait 9.86 secs 0 tasks remain.
average wait 2.46 secs 0 tasks remain.