Python II

Redo the producer/consumer program so that it allows multiple consumers. Each consumer must be able to consume the same data before the producer produces more data. Below it the code to redo.

import time, random from threading import Thread, currentThread, Condition

class SharedCell(object): """Shared data that sequences writing before reading.""" def __init__(self): """Can produce but not consume at startup.""" self.data = -1 self.writeable = True self.condition = Condition()

def setData(self, data): """Second caller must wait until someone has consumed the data before resetting it.""" self.condition.acquire() while not self.writeable: self.condition.wait() print("%s setting data to %d" % \ (currentThread().getName(), data)) self.data = data self.writeable = False self.condition.notify() self.condition.release()

def getData(self): """Caller must wait until someone has produced the data before accessing it.""" self.condition.acquire() while self.writeable: self.condition.wait() print("%s accessing data %d" % \ (currentThread().getName(), self.data)) self.writeable = True self.condition.notify() self.condition.release() return self.data

class Producer(Thread): """A producer of data in a shared cell."""

def __init__(self, cell, accessCount, sleepInterval): Thread.__init__(self, name = "Producer") self.accessCount = accessCount self.cell = cell self.sleepInterval = sleepInterval

def run(self): """Resets the data in the cell and goes to sleep, the given number of times.""" print("%s starting up" % self.getName()) for count in range(self.accessCount): time.sleep(random.randint(1, self.sleepInterval)) self.cell.setData(count + 1) print("%s is done producing " % self.getName())

class Consumer(Thread): """A consumer of data in a shared cell."""

def __init__(self, cell, accessCount, sleepInterval): Thread.__init__(self, name = "Consumer") self.accessCount = accessCount self.cell = cell self.sleepInterval = sleepInterval

def run(self): """Accesses the data in the cell and goes to sleep, the given number of times.""" print("%s starting up " % self.getName()) for count in range(self.accessCount): time.sleep(random.randint(1, self.sleepInterval)) value = self.cell.getData() print("%s is done consuming " % self.getName())

def main(): accessCount = int(input("Enter the number of accesses: ")) cell = SharedCell() p = Producer(cell, accessCount, 4) c = Consumer(cell, accessCount, 4) print("Starting the threads") p.start() c.start()

if __name__ == "__main__": main()