# L-27 MCS 275 Mon 17 Mar 2008 : class consumer

# Illustration of producer/consumer with threads.
# An object of the class Consumer is a thread that
# will pop integers from the queue and print them,
# at a given pace.

import threading
import random
import time

class Consumer(threading.Thread):
   """
   Pops integers from a queue.
   """
   def __init__(self,t,q,n,p):
      "thread t to pop n integers from q"
      threading.Thread.__init__(self,name=t)
      self.queue = q
      self.amount = n
      self.pace = p

   def run(self):
      "pops integers at some pace"
      print "consumption starts..."
      for i in range(0,self.amount):
         r = random.randint(1,self.pace)
         print self.getName() + \
             " sleeps %d seconds" % r
         time.sleep(r)
         while True:
            try:
               i = self.queue.pop(0)
               print "popped %d from queue" % i
               break
            except IndexError:
               print "wait a second..."
               time.sleep(1)
      print "consumption terminated"