Multithreaded Priority Queue in Python

The Queue module allows you to create a new queue object that can hold a specific number of items. There are following methods to control the Queue −

  • get() − The get() removes and returns an item from the queue.
  • put() − The put adds item to a queue.
  • qsize() − The qsize() returns the number of items that are currently in the queue.
  • empty() − The empty( ) returns True if queue is empty; otherwise, False.
  • full() − the full() returns True if queue is full; otherwise, False.


import Queue
import threading
import time
exitFlag = 0
class myThread (threading.Thread):
   def __init__(self, threadID, name, q):
      self.threadID = threadID = name
      self.q = q
   def run(self):
      print "Starting " +
      process_data(, self.q)
      print "Exiting " +
def process_data(threadName, q):
   while not exitFlag:
         if not workQueue.empty():
            data = q.get()
            print "%s processing %s" % (threadName, data)
threadList = ["Thread-1", "Thread-2", "Thread-3"]
nameList = ["One", "Two", "Three", "Four", "Five"]
queueLock = threading.Lock()
workQueue = Queue.Queue(10)
threads = []
threadID = 1
# Create new threads
for tName in threadList:
thread = myThread(threadID, tName, workQueue)
threadID += 1
# Fill the queue
for word in nameList:
# Wait for queue to empty
while not workQueue.empty():
# Notify threads it's time to exit
exitFlag = 1
# Wait for all threads to complete
for t in threads:
print "Exiting Main Thread"

When the above code is executed, it produces the following result −

Starting Thread-1
Starting Thread-2
Starting Thread-3
Thread-1 processing One
Thread-2 processing Two
Thread-3 processing Three
Thread-1 processing Four
Thread-2 processing Five
Exiting Thread-3
Exiting Thread-1
Exiting Thread-2
Exiting Main Thread