(九)9-1queue模块

Queue是python标准库中的线程安全的队列（FIFO）实现,提供了一个适用于多线程编程的先进先出的数据结构，即队列，用来在生产者和消费者线程之间的信息传递

Queue对象实现一个fifo队列。queue只有maxsize一个构造参数，用来指定队列容量，指定为0的时候代表容量无限。主要有以下成员函数：
Queue.qsize()：返回消息队列的当前空间。返回的值不一定可靠。
Queue.empty()：判断消息队列是否为空，返回True或False。同样不可靠。
Queue.full()：类似上边，判断消息队列是否满
Queue.put(item, block=True, timeout=None)：往消息队列中存放消息。block可以控制是否阻塞，timeout指定阻塞时候的等待时间。如果不阻塞或者超时，会引起一个full exception。
Queue.put_nowait(item)：相当于put(item, False).
Queue.get(block=True, timeout=None)：获取一个消息，其他同put。

以下两个函数用来判断消息对应的任务是否完成。
Queue.task_done()：接受消息的线程通过调用这个函数来说明消息对应的任务已完成。
Queue.join()： 实际上意味着等到队列为空，再执行别的操作

例子：

from  Queue import Queue
from threading import  Thread
import  time

class Proceduer(Thread):
    def __init__(self,queue):
        super(Proceduer, self).__init__()
        self.queue = queue
    def run(self):
        try :
            for i in xrange(1,10):
                print("put data is {0} to queue".format(i))
                self.queue.put(i)
        except Exception as e:
            print ("put data error")
            raise  e

class Consumer_odd(Thread):
    def __init__(self,queue):
        super(Consumer_odd, self).__init__()
        self.queue = queue
    def run(self):
        try:
            while not self.queue.empty():
                number = self.queue.get(block=True,timeout=5)
                if number % 2 != 0 :
                    print("get {0} from queue ODD".format(number))
                else:
                    self.queue.put(number)
                time.sleep(1)
        except Exception as e :
            raise e

class Consumer_even(Thread):
    def __init__(self,queue):
        super(Consumer_even, self).__init__()
        self.queue = queue
    def run(self):
        try:
            while not self.queue.empty():
                number = self.queue.get(block=True,timeout=5)
                if number % 2 == 0 :
                    print("get {0} from queue EVEN ,thread name is: {1}".format(number,self.getName()))
                else:
                    self.queue.put(number)
                time.sleep(1)
        except Exception as e :
            raise e

def main():
    queue = Queue()
    print queue
    p = Proceduer(queue=queue)
    print p
    p.start()
    p.join()
    time.sleep(1)
    c1 = Consumer_odd(queue=queue)
    c2 = Consumer_even(queue=queue)
    c1.start()
    c2.start()
    c1.join()
    c2.join()
    print("all terminate!")

if __name__ == '__main__':
    main()

运行结果：

<Queue.Queue instance at 0x0000000002B02EC8>
<Proceduer(Thread-1, initial)>
put data is 1 to queue
put data is 2 to queue
put data is 3 to queue
put data is 4 to queue
put data is 5 to queue
put data is 6 to queue
put data is 7 to queue
put data is 8 to queue
put data is 9 to queue
get 1 from queue ODD
get 2 from queue EVEN ,thread name is: Thread-3
get 5 from queue ODD
get 6 from queue EVEN ,thread name is: Thread-3
get 9 from queue ODD
get 4 from queue EVEN ,thread name is: Thread-3
 get 7 from queue ODD
get 8 from queue EVEN ,thread name is: Thread-3
get 3 from queue ODD
all terminate!