#!/usr/bin/env python

# -*- coding:utf-8 -*-

import Queue

import threading

class ThreadPool(object):

    def __init__(self, max_num=20):

        self.queue = Queue.Queue(max_num)

        for i in xrange(max_num):

            self.queue.put(threading.Thread)

    def get_thread(self):

        return self.queue.get()

    def add_thread(self):

        self.queue.put(threading.Thread)

"""

pool = ThreadPool(10)

def func(arg, p):

    print arg

    import time

    time.sleep(2)

    p.add_thread()

for i in xrange(30):

    thread = pool.get_thread()

    t = thread(target=func, args=(i, pool))

    t.start()

"""

#!/usr/bin/env python

# -*- coding:utf-8 -*-

"""

custom ThreadPool

How to use:

pool = ThreadPool(1)

def callback(status, result):

    # status, execute action status

    # result, execute action return value

    pass

def action(i):

    pass

for i in range(20):

    if pool.stop:

        pool.terminal()

        break

    ret = pool.run(action, (i,), callback)

print 'end'

"""

import Queue

import threading

import contextlib

StopEvent = object()

class ThreadPool(object):

    def __init__(self, max_num):

        self.q = Queue.Queue(max_num)

        self.max_num = max_num

        self.cancel = False

        self.generate_list = []

        self.free_list = []

    def run(self, func, args, callback=None):

        """

        线程池执行一个任务

        :param func: 任务函数

        :param args: 任务函数所需参数

        :param callback: 任务执行失败或成功后执行的回调函数，回调函数有两个参数1、任务函数执行状态；2、任务函数返回值（默认为None，即：不执行回调函数）

        :return: 如果线程池已经终止，则返回True否则None

        """

        if self.cancel:

            return True

        if len(self.free_list) == 0 and len(self.generate_list) < self.max_num:

            self.generate_thread()

        w = (func, args, callback,)

        self.q.put(w)

    def generate_thread(self):

        """

        创建一个线程

        """

        t = threading.Thread(target=self.call)

        t.start()

    def call(self):

        """

        循环去获取任务函数并执行任务函数

        """

        current_thread = threading.currentThread

        self.generate_list.append(current_thread)

        event = self.q.get()

        while event != StopEvent:

            func, arguments, callback = event

            try:

                result = func(*arguments)

                success = True

            except Exception, e:

                success = False

                result = None

            if callback is not None:

                try:

                    callback(success, result)

                except Exception, e:

                    pass

            with self.worker_state(self.free_list, current_thread):

                event = self.q.get()

        else:

            self.generate_list.remove(current_thread)

    def terminal(self):

        """

        终止线程池中的所有线程

        """

        self.cancel = True

        full_size = len(self.generate_list)

        while full_size:

            self.q.put(StopEvent)

            full_size -= 1

    @contextlib.contextmanager

    def worker_state(self, state_list, worker_thread):

        """

        用于记录线程中正在等待的线程数

        """

        state_list.append(worker_thread)

        try:

            yield

        finally:

            state_list.remove(worker_thread)