析构函数 实例析构 类析构

#!python
# -*- coding:utf-8 -*-
# 场景：
# 目的：通过单例实现客户端调用sdk时,sdk中的方法对客户端数据的批处理

# 参考：
# {
# Python单例模式(Singleton)的N种实现 - 知乎
# https://zhuanlan.zhihu.com/p/37534850

# 设计模式(Python)-单例模式 - 简书
# https://www.jianshu.com/p/ec6589e02e2f

# http://xiaorui.cc/2016/04/10/python多线程下保持单例模式的实例唯一/

# PythonDecoratorLibrary - Python Wiki
# https://wiki.python.org/moin/PythonDecoratorLibrary

# 3. Data model — Python 3.7.3 documentation
# https://docs.python.org/3/reference/datamodel.html#object.__new__

# 8.10. Queue — A synchronized queue class — Python 2.7.16 documentation
# https://docs.python.org/2/library/queue.html
# The Queue class in this module implements all the required locking semantics.

# 3. Data model — Python 3.7.3 documentation
# https://docs.python.org/3/reference/datamodel.html#specialnames

# 3. Data model — Python 3.7.3 documentation
# https://docs.python.org/3/reference/datamodel.html#object.__del__

# }
# 注意：
# 线程安全
# 实例析构、类的析构

# 需要测试：
# 1、线程安全
# 2、效率

# TODO 类的析构

import threading


def make_synchronized(func):
    func.__lock__ = threading.Lock()

    def synced_func(*args, **kws):
        with func.__lock__:
            return func(*args, **kws)

    return synced_func


class SdkSingletonBatchHandler(object):
    __instance = None
    # 存放批处理的队列 批处理方法对其按照先进先出FIFO处理
    queueContainer = []
    queueLength = None
    batchHandlerFunc = None
    # 队列生存时间
    timeToLiveSeconds = 0.5
    __bornTime = 0

    @make_synchronized
    def __new__(cls, *args, **kwargs):
        if cls.__instance is None:
            cls.__bornTime = time.time()
            cls.__instance = object.__new__(cls, *args, **kwargs)
        if cls.queueLength is None:
            cls.queueLength = 10
        cls.batchAction()
        return cls.__instance

    @classmethod
    def batchHandler(cls, queueContainer):
        return cls.batchHandlerFunc

    @classmethod
    def batchAction(cls):
        if len(cls.queueContainer) >= cls.queueLength or cls.timeToLiveSeconds < time.time() - cls.__bornTime:
            cls.batchHandler(cls.queueContainer)
            cls.queueContainer = []
            cls.__bornTime = time.time()

    @classmethod
    def diyClassDestruct(cls):
        # Python 2.7.5 自定义类的析构函数，注意不是实例的析构函数
        if len(cls.queueContainer) > 0:
            cls.batchHandler(cls.queueContainer)

    def __del__(self):
        # Python 2.7.5 实例的析构函数
        # 实际测试发现无效
        if len(self.queueContainer) > 0:
            self.batchHandler(self.queueContainer)


import time


def bizFuncNotBatch(param):
    time.sleep(0.02)
    print "do sth" + str(param)


def bizFuncBatch(param):
    def batchHandler(paramList):
        for i in paramList:
            pass
        time.sleep(0.02)
        print "do sth" + str(paramList)

    s = SdkSingletonBatchHandler()
    s.__class__.queueLength = 200
    s.__class__.timeToLiveSeconds = 123
    s.__class__.batchHandlerFunc = batchHandler
    s.__class__.queueContainer.append(param)
    s.__class__.batchAction()
    print "do sth Batch"
    # return 测试所需对象id
    return s


# 测试
# 线程安全

def testThreadSafeWorker():
    s1 = bizFuncBatch("param")
    s2 = bizFuncBatch("param")
    print "id1={},id2={}".format(id(s1), id(s2))


task = []
for i in range(300):
    t = threading.Thread(target=testThreadSafeWorker())
    task.append(t)
for i in task:
    i.start()
for i in task:
    i.join()

# 测试
# 效率

data = [{'i': i, 'v': "value"} for i in range(20)]

consoleInfo = []


def consoleInfoHub(*args):
    global consoleInfo
    s = ("{}" + time.ctime() + "  " + str(time.time())).format(args[0])
    consoleInfo.append(s)


consoleInfoHub("notBatch:Start:")
for i in data:
    bizFuncNotBatch(i)
consoleInfoHub("notBatch:End:")
consoleInfoHub("Batch:Start:")
for i in data:
    bizFuncBatch(i)
consoleInfoHub("Batch:End:")
for i in consoleInfo:
    print i

class TestClassDel(object):
    __instance = None

    def __init__(self):
        print("init")

    def __new__(cls, *args, **kwargs):
        if cls.__instance is None:
            cls.__instance = object.__new__(cls, *args, **kwargs)
        return cls.__instance

    def __del__(self):
        print(1)

s1 = TestClassDel()
s2 = TestClassDel()
del s1
del s2

init
init
1

Python 3.7.3 (v3.7.3:ef4ec6ed12, Mar 25 2019, 22:22:05) [MSC v.1916 64 bit (AMD64)] on win32

class TestClassDel(object):
    __instance = None

    def __init__(self):
        print "init"

    def __new__(cls, *args, **kwargs):
        if cls.__instance is None:
            cls.__instance = object.__new__(cls, *args, **kwargs)
        return cls.__instance

    def __del__(self):
        print 1

s1 = TestClassDel()
s2 = TestClassDel()
del s1
del s2

Python 2.7.5 (default, May 15 2013, 22:44:16) [MSC v.1500 64 bit (AMD64)] on win32

init
init

 没有打印1

 注意以上为单例模式 

class TestClassDel(object):
    __instance = None

    def __init__(self):
        print "init"

    def __new__(cls, *args, **kwargs):
        if cls.__instance is None:
            cls.__instance = object.__new__(cls, *args, **kwargs)
        return cls.__instance

    def __del__(self):
        print 1

s1 = TestClassDel()
s2 = TestClassDel()
del s1
del s2

class T():
    def __call__(self, *args, **kwargs):
        print 1
d=T().__call__()

打印1

受此启发

【注意 目标环境为python2.7.5】