Blocking_Queue.py

"""
#####From Tango Interview Challenge
This is pretty important design pattern, including the knowledge of thread

######Using Queue
"""

from threading import Thread
import time
import random
from Queue import Queue

queue = Queue(10)

class ProducerThread(Thread):
    def run(self):
        nums = range(5)
        global queue
        while True:
            num = random.choice(nums)
            queue.put(num, True)
            print "Produced", num
            time.sleep(random.random())


class ConsumerThread(Thread):
    def run(self):
        global queue
        while True:
            num = queue.get(True)
            queue.task_done()
            print "Consumed", num
            time.sleep(random.random())


ProducerThread().start()
ConsumerThread().start()

```

######Using Condition

```python
from threading import Thread, Condition
import time
import random

queue = []
MAX_NUM = 10
condition = Condition()

class ProducerThread(Thread):
    def run(self):
        nums = range(5)
        global queue
        while True:
            condition.acquire()
            if len(queue) == MAX_NUM:
                print "Queue full, producer is waiting"
                condition.wait()
                print "Space in queue, Consumer notified the producer"
            num = random.choice(nums)
            queue.append(num)
            print "Produced", num
            condition.notify()
            condition.release()
            time.sleep(random.random())


class ConsumerThread(Thread):
    def run(self):
        global queue
        while True:
            condition.acquire()
            if not queue:
                print "Nothing in queue, consumer is waiting"
                condition.wait()
                print "Producer added something to queue and notified the consumer"
            num = queue.pop(0)
            print "Consumed", num
            condition.notify()
            condition.release()
            time.sleep(random.random())

ProducerThread().start()
ConsumerThread().start()
```

######Helper functions

```python
import random

def checker(func):
    def wrapped():
        value = func()
        if value == 0:
            print 'correct'
        elif value == 1:
            print 'fail'
        else:
            print 'exception'
    return wrapped


@checkergmail
def random_result():
    result = random.choice([0,1,2])
    print result
    return result

random_result()