Created
January 16, 2011 09:16
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Producer Consumer using Semaphores
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""" | |
Producer produces numbers 1..10 | |
Consumer runs first & then blocks | |
Solution: uses semaphores | |
""" | |
from threading import Thread | |
from threading import Semaphore | |
class SharedBuffer(object): | |
def __init__(self): | |
self.empty = Semaphore(0) | |
self.mutex = Semaphore(1) | |
self.slot = [] | |
def put(self, p): | |
""" blocking put """ | |
self.mutex.acquire() | |
try: | |
print "put " + str(p) | |
self.slot.append( p ) | |
except: | |
print "failed to append" | |
self.mutex.release() | |
self.empty.release() | |
def get(self): | |
""" blocking get """ | |
self.empty.acquire() | |
self.mutex.acquire() | |
v = self.slot.pop() | |
self.mutex.release() | |
print "get " + str(v) | |
return v | |
class Producer(Thread): | |
def __init__(self,buffer): | |
Thread.__init__(self) | |
self.buffer = buffer | |
def run(self): | |
print "[Producer] running" | |
for i in range(0, 10): | |
self.buffer.put( i ) | |
print "[Producer] sent " + str(i) | |
print "[Producer] dead" | |
class Consumer(Thread): | |
def __init__(self,buffer): | |
Thread.__init__(self) | |
self.buffer = buffer | |
def run(self): | |
print "[Consumer] running" | |
while(True): | |
v = self.buffer.get() | |
print "[Consumer] received " + str(v) | |
if( v == 9 ): | |
break | |
print "[Consumer] dead" | |
if __name__ == "__main__": | |
buffer = SharedBuffer() | |
p = Producer(buffer) | |
c = Consumer(buffer) | |
c.start() | |
p.start() | |
c.join() |
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