'''
  threads3.py
  Jeff Ondich, 15 November 2010

  Same as threads2.py, but this time uses a lock to protect the
  critical section.
'''

from threading import *

class FightingThread(Thread):
    def __init__(self, symbol):
        Thread.__init__(self)
        self.symbol = symbol

    def run(self):
        for j in range(100000):
            gLock.acquire()
            for k in range(len(gSharedList)):
                gSharedList[k] = self.symbol
            if gSharedList != [self.symbol] * len(gSharedList):
                print self.symbol, ':', gSharedList
            gLock.release()

gSharedList = ['x', 'x', 'x', 'x', 'x', 'x', 'x', 'x']
gLock = Lock()

threadA = FightingThread('a')
threadB = FightingThread('b')

threadA.start()
threadB.start()